PHOTOACTIVE OPTOELECTRONIC AND TRANSISTOR DEVICES

FIELD

The present invention relates to photoactive optoelectronic devices, such as organic photovoltaic devices, and transistor devices, and to organic compounds for use in the optoelectronic and transistor devices. The present invention also relates to processes for preparing photoactive optoelectronic and transistor devices. BACKGROUND

Photoactive optoelectronic devices include organic photovoltaic devices (OPVs), which are also referred to as organic solar cells, and photosensors where the device signals the detection of particular wavelengths of electromagnetic radiation. Photovoltaic devices include heteroj unction and bilayer organic photovoltaic cells, and hybrid solar cells.

OPVs come with the promise of efficient conversion of sunlight into direct usable electrical energy at a much lower cost than the traditional silicon based solar cells. OPVs contain a combination of electron acceptor materials (n-type

semiconductors) and electron donor materials (p-type semiconductors or hole accepting materials) in the active layer. Absorption of a photon results in the generation of a weakly-bound electron-hole pair (an exciton) in the active layer.

Dissociation of the bound electron-hole pair is facilitated by the interface between the electron donor and electron acceptor materials. The separated holes and electrons travel towards respective electrodes and consequently generate a voltage potential at the electrodes.

One of the most studied areas of OPVs are heteroj unction devices that involve the use of poly 3-hexylthiophene (P3HT) as an example of a polymeric organic material used as the electron donor material, together with a fullerene derivative as the electron acceptor material. The two materials may be present as layers, forming a bilayer photovoltaic cell, or may be present as a blend, forming a bulk heterojunction photovoltaic cell. In bulk heterojunction photovoltaic cells the donor material (or p-type conductor) and acceptor material (n-type conductor) are presented in a blend in the active (specifically, photoactive) layer of a device, and the concentration of each component often gradually increases when approaching the corresponding electrode. This provides an increase in the total surface area of the junctions between the materials and facilitates dissociation of the exciton.

Much of the research on heterojunction OPV devices since the 1990's has focused upon the discovery of many new electron donor materials that can be used in place of P3HT. In contrast there has been much more limited and less successful discovery of new electron accepting materials that can be used in place of fullerene derivatives (Angewandte Chemie International Edition, 2012, 51 , 2020-2068.)

Fullerenes have been optimised for use in solar cells providing power conversion efficiencies in the range 3 to 10% when combined with selected commercial and experimental electron donor materials. Fullerenes tend to be poor at harvesting visible sunlight, and are difficult to synthesize and purify. In principle small molecule electron acceptor compounds are cheap, easy to synthesize and purify, but it has proven difficult to discover compounds of this type that can be used to fabricate OPV devices with efficient power conversion efficiencies.

Organic transistors are promising candidates for application in integrated circuits, sensors and displays. Practical exploitation of organic electronic circuitry requires the use of both p-channel transistors, which are fabricated from electron donor materials, and n-channel transistors, which are fabricated from electron acceptor materials, to produce complementary circuits, which show greater speed, reliability and stability than those of unipolar circuits. Whereas much progress has been made in the discovery of electron donor semiconductors for use in transistors, the development of high-performance, ambient-stable electron acceptor semiconductors has lagged far behind, particularly as far as solution-processable electron acceptor semiconductors are concerned (Advanced Materials, 2010, 22, 1331-1345).

Accordingly, there is a need for identifying organic compounds, in particular electron acceptor or n-type semiconductor compounds, that can be used in photoactive optoelectronic devices, such as OPV heterojunction devices, or transistor devices.

SUMMARY

In a first aspect, there is provided a photoactive optoelectronic device comprising:

a first electrode;

a second electrode; and

at least one organic light-absorbing electroactive layer in electrical connection with the first and second electrodes, that generates an electrical current in response to electromagnetic radiation, wherein the light-absorbing electroactive layer comprises an electron donor material and an electron acceptor material, the electron acceptor material comprising a com stereoisomers thereof:

Terminal

Group

Formula 1

wherein

D is a conjugated group that provides at least one conjugated pathway between at least two terminal groups and which is selected from one or more optionally substituted, optionally fused, rings provided that at least one of the rings is aromatic; n is an integer of 2 to 20;

A is independently selected for each terminal group from an optionally substituted 5, 6 or 7 membered carbocyclic or heterocyclic ring, which is optionally fused with one or more aryl or heteroaryl rings;

X ¹ is independently selected for each terminal group from O, S and CR ¹ R ² , wherein R ¹ and R ² are each independently selected from CN and C0 ₂ R ³ , R ³ is selected from optionally substituted d-Ci ₀ alkyl, optionally substituted C ₂ -Ci ₀ alkenyl, optionally substituted C ₂ -Ci ₀ alkynyl, optionally substituted aryl and arylCi-Ci ₀ alkyl.

The photoactive optoelectronic device generates an electrical current in response to electromagnetic radiation. An example of this class of device is an organic photovoltaic device (OPV), which is also referred to as an organic solar cell. This type of device may be a heterojunction OPV, bilayer OPV or hybrid solar cell (OSC).

Another type of device is a photosensor where the device signals the detection of particular wavelengths of electromagnetic radiation. In one embodiment, the organic OPV device is a bulk heterojunction OPV device.

In a second aspect, there is provided a transistor device comprising:

a gate electrode;

a gate insulating layer;

source and drain electrodes; and

a channel-forming region;

the gate electrode, the gate insulating layer, the source and drain electrodes, and the channel-forming region being disposed on a base, and wherein the channel- forming region comprises an electron acceptor material comprising a compound according to Formula 1 or stereoisomers thereof:

Terminal

Group

Formula 1

wherein

D is a conjugated group that provides at least one conjugated pathway between at least two terminal groups and which is selected from one or more optionally substituted, optionally fused, rings provided that at least one of the rings is aromatic; n is an integer of 2 to 20;

A is independently selected for each terminal group from an optionally substituted 5, 6 or 7 membered carbocyclic or heterocyclic ring, which is optionally fused with one or more aryl or heteroaryl rings;

X ¹ is independently selected for each terminal group from O, S and CR ¹ R ² , wherein R ¹ and R ² are each independently selected from CN and C0 ₂ R ³ , R ³ is selected from optionally substituted d-Ci ₀ alkyl, optionally substituted C ₂ -Ci ₀ alkenyl, optionally substituted C ₂ -Ci ₀ alkynyl, optionally substituted aryl and arylCi-Ci ₀ alkyl.

The compounds of Formula 1 comprise at least two terminal groups separated by the conjugated group D. The integer n may be any integer of 2 to 10. In one embodiment, n is an integer of 2 or 4. For example, when n is 2, a compound of Formula 1 is provided as follows:

Terminal Terminal

Group Group

wherein A, X and D, are as described in the first or second aspect above, or embodiments described herein.

When n is 4 a compound of Formula 1 may be provided as follows:

wherein A, X and D, are as described in the first or second aspect above, or embodiments described herein.

In a third aspect, there is provided an electron acceptor material comprising a compound according to Formula 1 described above or a stereoisomer thereof.

The electron acceptor material can be used as an n-type semiconductor material. An electron donor material, which can be used as a p-type semiconductor, can be associated with the electron acceptor material to provide an active material for a photoactive optoelectronic device. In one embodiment, there is provided an active material for use in a photoactive optoelectronic device, wherein the active material comprises an electron donor material and an electron acceptor material comprising a compound according to Formula 1 as described herein. The active material is photoactive, and may for example be suitable for use in an OPV device. The association of the electron donor and electron acceptor material may be layered or mixed, for example provided as a bilayer or bulk heterojunction.

In one embodiment, the electron donor material is P3HT.

In a fourth aspect, there is provided a compound of Formula 2 or stereoisomers thereof:

Terminal

Group

Formula 2

wherein

n is an integer of 2 to 20; X ¹ is independently selected for each terminal group from O, S and CR ¹ R ² ; L is selected from N, NR ⁴ , O, S, Se, S0 ₂ , CR ⁴ , CR ⁴ R ⁵ and C=X ² ; wherein X ² is selected from O, S and CR ¹ R ² ;

m is an integer selected from 0, 1 and 2;

G is independently selected from N, NR ⁴ , O, S, Se, S0 ₂ , CR ⁴ , CR ⁴ R ⁵ and C=X ³ ; wherein X ³ is selected from O, S and CR ¹ R ² , and optionally when m is 2 then two G groups are joined together to form an optionally substituted aryl or heteroaryl ring fused to the A ring;

E ¹ and E ² are each independently selected from C=0, C=S, N, NR ⁴ , O, S, S0 ₂ , CR ⁴ and CR ⁴ R ⁵ ; and when m is 0 are optionally joined together to form one or more optionally substituted aryl or heteroaryl ring fused to the A ring, and when m is 1 or 2 each of E ¹ and E ² are optionally independently joined with G to form one or more optionally substituted aryl or heteroaryl ring fused to the A ring;

R ¹ and R ² are each independently selected from CN and C0 ₂ R ³ , R ³ is selected from optionally substituted d-Ci ₀ alkyl, optionally substituted C ₂ -Ci ₀ alkenyl, optionally substituted C ₂ -Ci ₀ alkynyl, optionally substituted aryl and arylCi-Ci ₀ alkyl; and

R ⁴ and R ⁵ are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted CrC ₂₀ haloalkyl, optionally substituted C C ₂₀ alkylamino, optionally substituted C ₃ -C ₂₀ cycloalkyl, optionally substituted C ₂ - C ₂₀ alkenyl, optionally substituted C ₃ -C ₂₀ cycloalkenyl, optionally substituted C ₂ - C ₂₀ alkynyl, optionally substituted C ₃ -C ₂₀ cycloalkynyl, optionally substituted aryl and arylCrC ₂₀ alkyl.

D is a conjugated group that provides at least one conjugated pathway between at least two terminal groups and which is selected from one or more optionally substituted, optionally fused, rings provided that at least one of the rings is aromatic, and which is selected from a grou ula 3

Formula 3

wherein

p is independently selected from an integer of 0 to 15;

Z ¹ is independently selected from O, S, Se, S0 ₂ , NR ¹² , CR ¹² R ¹³ and

SiR ¹² R Z ² and Z ³ are each independently selected from N and CR ¹² ;

Ar is selected from an optionally substituted, optionally fused, aryl or heteroaryl group;

with the provisos:

when n is 2, m is 1 , X ¹ is O, L is C=0, and G is C=X ² , E ¹ and E ² are NH, NCH ₃ or N(C ₂ H ₅ ), p is 0, and Ar is selected from optionally substituted, optionally fused, thiophene groups, then at least two thiophene groups are fused together;

when n is 2, m is 1 , X ¹ is O, L is C=0, and G is C=X ² , E ¹ and E ² are NH, NCH ₃ or N(C ₂ H ₅ ), p is at least 1 , each Z ¹ is S, each Z ² and Z ³ are CH, and Ar is selected from optionally substituted, optionally fused, thiophene groups, then at least two thiophene groups are fused together;

when n is 2, m is 0 and G is absent, E ¹ and E ² are C=S, N(C ₂ H ₅ ) or joined together to form a benzene ring fused to the A ring, L is S, S0 ₂ or C=X ² , X ¹ and X ² are O or C(CN) ₂ , p is 0, and Ar is selected from optionally substituted, optionally fused, thiophene groups, then at least two thiophene groups are fused together;

when n is 2, m is 0 and G is absent, E ¹ and E ² are C=S, N(C ₂ H ₅ ) or joined together to form a benzene ring fused to the A ring, L is S, S0 ₂ or C=X ² , X ¹ and X ² are O or C(CN) ₂ , p is at least 1 , each Z ¹ is S, each Z ² and Z ³ are CH, and Ar is selected from optionally substituted, optionally fused, thiophene groups, then at least two thiophene groups are fused together;

when n is 2, m is 0 and G is absent, E ¹ and E ² are joined together to form a benzene ring fused to the A ring, L is S0 ₂ or C=X ² , X ¹ and X ² are O or C(CN) ₂ , and Ar is selected from one or more benzene groups, then p is at least 1.

The integer n may be any integer of 2 to 20, such as an integer of 2 to 10. For example, in one embodiment when n is 2, a compound of Formula 2 is provided as follows:

Terminal Group Conjugated Group Terminal Group

wherein for the conjugated group, p ¹ and p ² are each independently selected from an integer of 0 to 15, and Ar, Z ¹ , Z ² and Z ³ , are each independently selected from the groups as described in the fourth aspect above, or embodiments described herein; and for each terminal group A, X ¹ , L, E ¹ , E ² , G and m, are each independently selected from the groups as described in the fourth aspect above, or embodiments described herein.

In another embodiment, when n is 4, a compound of Formula 2 is provided as follows:

wherein for the conjugated group, p ¹ , p ² , p ³ and p ⁴ , are each independently selected from an integer of 0 to 15, and Ar, Z ¹ , Z ² and Z ³ , are each independently selected from the groups as described in the fourth aspect above, or embodiments described herein; and for each terminal group A, X ¹ , L, E ¹ , E ² , G and m, are each independently selected from the groups as described in the fourth aspect above, or embodiments described herein.

The following embodiments are described for the above aspects.

In Formula 1 and Formula 2, n is an integer of 2 to 20, and therefore the compounds of Formula 1 comprise at least two terminal groups A. In one embodiment, n is an integer of 2 to 10. In another embodiment, n is an integer of 2 to 4. In a further embodiment, n is 2 or 4.

For the terminal group, in one embodiment X is O. For the terminal group, A may be an optionally substituted, optionally fused, 5, 6 or 7 membered heterocyclic ring, wherein the heteroatoms of the heterocyclic ring may be selected from O, N and S. In another embodiment, A may be an optionally substituted, optionally fused, 5, 6 or 7 membered carbocyclic ring.

The A ring may be optionally fused, such as fused with a monocyclic aromatic group, for example benzene, or fused with a polycyclic aromatic group containing 2 to 4 aryl rings, for example naphthalene and anthracene, or fused with an aromatic heterocyclic ring system containing 1 to 4 rings, for example quinazoline and acridine. The fused ring systems may each be optionally substituted. The conjugated group D provides a conjugated π bond system that has at least one conjugated pathway between at least two terminal groups A. The conjugated group D may be one or more optionally substituted, optionally fused, rings joined or fused together to provide the conjugated π bond system. The D group may be selected from one or more optionally substituted, optionally fused, aryl and heteroaryl groups that are joined or fused together to provide the conjugated pathway.

The D group may have from 5 to 100 ring atoms, from 5 to 60 ring atoms, from 5 to 50 ring atoms, from 5 to 30 ring atoms, or from 5 to 20 ring atoms. The D group may consist of at least 2 aromatic rings, at least 4 aromatic rings, or at least 6 aromatic rings. The D group may consist of 20 aromatic rings or less, 15 aromatic rings or less, or 10 aromatic rings or less. For example, the D group may consist of any number or range of aromatic rings selected from the following: 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15.

The optionally substituted, optionally fused, aryl and heteroaryl groups may be formed from one or more 5, 6 or 7 membered rings. The D group may include optionally substituted, optionally fused, carbocyclic or heterocyclic groups. In one embodiment, the D group is one or more optionally substituted, optionally fused, aryl groups. The optionally substituted aryl groups may be monocyclic or polycyclic. The optionally substituted monocyclic aryl groups may be a 6 membered ring, such as optionally substituted benzene. The optionally substituted polycyclic aryl groups may be two or more 6-member rings fused together, such as naphthalene, anthracene, pyrene, tetracene, and pentacene, which may each be optionally substituted. The optionally substituted polycyclic aryl groups may be two or more 6 member rings joined together, such as biphenyl, or two or more fused rings that are joined together, such as fluorene and perylene, and which may each be optionally substituted. In one embodiment, the D group is selected from one or more optionally substituted, optionally fused, heteroaryl groups. The optionally substituted heteroaryl groups may be monocyclic or polycyclic. The optionally substituted heteroaryl groups may be selected from 5-membered monocyclic rings, such as thiophene, furan, pyrrole, silole, imidazole, 1 ,3-thiazole, 1 ,3,4-oxadiazole, 1 ,3,4-thiadiazole, or 6 membered rings, such as pyridine and triazine, which may each be optionally substituted. The heteroaryl groups may be polycyclic rings, which may contain fused or joined aryl groups, such as benzothiadiazole and carbazole, and which may be each optionally substituted. The D group may consist of optionally substituted aryl and heteroaryl groups as described above that may be joined or fused together to provide a conjugated π bond system. ln one particular embodiment, the D group has 5 to 100 ring atoms formed from one or more groups selected from benzene, naphthalene, thiophene, furan, biphenyl and fluorene, that are joined or fused together to provide the conjugated π bond system, and wherein each group may each be optionally substituted.

5 The D group, or any groups thereof, may be substituted as herein described with one or more optional substituents. The optional substituents of the D group may be selected from halogen, cyano, CrC ₂₀ alkyl, CrC ₂₀ haloalkyl, d-C^oalkylamino, C ₃ - C ₂ ocycloalkyl, C ₂ -C ₂₀ alkenyl, C ₃ -C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkynyl, C C ₂₀ alkylsilyl, C ₂ -C ₂₀ alkenylsilyl, C ₂ -C ₂₀ alkynylsilyl, aryl, arylC _r 2oalkyl, heteroaryl and i o heteroaryld-2oalkyl. and wherein alkyl, haloalkyl, alkylamino, cycloalkyl, alkenyl,

cycloalkenyl, alkynyl, cycloalkynyl, alkylsilyl, alkenylsilyl, alkynylsilyl, aryl, heteroaryl, arylalkyl and heteroarylalkyl, in each occurrence may be optionally substituted. In one embodiment, the substituents are selected from C ₄ _i ₂ alkyl and C ₄ _i ₂ cycloalkyl.

In a fifth aspect, there is provided a process for preparing a thin film component 15 for a photoactive optoelectronic device comprising the steps of:

providing a solution comprising a solvent and an electron acceptor material selected from one or more compounds as described in the above aspects and embodiments thereof,

optionally adding an electron donor material and/or an additive to the solution; 20 depositing the solution onto an optionally coated anode or cathode material; and

optionally evaporating the solvent from the deposited solution.

In one embodiment, the depositing of the solution is by spin coating. In a sixth aspect, there is provided a process for preparing a thin film 25 component comprising an electron acceptor material selected from one or more of the compounds as described in the above aspects and embodiments thereof for a photoactive optoelectronic device, the process comprising the step of vapour deposition of one or more of the compounds onto a substrate.

In a seventh aspect, there is provided a process for preparing a thin film 30 component for a transistor device comprising the steps of:

providing a solution comprising a solvent and one or more compounds as described in the above aspects and embodiments thereof;

optionally adding an additive to the solution;

depositing the solution onto a transistor substrate; and

35 optionally evaporating the solvent from the deposited solution. In one embodiment, the depositing of the solution is by spin coating.

The organic solvent for the above aspects may be selected from chloroform, tetrachloroethane, tetrahydrofuran, toluene, tetrahydronaphthalene, anisole, xylene, mesitylene, ethyl acetate, methyl ethyl ketone, dimethyl formamide, chlorobenzene, dichlorobenzene, trichlorobenzene and propylene glycol monomethyl ether acetate (PGMEA).

In an eighth aspect, there is provided a process for preparing a thin film component comprising an electron acceptor material selected from one or more of the compounds as described in the above aspects and embodiments thereof for a transistor device, the process comprising the step of vapour deposition of one or more of the compounds onto a transistor substrate.

In a ninth aspect, there is provided a process for preparing the compounds as described herein according to any one of the synthetic schemes described herein. In one embodiment, there is provided a process for preparing a compound according to Formula 1 as described herein, the process comprising the step of reacting n terminal groups of:

Terminal Group

with a conjugated group D to form a compound according of Formula 1.

In another embodiment, there is provided a process for preparing a compound according to Formula 1 as described herein, the process comprising the step of reacting n terminal groups of:

Terminal Group

with a conjugated group D selected from at least one of (Ar)-Ln and

wherein X ¹ , A, Ar, n, p, Z ¹ , Z ² and Z ³ are as defined herein, and L is a group selected from halo, aldehyde and dioxaborinane, to form a compound according of Formula 1.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be further described and illustrated, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a general configuration of a bilayer organic solar cell device according to one embodiment of the invention;

Figure 2 shows a general configuration of a bulk heteroj unction organic solar cell device according to one embodiment of the invention;

Figures 3, 4 & 5 show l-V curves from testing of solar cell devices according to embodiments on the invention;

Figure 6 shows bottom gate/top contact transistor architecture with a surface treatment applied to the dielectric layer, according to one embodiment of the invention; and

Figures 7 and 8 show the output and transfer curves respectively for transistor device Example 1.

DETAILED DESCRIPTION

The present invention is described in the following various non-limiting embodiments, which relate to investigations undertaken to identify organic compounds for advantageous use as semiconductor materials in photoactive optoelectronic devices. It was surprisingly found that a range of organic compounds are useful as semiconductors materials in photoactive optoelectronic and transistor devices, and in particular as n-type semiconductors, which may be provided by the electron acceptor materials as described herein. TERMS

The term "conjugated" as used herein refers to a molecule having two or more double and/or triple bonds in sequence, each double or triple bond being separated from the next consecutive double or triple bond by a single bond so that π orbitals overlap not only across the double or triple bond, but also across adjacent single bonds located between adjacent double and/or triple bonds.

As will be understood, an aromatic group means a cyclic group having 4 m+2 π electrons, where m is an integer equal to or greater than 1. As used herein, "aromatic" is used interchangeably with "aryl" to refer to an aromatic group, regardless of the valency of aromatic group. Thus, aryl refers to monovalent aromatic groups, bivalent aromatic groups and higher multivalency aromatic groups.

The term "joined" refers to a ring, moiety or group that is joined to at least one other ring, moiety or group by a single covalent bond.

The term "fused" refers to one or more rings that share at least two common ring atoms with one or more other rings.

A heteroaromatic group is an aromatic group or ring containing one or more heteroatoms, such as N, O, S, Se, Si or P. As used herein, "heteroaromatic" is used interchangeably with "heteroaryl", and a heteroaryl group refers to monovalent aromatic groups, bivalent aromatic groups and higher multivalency aromatic groups containing one or more heteroatoms.

The term "optionally substituted" means that a functional group is either substituted or unsubstituted, at any available position. Substitution can be with one or more functional groups selected from, e.g., alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, heterocyclyl, heteroaryl, formyl, alkanoyl, cycloalkanoyl, aroyl, heteroaroyl, carboxyl, alkoxycarbonyl, cycloalkyloxycarbonyl, aryloxycarbonyl, heterocyclyloxycarbonyl, heteroaryloxycarbonyl, alkylaminocarbonyl,

cycloalkylaminocarbonyl, arylaminocarbonyl, heterocyclylaminocarbonyl,

heteroarylaminocarbonyl, cyano, alkoxy, cycloalkoxy, aryloxy, heterocyclyloxy, heteroaryloxy, alkanoate, cycloalkanoate, aryloate, heterocyclyloate, heteroaryloate, alkylcarbonylamino, cycloalkylcarbonylamino, arylcarbonylamino,

heterocyclylcarbonylamino, heteroarylcarbonylamino, nitro, alkylthio, cycloalkylthio, arylthio, heterocyclylthio, heteroarylthio, alkylsulfonyl, cycloalkylsulfonyl, arylsulfonyl, heterocyclysulfonyl, heteroarylsulfonyl, hydroxyl, halo, haloalkyl, haloaryl,

haloheterocyclyl, haloheteroaryl, haloalkoxy, haloalkylsulfonyl, silylalkyl, alkenylsilylalkyl, and alkynylsilylalkyl. It will be appreciated that other groups not specifically described may also be used.

"Alkyl" whether used alone, or in compound words such as alkoxy, alkylthio, alkylamino, dialkylamino or haloalkyl, represents straight or branched chain

hydrocarbons ranging in size from one to about 20 carbon atoms, or more. Thus alkyl moieties include, unless explicitly limited to smaller groups, moieties ranging in size, for example, from one to about 6 carbon atoms or greater, such as, methyl, ethyl, n- propyl, iso-propyl and/or butyl, pentyl, hexyl, and higher isomers, including, e.g., those straight or branched chain hydrocarbons ranging in size from about 6 to about 20 carbon atoms, or greater.

"Alkenyl" whether used alone, or in compound words such as alkenyloxy or haloalkenyl, represents straight or branched chain hydrocarbons containing at least one carbon-carbon double bond, including, unless explicitly limited to smaller groups, moieties ranging in size from two to about 6 carbon atoms or greater, such as, methylene, ethylene, 1-propenyl, 2-propenyl, and/or butenyl, pentenyl, hexenyl, and higher isomers, including, e.g., those straight or branched chain hydrocarbons ranging in size, for example, from about 6 to about 20 carbon atoms, or greater.

"Alkynyl" whether used alone, or in compound words such as alkynyloxy, represents straight or branched chain hydrocarbons containing at least one carbon- carbon triple bond, including, unless explicitly limited to smaller groups, moieties ranging in size from, e.g., two to about 6 carbon atoms or greater, such as, ethynyl, 1- propynyl, 2-propynyl, and/or butynyl, pentynyl, hexynyl, and higher isomers, including, e.g., those straight or branched chain hydrocarbons ranging in size from, e.g., about 6 to about 20 carbon atoms, or greater.

"Cycloalkyl" represents a mono- or polycarbocyclic ring system of varying sizes, e.g., from about 3 to about 20 carbon atoms, e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl. The term cycloalkyloxy represents the same groups linked through an oxygen atom such as cyclopentyloxy and cyclohexyloxy. The term cycloalkylthio represents the same groups linked through a sulfur atom such as cyclopentylthio and cyclohexylthio.

"Cycloalkenyl" represents a non-aromatic mono- or polycarbocyclic ring system, e.g., of about 3 to about 20 carbon atoms containing at least one carbon-carbon double bond, e.g., cyclopentenyl, cyclohexenyl or cycloheptenyl. The term "cycloalkenyloxy" represents the same groups linked through an oxygen atom such as cyclopentenyloxy and cyclohexenyloxy. The term "cycloalkenylthio" represents the same groups linked through a sulfur atom such as cyclopentenylthio and cyclohexenylthio.

The terms, "carbocyclic" and "carbocyclyl" represent a ring system wherein the ring atoms are all carbon atoms, e.g., of about 3 to about 20 carbon atoms, and which may be aromatic, non-aromatic, saturated, or unsaturated, and may be substituted and/or carry fused rings. Examples of such groups include benzene, cyclopentyl, cyclohexyl, or fully or partially hydrogenated phenyl, naphthyl and fluorenyl.

"Aryl" whether used alone, or in compound words such as arylalkyl, aryloxy or arylthio, represents: (i) an optionally substituted mono- or polycyclic aromatic carbocyclic moiety, e.g., of about 6 to about 100 carbon atoms, such as phenyl, naphthyl or fluorenyl; or, (ii) an optionally substituted partially saturated polycyclic carbocyclic aromatic ring system in which an aryl and a cycloalkyl or cycloalkenyl group are fused together to form a cyclic structure such as a tetrahydronaphthyl, indenyl jndanyl or fluorene ring.

"Heterocyclyl" or "heterocyclic" whether used alone, or in compound words such as heterocyclyloxy represents: (i) an optionally substituted cycloalkyl or cycloalkenyl group, e.g., of about 3 to about 100 ring members, which may contain one or more heteroatoms such as nitrogen, oxygen, or sulfur (examples include pyrrolidinyl, morpholino, thiomorpholino, or fully or partially hydrogenated thienyl, furyl, pyrrolyl, thiazolyl, oxazolyl, oxazinyl, thiazinyl, pyridyl and azepinyl); (ii) an optionally substituted partially saturated polycyclic ring system in which an aryl (or heteroaryl) ring and a heterocyclic group are fused together to form a cyclic structure (examples include chromanyl, dihydrobenzofuryl and indolinyl); or (iii) an optionally substituted fully or partially saturated polycyclic fused ring system that has one or more bridges (examples include quinuclidinyl and dihydro-1 ,4-epoxynaphthyl).

"Heteroaryl" or "hetaryl" whether used alone, or in compound words such as heteroaryloxy represents: (i) an optionally substituted mono- or polycyclic aromatic organic moiety, e.g., of about 5 to about 20 ring members in which one or more of the ring members is/are element(s) other than carbon, for example nitrogen, oxygen, sulfur or silicon; the heteroatom(s) interrupting a carbocyclic ring structure and having a sufficient number of delocalized pi electrons to provide aromatic character, provided that the rings do not contain adjacent oxygen and/or sulfur atoms. Typical 6-membered heteroaryl groups are pyrazinyl, pyridazinyl, pyrazolyl, pyridyl and pyrimidinyl. All regioisomers are contemplated, e.g., 2-pyridyl, 3-pyridyl and 4-pyridyl. Typical 5- membered heteroaryl rings are furyl, imidazolyl, oxazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, pyrrolyl, 1 ,3,4-thiadiazolyl, thiazolyl, thienyl, triazolyl, and silole. All regioisomers are contemplated, e.g., 2-thienyl and 3-thienyl. Bicyclic groups typically are benzo-fused ring systems derived from the heteroaryl groups named above, e.g., benzofuryl, benzimidazolyl, benzthiazolyl, indolyl, indolizinyl, isoquinolyl, quinazolinyl, quinolyl and benzothienyl; or, (ii) an optionally substituted partially saturated polycyclic heteroaryl ring system in which a heteroaryl and a cycloalkyi or cycloalkenyl group are fused together to form a cyclic structure such as a tetrahydroquinolyl or pyrindinyl ring.

"Formyl" represents a -CHO moiety.

"Alkanoyl" represents a -C(=0)-alkyl group in which the alkyl group is as defined supra. In a particular embodiment, an alkanoyl ranges in size from about C ₂ - C ₂₀ . One example is acyl.

"Aroyl" represents a -C(=0)-aryl group in which the aryl group is as defined supra. In a particular embodiment, an aroyl ranges in size from about C ₇ -C ₂₀ .

Examples include benzoyl and 1-naphthoyl and 2-naphthoyl.

"Heterocycloyl" represents a -C(=0)-heterocyclyl group in which the heterocylic group is as defined supra. In a particular embodiment, an heterocycloyl ranges in size from about C ₄ -C ₂₀ .

"Heteroaroyl" represents a -C(=0)-heteroaryl group in which the heteroaryl group is as defined supra. In a particular embodiment, a heteroaroyl ranges in size from about C6"C ₂ o. An example is pyridylcarbonyl.

"Carboxyl" represents a -C0 ₂ H moiety.

"Oxycarbonyl" represents a carboxylic acid ester group -C0 ₂ R which is linked to the rest of the molecule through a carbon atom.

"Alkoxycarbonyl" represents an -C0 ₂ -alkyl group in which the alkyl group is as defined supra. In a particular embodiment, an alkoxycarbonyl ranges in size from about C ₂ -C ₂₀ . Examples include methoxycarbonyl and ethoxycarbonyl.

"Aryloxycarbonyl" represents an -C0 ₂ -aryl group in which the aryl group is as defined supra. Examples include phenoxycarbonyl and naphthoxycarbonyl.

"Heterocyclyloxycarbonyl" represents a -C0 ₂ -heterocyclyl group in which the heterocyclic group is as defined supra.

"Heteroaryloxycarbonyl" represents a -CO-heteroaryl group in which the heteroaryl group is as defined supra.

"Aminocarbonyl" represents a carboxylic acid amide group -C(=0)NHR or - C(=0)NR ₂ which is linked to the rest of the molecule through a carbon atom. "Alkylaminocarbonyl" represents a -C(=0)NHR or -C(=0)NR ₂ group in which R is an alkyl group as defined supra.

"Arylaminocarbonyl" represents a -C(=0)NHR or -C(=0)NR ₂ group in which R is an aryl group as defined supra.

"Heterocyclylaminocarbonyl" represents a -C(=0)NHR or -C(=0)NR ₂ group in which R is a heterocyclic group as defined supra. In certain embodiments, NR ₂ is a heterocyclic ring, which is optionally substituted.

"Heteroarylaminocarbonyl" represents a -C(=0)NHR or -C(=0)NR ₂ group in which R is a heteroaryl group as defined supra. In certain embodiments, NR ₂ is a heteroaryl ring, which is optionally substituted.

"Cyano" represents a -CN moiety.

"Hydroxyl" represents a -OH moiety.

"Alkoxy" represents an -O-alkyl group in which the alkyl group is as defined supra. Examples include methoxy, ethoxy, n-propoxy, iso-propoxy, and the different butoxy, pentoxy, hexyloxy and higher isomers.

"Aryloxy" represents an -O-aryl group in which the aryl group is as defined supra. Examples include, without limitation, phenoxy and naphthoxy.

"Alkenyloxy" represents an -O-alkenyl group in which the alkenyl group is as defined supra. An example is allyloxy.

"Heterocyclyloxy" represents an -O-heterocyclyl group in which the heterocyclic group is as defined supra.

"Heteroaryloxy" represents an -O-heteroaryl group in which the heteroaryl group is as defined supra. An example is pyridyloxy.

"Alkanoate" represents an -OC(=0)-R group in which R is an alkyl group as defined supra.

"Aryloate" represents a -OC(=0)-R group in which R is an aryl group as defined supra.

"Heterocyclyloate" represents an -OC(=0)~R group in which R is a heterocyclic group as defined supra.

"Heteroaryloate" represents an -OC(=0)-R group in which P is a heteroaryl group as defined supra.

"Amino" represents an -NH ₂ moiety.

"Alkylamino" represents an -NHR or -NR ₂ group in which R is an alkyl group as defined supra. Examples include, without limitation, methylamino, ethylamino, n- propylamino, isopropylamino, and the different butylamino, pentylamino, hexylamino and higher isomers.

"Arylamino" represents an -NHR or -NR ₂ group in which R is an aryl group as defined supra. An example is phenylamino.

"Heterocyclylamino" represents an -NHR or -NR ₂ group in which R is a heterocyclic group as defined supra. In certain embodiments, NR ₂ is a heterocyclic ring, which is optionally substituted.

"Heteroarylamino" represents a -NHR or ~NR ₂ group in which R is a heteroaryl group as defined supra. In certain embodiments, NR ₂ is a heteroaryl ring, which is optionally substituted.

"Carbonylamino" represents a carboxylic acid amide group -NHC(=0)R that is linked to the rest of the molecule through a nitrogen atom.

"Alkylcarbonylamino" represents a -NHC(=0)R group in which R is an alkyl group as defined supra.

"Arylcarbonylamino" represents an -NHC(=0)R group in which R is an aryl group as defined supra.

"Heterocyclylcarbonylamino" represents an -NHC(=0)R group in which R is a heterocyclic group as defined supra.

"Heteroarylcarbonylamino" represents an -NHC(=0)R group in which R is a heteroaryl group as defined supra.

"Nitro" represents a -N0 ₂ moiety.

"Alkylthio" represents an -S-alkyl group in which the alkyl group is as defined supra. Examples include, without limitation, methylthio, ethylthio, n-propylthio, iso propylthio, and the different butylthio, pentylthio, hexylthio and higher isomers.

"Arylthio" represents an -S-aryl group in which the aryl group is as defined supra. Examples include phenylthio and naphthylthio.

"Heterocyclylthio" represents an -S-heterocyclyl group in which the heterocyclic group is as defined supra.

"Heteroarylthio" represents an -S-heteroaryl group in which the heteroaryl group is as defined supra.

"Sulfonyl" represents an -S0 ₂ R group that is linked to the rest of the molecule through a sulfur atom.

"Alkylsulfonyl" represents an -S0 ₂ -alkyl group in which the alkyl group is as defined supra. "Arylsulfonyl" represents an -S0 ₂ -aryl group in which the aryl group is as defined supra.

"Heterocyclylsulfonyl" represents an -S0 ₂ -heterocyclyl group in which the heterocyclic group is as defined supra.

"Heteoarylsulfonyl" presents an -S0 ₂ -heteroaryl group in which the heteroaryl group is as defined supra.

"Aldehyde" represents a -C(=0)H group.

"Alkanal" represents an alkyl-(C=0)H group in which the alkyl group is as defined supra.

"Alkylsilyl" presents an alkyl group that is linked to the rest of the molecule through the silicon atom, which may be substituted with up to three independently selected alkyl groups in which each alkyl group is as defined supra.

"Alkenylsilyl" presents an alkenyl group that is linked to the rest of the molecule through the silicon atom, which may be substituted with up to three independently selected alkenyl groups in which each alkenyl group is as defined supra.

"Alkynylsilyl" presents an alkynyl group that is linked to the rest of the molecule through the silicon atom, which may be substituted with up to three independently selected alkynyl groups in which each alkenyl group is as defined supra.

The term "halo" or "halogen" whether employed alone or in compound words such as haloalkyl, haloalkoxy or haloalkylsulfonyl, represents fluorine, chlorine, bromine or iodine. Further, when used in compound words such as haloalkyl, haloalkoxy or haloalkylsulfonyl, the alkyl may be partially halogenated or fully substituted with halogen atoms which may be independently the same or different. Examples of haloalkyl include, without limitation, -CH ₂ CH ₂ F, -CF ₂ CF ₃ and -CH ₂ CHFCI. Examples of haloalkoxy include, without limitation, -OCHF ₂ , -OCF ₃ , -OCH ₂ CCI ₃ , -

OCH ₂ CF ₃ and -OCH ₂ CH ₂ CF ₃ . Examples of haloalkylsulfonyl include, without limitation, -S0 ₂ CF ₃ , -S0 ₂ CCI ₃ , -S0 ₂ CH ₂ CF ₃ and -S0 ₂ CF ₂ CF ₃ .

ORGANIC ELECTRONIC DEVICES

Photoactive optoelectronic devices

The compounds of the invention described herein can be suitably used in photoactive optoelectronic devices. Photoactive optoelectronic devices, such as a photovoltaic device, generally comprise an active material in electrical connection with a first and second electrode, wherein the active material comprises an electron donor material and an electron acceptor material. The electron acceptor material can be provided by a compound according to Formula 1 or Formula 2 as defined herein. The invention is generally described below with reference to a photovoltaic device, although it will be appreciated that other types of photoactive optoelectronic devices may apply.

A photovoltaic device generates an electrical current upon the absorption of photons. In other words, the active material is arranged such that the device generates an electrical current upon the absorption of the photons.

The compounds of Formula 1 or Formula 2 can act as an electron acceptor material in the device, for example as an n-type semiconductor. The electron donor material can donate an electron to the electron acceptor material in the device upon the absorption of photons, for example act as a p-type semiconductor. The electron donor material may be selected from any electron donor materials known in the art. The electron donor materials are generally organic electron donors, such as conductive polymers including polythiophenes (including P3HT) and the like.

The device may be in the form of an organic solar cell, such as a bulk heteroj unction organic solar cell or a bilayer organic solar cell.

In the case of bilayer organic solar cells, the electron acceptor material and electron donor material can be provided in the device as discrete layers.

In the case of a bulk heterojunction photovoltaic cells, the electron donor material (p-type conductor) and electron acceptor material (n-type conductor) can be provided as a mixed blend in an active material layer of the device. According to one embodiment, the concentration of each of the electron acceptor material and electron donor material in the active material gradually increases when approaching its respective electrode.

The first electrode may be an anode. Any suitable anode materials can be used. The anode material is suitably a transparent anode material. According to some embodiments the anode is a metal oxide anode, including doped metal oxides, such as fluorine tin oxide (FTO), indium tin oxide (ITO), conductive polymer layers or graphene or single-walled carbon nanotubes (SWCNT) or grids or meshes of metals such as gold or silver, and the like. The anode may be supported on a suitable support.

Supports include transparent supports, such as glass or polymer plates.

The second electrode may be a cathode. Any suitable cathode material can be used. According to some embodiments the cathode is a metal or metal alloy, or graphene or single-walled carbon nanotubes (SWCNT). Suitable metals and alloys are well known in the art and include aluminium, gold, silver, indium, ytterbium, a calcium:silver alloy, an aluminum:lithium alloy, or a magnesium:silver alloy.

The device may further comprise any additional features known in the art. Some photovoltaic devices contain interfacial layers between one or both of the anodes and the active material, and such features may be incorporated into the photovoltaic devices of the present application. The devices may be constructed by any techniques known in the art.

Transistors

The compounds of the invention described herein can be suitably used in transistors. The transistors comprise a gate electrode, a gate insulating layer, source and drain electrodes and a channel-forming region, the gate electrode, the gate insulating layer, the source/drain electrodes, and the channel-forming region being disposed on a base, wherein the channel-forming region comprises an electron acceptor material comprising a compound according to Formula 1 or Formula 2. A surface treatment may optionally be applied to the gate dielectric layer. The transistors can be fabricated by methods well known in the art.

ELECTRON ACCEPTOR MATERIALS

The compounds of Formula 1 , which may be suitable for use as an electron acceptor material, generally comprise two or more terminal groups linked together by a conjugated group (D), as follows:

Terminal Conjugated

Group Group

Formula 1

Conjugated group D is selected from one or more optionally substituted, optionally fused, aromatic rings that provide a conjugated pathway between the terminal groups. For example, n may be any integer of 2 to 20, such as any integer of from 2 to 10. In a particular embodiment n is an integer of 2 to 4. For example, when n=2 the compound of Formula 1 would consist of two terminal groups linked together by a bivalent conjugated group D as follows:

Terminal Terminal

Group Group

Formula 1 (n=2)

In a further example, when n=4 the compound of Formula 1 would consist of four terminal groups linked together by a central tetravalent conjugated group D as follows:

from an optionally substituted, optionally fused, 5, 6 or 7 membered carbocyclic or heterocyclic ring. To provide suitable electron acceptor materials or n-type properties, the terminal groups comprise a strong electron withdrawing group to enable for example a LUMO suitable for use with a chosen electron donor material in a photoactive optoelectronic device or fabrication of a transistor. The electron deficient properties of the compounds of Formula 1 , together with strong absorption capabilities in the visible range, make them advantageous candidates as acceptor materials in organic electronic devices. The following embodiments are further described with particular reference to the terminal group and wherein the conjugated group D and integer n are as previously described or as described further herein.

Each terminal group of Formula 1 is generally provided as follows:

Terminal Conjugated

Group Group

Formula 1

wherein

D and n are as described above for Formula 1 ;

A is independently selected for each terminal group from an optionally substituted 5, 6 or 7 membered carbocyclic or heterocyclic ring, which is optionally fused with one or more aryl or heteroaryl rings;

X ¹ is independently selected for each terminal group from O, S and CR ¹ R ² , wherein R ¹ and R ² are each independently selected from CN and C0 ₂ R ³ , R ³ is selected from optionally substituted C C ₁₀ alkyl, optionally substituted C ₂ -C ₁₀ alkenyl, optionally substituted C ₂ -C ₁₀ alkynyl, optionally substituted aryl and arylCrC ₁₀ alkyl.

In one embodiment, X ¹ is independently selected from O, S and C(CN) ₂ . In another embodiment, X ¹ is O.

The core ring A of the terminal group may be fully or partially saturated. For example, ring A may contain one or more double bonds between ring atoms. Ring A may also contain one or more optional substituents and optional fused groups.

Optional substituents of the terminal group A ring may be selected from halo, cyano, carbamoyl, CrC ₂₀ alkyloxycarbonyl, CrC ₂₀ alkyl, CrC ₂₀ haloalkyl, d- C ₂₀ alkylamino, C ₃ -C ₂₀ cycloalkyl, C ₂ -C ₂₀ alkenyl, C ₃ -C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ - C ₂₀ cycloalkynyl, aryl and arylCrC ₂₀ alkyl, heteroaryl and heteroarylCrC ₂₀ alkyl, C C ₂₀ alkyloxy, C ₃ -C ₂₀ cycloalkyloxy and wherein alkyloxycarbonyl, alkyl, haloalkyl, alkylamino, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, alkyloxy and cycloalkyloxy in each occurrence may be optionally substituted, for example further substituted with one or more of halo, OH, NH ₂ , N0 ₂ , COOH.

Optionally fused groups of the terminal group A ring may be optionally substituted aryl or heteroaryl groups. The optionally substituted aryl groups may be monocyclic or polycyclic. The monocyclic aryl groups may be an optionally substituted 6 membered ring, such as benzene. The polycyclic aryl groups may be two or more optionally substituted 6-member rings fused together, such as naphthalene, anthracene, pyrene, tetracene, and pentacene. The heteroaryl groups may be monocyclic or polycyclic. The heteroaryl groups may be selected from 5-membered monocyclic rings, such as thiophene, furan, pyrrole, silole, imidazole, 1 ,3-thiazole, 1 ,3,4-oxadiazole, 1 ,3,4-thiadiazole, or 6 membered rings, such as pyridine and triazine, wherein each ring may be optionally substituted.

In another embodiment, the terminal group may be independently selected from an optionally substituted, optionally fused, 5, 6 or 7 membered carbocyclic or heterocyclic ring according to Formula 2:

Terminal

Group

Formula 2

wherein

D, X ¹ and n are defined according to Formula 1 as described above;

L is selected from N, NR ⁴ , O, S, Se, S0 ₂ , CR ⁴ , CR ⁴ R ⁵ and C=X ² ; wherein X ² is selected from O, S and CR ¹ R ² ;

m is an integer selected from 0, 1 and 2;

G is independently selected from N, NR ⁴ , O, S, Se, S0 ₂ , CR ⁴ , CR ⁴ R ⁵ and C=X ³ ; wherein X ³ is selected from O, S and CR ¹ R ² , and optionally when m is 2 then two G groups are joined together to form an optionally substituted aryl or heteroaryl ring fused to the A ring;

E ¹ and E ² are each independently selected from C=0, C=S, N, NR ⁴ , O, S, S0 ₂ ,

CR ⁴ and CR ⁴ R ⁵ ; and when m is 0 are optionally joined together to form one or more optionally substituted aryl or heteroaryl ring fused to the A ring, and when m is 1 or 2 each of E ¹ and E ² are optionally independently joined with G to form one or more optionally substituted aryl or heteroaryl ring fused to the A ring;

R ¹ and R ² are each independently selected from CN and C0 ₂ R ³ , R ³ is selected from optionally substituted d-Ci ₀ alkyl, optionally substituted C ₂ -Ci ₀ alkenyl, optionally substituted C ₂ -Ci ₀ alkynyl, optionally substituted aryl and arylCi-Ci ₀ alkyl; and

R ⁴ and R ⁵ are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted CrC ₂₀ haloalkyl, optionally substituted C C ₂₀ alkylamino, optionally substituted C ₃ -C ₂₀ cycloalkyl, optionally substituted C ₂ - C ₂ oalkenyl, optionally substituted C ₃ -C ₂ ocycloalkenyl, optionally substituted C ₂ - C ₂ oalkynyl, optionally substituted C ₃ -C ₂₀ cycloalkynyl, optionally substituted aryl and arylCrC ₂₀ alkyl.

In one embodiment, X ¹ is independently selected from O, S and C(CN) ₂ . In another embodiment, X ¹ is O.

L may be selected from N, NR ⁴ , O, S, Se, S0 ₂ , CR ⁴ , CR ⁴ R ⁵ , C=0, C=S and C=C(CN) ₂ , wherein R ⁴ and R ⁵ are defined according to Formula 2 above. L may be selected from N, NH, Nd. ₈ alkyl, O, S, Se, S0 ₂ , C(CN), CH, CH ₂ , Cd. ₁₀ alkyl, CHd. ₁₀ alkyl, C(C ₁ . ₁₀ alkyl) ₂ , C-phenyl, N-phenyl, CCF ₃ , C=0, C=S and C=C(CN) ₂ . L may be selected from C=0, C=S and C=C(CN) ₂ . In one embodiment, L is C=0.

G may be independently selected from N, NR ⁴ , O, S, Se, S0 ₂ , CR ⁴ , CR ⁴ R ⁵ , C=0, C=S and C=C(CN) ₂ , wherein R ⁴ and R ⁵ are defined according to Formula 2 above. G may be selected from N, NH, Nd. ₈ alkyl, O, S, Se, S0 ₂ , C(CN), CH, CH ₂ , Cd. ₁₀ alkyl, CHd. ₁₀ alkyl, C(C ₁ . ₁₀ alkyl) ₂ , C-phenyl, N-phenyl, CCF ₃ , C=0, C=S and C=C(CN) ₂ . G may be selected from C=0, C=S and C=C(CN) ₂ . In one embodiment, G is C=0.

E ¹ and E ² may each be independently selected from C=0, C=S, N, NR ⁴ , O, S, S0 ₂ , CR ⁴ and CR ⁴ R ⁵ ; wherein R ⁴ and R ⁵ are defined according to Formula 2 above. E ¹ and E ² may each be independently selected from C=0, C=S, C=C(CN) ₂ , N, NH, Nd- _! oalkyl, O, S, S0 ₂ , C(CN), Cd. ₁₀ alkyl, CH, CH ₂ , CHd. ₁₀ alkyl, C(d. ₁₀ alkyl) ₂ , C- phenyl, N-phenyl and CCF ₃ . E ¹ and E ² may each be independently selected from NH and NCi-i ₀ alkyl.

When m is 0, E ¹ and E ² may be joined together to form an optionally substituted aryl or heteroaryl ring fused to the A ring, for example an optionally substituted benzene ring fused to the A ring at E ¹ and E ² . When m is 1 or 2 each of E ¹ and E ² may be independently joined with G to form an aryl or heteroaryl ring fused to the A ring, for example a naphthalene group fused to the A ring at E ¹ , E ² and G. The aryl ring may be an optionally substituted monocyclic or polycyclic ring. The monocyclic aryl ring may be an optionally substituted 6 membered ring, such as benzene. The polycyclic aryl ring may be two or more optionally substituted 6-member rings fused together, such as naphthalene, anthracene, pyrene, tetracene, and pentacene, which may each be optionally substituted.

In another embodiment, when m is 1 or 2 and each of E ¹ and E ² are

independently joined with G to form an optionally substituted heteroaryl ring fused to the A ring, the heteroaryl ring may be monocyclic or polycyclic. The optionally substituted heteroaryl ring may be selected from optionally substituted 5-membered monocyclic rings, such as thiophene, furan, pyrrole, silole, imidazole, 1 ,3-thiazole, 1 ,3,4-oxadiazole, 1 ,3,4-thiadiazole, or 6 membered rings, such as pyridine and triazine, which may each be optionally substituted.

In a further embodiment, the terminal group may be independently selected from an optionally substituted 5 membered carbocyclic or heterocyclic ring according to Formula 2a:

Terminal Group

Formula 2a

wherein

E ¹ and E ² are each independently selected from C=0, C=S, N, NR ⁴ , O, S, S0 ₂ , CR ⁴ and CR ⁴ R ⁵ ; and are optionally joined together to form an optionally substituted aryl or heteroaryl ring J that is fused to the A ring; and

D, n, X ¹ , L, R ⁴ and R ⁵ are defined according to Formula 2 as described above.

Various further embodiments of Formula 2a for groups X ¹ , L, E ¹ , E ² , R ¹ , R ² , R ³ , R ⁴ , R ⁵ may be provided as described above.

In one embodiment, the J ring is an optionally substituted aryl ring. For example, E ¹ and E ² may be optionally joined together to form an optionally substituted monocyclic or polycyclic aryl ring J that is fused to the A ring. The optionally substituted monocyclic aryl ring may be a 6 membered ring, such as an optionally substituted benzene. The optionally substituted polycyclic aryl ring may be two or more 6-member rings fused together, such as naphthalene, anthracene, pyrene, tetracene, and pentacene, which may each be optionally substituted. In one embodiment, the aryl ring J is selected from an optionally substituted benzene, napthalene and anthracene. In one particular embodiment, the optional substitution is selected from halo, such as F and CI, cyano, d-C ₂₀ alkyl, C ₃ -C ₂ ocycloalkyl, CrC ₂₀ haloalkyl, C

C ₂₀ alkylamino, aryl and arylCrC ₂₀ alkyl.

In another embodiment, the J ring is an optionally substituted heteroaryl ring. For example, E ¹ and E ² may be optionally joined together to form an optionally substituted monocyclic or polycyclic heteroaryl ring J that is fused to the A ring. The optionally substituted heteroaryl ring may be selected from 5-membered monocyclic rings, such as thiophene, furan, pyrrole, silole, imidazole, 1 ,3-thiazole, 1 ,3,4- oxadiazole, 1 ,3,4-thiadiazole, or 6 membered rings, such as pyridine and triazine, which may each be optionally substituted.

In further embodiments, the optionally substituted, optionally fused, 5 membered carbocyclic or heterocyclic ring of the terminal group A may be selected from one of the following groups:

Formula 2a(iv) Formula 2a(v) wherein for each of the above Formulae 2a(i)-(v):

D and n are as described above for Formula 2 or embodiments thereof;

X ¹ and X ² are each independently selected from O, S and CR ¹ R ² ; wherein R ¹ and R ² are each independently selected from CN and C0 ₂ R ³ , wherein R ³ is selected from CrC ₂₀ alkyl, C ₃ -C ₂ ocycloalkyl, C ₂ -C ₂ oalkenyl, C ₃ - C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkynyl, aryl and arylCrC ₂₀ alkyl, and wherein alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl and arylalkyl in each occurrence may be optionally substituted;

each E ¹ is independently selected from N and CR ⁴ ; each E ² is independently selected from CR ⁴ R ⁵ , NR ⁴ and O; R ⁴ and R ⁵ are each independently selected from hydrogen, halo, cyano, CrC ₂₀ alkyl, C ₃ - C ₂₀ cycloalkyl, C ₂ -C ₂₀ alkenyl, C ₃ -C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ - C ₂ ocycloalkynyl, aryl and arylCrC ₂₀ alkyl, and wherein alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl and arylalkyl in each occurrence may be optionally substituted;

R ⁷ represents one or more optional substituents selected from halo, cyano, carbamoyl, CrC ₂₀ alkyloxycarbonyl, CrC ₂₀ alkyl, CrC ₂₀ haloalkyl, C

C ₂₀ alkylamino, C ₃ -C ₂₀ cycloalkyl, C ₂ -C ₂₀ alkenyl, C ₃ -C ₂₀ cycloalkenyl, C ₂ - C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkynyl, aryl and arylCrC ₂₀ alkyl, heteroaryl and heteroarylCrC ₂₀ alkyl, d-C ₂₀ alkyloxy, C ₃ -C ₂₀ cycloalkyloxy and wherein carbamoyl, alkyl, haloalkyl, alkylamino, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl in each occurrence may be optionally substituted.

In one embodiment, R ⁷ represents one or more optional substituents selected from halo, cyano, carbamoyl, CrC ₂₀ alkyloxycarbonyl, C C ₂₀ alkyl, CrC ₂₀ haloalkyl, C C ₂₀ alkylamino, benzene, naphthalene, anthracene, pyrene, tetracene, pentacene, thiophene, furan, pyrrole, silole, imidazole, 1 ,3-thiazole, 1 ,3,4-oxadiazole, 1 ,3,4- thiadiazole, pyridine and triazine, which may each be optionally substituted and/or provided as a fused substituent. In a further embodiment, R ⁷ represents one or more optional substituents selected from benzene, naphthalene and anthracene, which may be provided as a fused substituent.

In one particular embodiment, a terminal group A may be an optionally substituted, optionally fused, 5 membered carbocyclic group according to Formula 2a(i) as follows:

Terminal Group

Formula 2a(i)

wherein

D, n, R ^{1 ,} R ² , R ³ , R ⁴ and R ⁵ are defined according to Formula 2a as described above or embodiments thereof;

X ¹ and X ² are each independently selected from O, S and CR ¹ R ² ; and R ⁷ represents one or more optional substituents selected from halo, cyano, optionally substituted CrC ₂₀ alkyl, optionally substituted CrC ₂₀ haloalkyl, optionally substituted CrC ₂₀ alkylamino and optionally substituted phenyl; and M represents an optionally substituted aryl or heteroaryl ring that is fused to the benzene ring of the terminal group.

The optionally substituted aryl or heteroaryl ring M that is fused to the benzene ring of the terminal group may be selected from benzene and naphthalene. X ¹ and X ² may each be independently selected from O and C(CN) ₂ .

Some specific examples of 5 membered carbocyclic or heterocyclic rings of the terminal group according to Formula 2a, which may be further optionally substituted, optionally fused, are provided as follows:

In another embodiment, the terminal group may be an optionally substituted, optionally fused, 6 membered carbocyclic or heterocyclic ring according to Formula 2b:

Terminal Group

Formula 2b

wherein

G is selected from N, NR ⁴ , O, S, Se, S0 ₂ , CR ⁴ , CR ⁴ R ⁵ and C=X ³ ;

wherein X ³ is selected from O, S and CR ¹ R ² ; and

E ¹ and E ² are each independently selected from C=0, C=S, N, NR ⁴ , O, S, S0 ₂ , CR ⁴ and CR ⁴ R ⁵ ; and each of E ¹ and E ² are optionally independently joined with G to form an optionally substituted aryl or heteroaryl ring fused to the A ring; and

D, n, X ¹ , L, R ¹ , R ² , R ⁴ and R ⁵ are as described above for Formula 2 or embodiments thereof.

In a further embodiment, the optionally substituted, optionally fused, 6 membered carbocyclic or heterocyclic ring of the terminal group may be selected from one of the following groups:

Terminal Group

Formula 2b(i) Formula 2b(ii)

wherein for each of the above Formulae 2b(i)-(iii):

X ¹ , X ² and X ³ , are each independently selected from O, S and CR ¹ R ² ; E ² and E ³ are each independently selected from N, NR ⁴ , O, S, S0 ₂ , CR ⁴ and CR ⁴ R ⁵ ;

R ¹ and R ² are each independently selected from CN and C0 ₂ R ³ ; R ³ is selected from CrC ₂₀ alkyl, C ₃ -C ₂₀ cycloalkyl, C ₂ -C ₂₀ alkenyl, C ₃ -C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkynyl, aryl and arylCrC ₂₀ alkyl, and wherein alkyl, cycloalkyi, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl and arylalkyi in each occurrence may be optionally substituted; R ⁴ and R ⁵ are each independently selected from hydrogen, halo, cyano, CrC ₂ oalkyl, CrC ₂ ohaloalkyl, Ci-C ₂ oalkylamino, C ₃ -C ₂ ocycloalkyl, C ₂ -C ₂₀ alkenyl, C3-C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkynyl, aryl and arylCrC ₂₀ alkyl, and wherein alkyl, haloalkyl, alkylamino, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl and arylalkyl in each occurrence may be optionally substituted; and

R ⁷ represents one or more optional substituents selected from halo, cyano, C C ₂₀ alkyl, d-C ₂₀ haloalkyl, CrC ₂₀ alkylamino, benzene, naphthalene and anthracene, and wherein each of benzene, naphthalene and anthracene may be optionally fused.

Some specific examples of 6 membered carbocyclic or heterocyclic rings of the termina

An example of a 6 membered carbocyclic ring of the terminal group that is fused with a naphthalene group is p s:

In an embodiment, the terminal group may be an optionally substituted, optionally fused, 7 membered carbocyclic or heterocyclic ring according to Formula 2c as follows:

Formula 2c wherein

X ¹ and X ² are each independently selected from O, S and CR ¹ R ² ;

E ² and E ³ are each independently selected from N, NR ⁴ , O, S, S0 ₂ , CR ⁴ and CR ⁴ R ⁵ ;

R ¹ and R ² are each independently selected from CN and C0 ₂ R ³ , R ³ is selected from d-C ₂₀ alkyl, C ₃ -C ₂ ocycloalkyl, C ₂ -C ₂₀ alkenyl, C ₃ -C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkynyl, aryl and arylCrC ₂₀ alkyl, and wherein alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl and arylalkyl in each occurrence may be optionally substituted;

R ⁴ and R ⁵ are each independently selected from H, halo, cyano, C C ₂₀ alkyl, CrC ₂₀ haloalkyl, d-C^alkylamino, C ₃ -C ₂₀ cycloalkyl, C ₂ -C ₂₀ alkenyl, C ₃ - C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkynyl, aryl and arylCrC ₂₀ alkyl, and wherein alkyl, haloalkyl, alkylamino, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl and arylalkyl in each occurrence may be optionally substituted; and

R ⁷ represents one or more optional substituents selected from halo, cyano, CrC ₂₀ alkyl, CrC ₂₀ haloalkyl, CrC ₂₀ alkylamino, benzene, naphthalene and anthracene, and wherein each of benzene, naphthalene and anthracene may be optionally fused.

Some specific examples of 7 membered carbocyclic or heterocyclic rings of the termina

Conjugated Group D

The conjugated group D provides a conjugated π bond system that has at least one conjugated pathway between at least two terminal groups. The exocyclic methylene group of the terminal A group provides a conjugation link to the conjugated system in the D group. The conjugated group D may be one or more optionally substituted, optionally fused, unsaturated rings joined or fused together to provide the conjugated π bond system. For example, the unsaturated rings of the D group may be selected from one or more aryl and heteroaryl groups. The D group provides a conjugated system of overlapping π bonds along the length of the aryl and/or heteroaryl groups to the electron withdrawing X=C-C=CH- group in the terminal group A ring.

The conjugated systems for the D group, including any substituents thereof, are selected to provide advantageous properties including solubility and crystallinity properties as well as suitable and preferred HOMO/LUMO energy levels of the compounds. The HOMO/LUMO energy levels can be modified by selecting particular functional groups that provide advantageous electronic properties for a semiconductor material, for example enabling the electron accepting semiconductor material to more efficiently absorb sunlight and transport electrons.

The D group may have from 5 to 100 ring atoms, from 5 to 60 ring atoms, from 5 to 50 ring atoms, from 5 to 30 ring atoms, or from 5 to 20 ring atoms. The D group may consist of one or more aromatic rings, for example at least 2 aromatic rings, at least 4 aromatic rings, at least 6 aromatic rings, or at least 8 aromatic rings. The D group may consist of 20 aromatic rings or less, 15 aromatic rings or less, or 10 aromatic rings or less. For example, the D group may consist of any number or range of rings selected from the following: 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, wherein at least 1 of the rings is aromatic and there is provided at least one conjugated pathway connecting the terminal groups. In one embodiment, the conjugated group D contains 1 to 15 rings wherein at least 1 of the rings is aromatic and there is provided at least one conjugated pathway connecting the terminal groups. In another embodiment, the conjugated group D contains 1 to 10 rings wherein at least 1 of the rings is aromatic and there is provided at least one conjugated pathway connecting the terminal groups.

The D group may be substituted. The substituents may be provided to modify the solid state structure or crystallinity of the material. It will be appreciated that aromatic groups are essentially planar and provide good stacking arrangement of individual compounds in a solid material, which provides an advantage by enabling electrons to be conducted through the stacked π system of the material. However, it may be advantageous to restrict a high degree of crystallinity in the material to facilitate processing, for example to provide the material with a certain degree of solubility in relation to fabrication by solution processing, such as spin coating of thin films of the material.

The D group may contain one or more vinyl groups in linear sequence with a aryl or heteroaryl group, which may provide the conjugated pathway between at least two terminal groups. The one or more vinyl groups may be provided in a carbocyclic or heterocyclic group, such as an unsaturated ring. The carbocyclic or heterocyclic group may be a 5 or 6 membered ring.

The D group may be provided by one or more optionally substituted, optionally fused, aryl and/or heteroaryl groups that are joined or fused together to provide the conjugated pathway. The optionally substituted, optionally fused, aryl and/or heteroaryl groups may be formed from one or more 5, 6 or 7 membered rings. The D group may include optionally substituted, optionally fused, carbocyclic or heterocyclic groups. In one embodiment, the D group is one or more optionally substituted, optionally fused, aryl groups. The optionally substituted aryl groups may be monocyclic or polycyclic. The optionally substituted monocyclic aryl groups may be a 6 membered ring, such as optionally substituted benzene. The optionally substituted polycyclic aryl groups may be two or more 6-member rings fused together, such as naphthalene, anthracene, pyrene, tetracene, and pentacene, which may each be optionally substituted. The polycyclic aryl groups may be two or more 6 member rings joined together, such as biphenyl, or two or more fused rings that are joined together, such as fluorene and perylene, which may each be optionally substituted. In one embodiment, the D group is selected from one or more optionally substituted, optionally fused, heteroaryl groups. The optionally substituted heteroaryl groups may be monocyclic or polycyclic. The optionally substituted heteroaryl groups may be selected from 5-membered monocyclic rings, such as thiophene, furan, pyrrole, silole, imidazole, 1 ,3-thiazole, 1 ,3,4-oxadiazole, 1 ,3,4-thiadiazole, or 6 membered rings, such as pyrazine, pyridine and triazine, which may each be optionally substituted. The heteroaryl groups may be polycyclic rings, which may contain fused or joined aryl groups, such as benzothiadiazole and carbazole, which may each be optionally substituted.

In one particular embodiment, the D group has 5 to 80 ring atoms formed from one or more groups selected from benzene, naphthalene, thiophene, furan, biphenyl and fluorene, that are joined or fused together to provide the conjugated π bond system.

The D group, or aromatic rings or groups thereof, may be substituted as herein described with one or more optional substituents. The optional substituents may be selected from halo, cyano, CrC ₂₀ alkyl, CrC ₂ ohaloalkyl, CrC ₂₀ alkylamino, C ₃ - C ₂ ocycloalkyl, C ₂ -C ₂₀ alkenyl, C ₃ -C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkynyl, C C ₂₀ alkylsilyl, C ₂ -C ₂₀ alkenylsilyl, C ₂ -C ₂₀ alkynylsilyl, aryl, arylCi_C ₂₀ alkyl, heteroaryl and heteroarylCi-C ₂ oalkyl, and wherein alkyl, haloakyl, alkylamino, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, alkylsilyl, alkenylsilyl, alkynylsilyl, aryl, arylalkyl, heteroaryl and heteroarylalkyl, in each occurrence may be optionally substituted. In one embodiment, the substituents are selected from Ci_ ₂₀ alkyl, Ci- ₂₀ alkylamino and d. ₂₀ alkylsilyl, wherein each may be optionally with halo, OH, CN, NH ₂ and COOH. In another embodiment, the substituents are selected from C ₄ . ₁₂ alkyl, C^oalkylamino and C ₄ . ₁₂ alkylsilyl. In a further embodiment, the substituents are selected from C ₄ . ₁₂ alkyl.

The D group may be provided by a conjugated group that is linked to each of the terminal groups via an unsaturated 5-membered cyclic group, such as one or more thiophene groups.

In another embodiment, the rings or aromatic rings are provided by monocyclic or polycyclic 6 membered aryl or heteroaryl rings. In another embodiment, at least one of the rings or aromatic rings is carbocyclic. In another embodiment, the rings or aromatic rings are provided by a heterocyclic ring containing heteroatoms selected from at least one of N and Si.

The aromatic rings for the conjugated group D may be provided by one or more optionally substituted, optionally fused, carbocyclic and/or heterocyclic aromatic rings that are joined together, fused together, or a combination thereof, to provide the conjugated pathway. In another embodiment, the aromatic rings for the conjugated group D comprise at least one optionally substituted, optionally fused, heterocyclic aromatic ring, and wherein the rings are joined together, fused together, or a combination thereof, to provide the conjugated pathway.

In one embodiment, at least one optionally substituted, optionally fused, heterocyclic aromatic ring is joined to each terminal group. The conjugated group D may be provided by a single optionally substituted, optionally fused, heterocyclic aromatic ring. The conjugated group D may be provided by two optionally substituted heterocyclic aromatic rings joined together by a bond. The conjugated group D may be provided by three optionally substituted heterocyclic aromatic rings, one of which is a fused heterocyclic ring that is independently joined to each of the two other

heterocyclic rings by a bond.

In another embodiment, the aromatic rings for the conjugated group D are provided by at least one optionally substituted, optionally fused, carbocyclic aromatic ring and at least one optionally substituted, optionally fused, heterocyclic aromatic ring, wherein the rings are joined together, fused together, or a combination thereof, to provide the conjugated pathway. ln another embodiment, the carbocyclic aromatic rings of the D group may be independently selected from benzene, naphthalene, biphenyl and fluorene, and the heterocyclic aromatic rings may be independently selected from thiophene and furan, and wherein each ring is optionally substituted. In a particular embodiment, the carbocyclic aromatic rings may be selected from fluorene, and the heterocyclic aromatic rings may be selected from thiophene, and wherein each group is optionally substituted.

In another embodiment, the conjugated group D is a group according to

Formula 3:

Formula 3

wherein

p is independently selected from an integer of 0 to 15;

Z ¹ is selected from O, S, Se, S0 ₂ , NR ¹² and CR ¹² R ¹³ ;

Z ² and Z ³ are each independently selected from N and CR ¹² ;

R ¹² and R ¹³ are each independently selected from hydrogen, halo, cyano, optionally substituted CrC ₂₀ alkyl, optionally substituted C ₂ -C ₂ oalkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted CrC ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ -C ₂₀ alkynylsilyl; and Ar is selected from one or more optionally substituted, optionally fused, carbocyclic or heterocyclic group that provides at least one conjugated pathway between at least two terminal groups.

It will be appreciated that since p may be 0, the unsaturated 5-membered cyclic group defined in Formula 3 by p, Z ¹ , Z ² and Z ³ , is an optional group, which provides a link between a terminal group and the Ar group. In other words, when p is 0 the conjugated D group is provided by the Ar group, and the Ar group may be defined according to any of the embodiments described herein for the D group.

In an embodiment, Z ¹ is selected from O and S. In another embodiment, Z ² and Z ³ are each independently selected from N and CCrC ₂₀ alkyl. / ^' . Bivalent Linked Conjugated Groups

In an embodiment, when n= 2 (i.e. compounds having two terminal groups), the D group or Ar group may be one or more optionally substituted bivalent linking groups selected from the following groups:

Formula 4 Formula 7

Formula 12 Formula 13 Formula 14 wherein

Q ¹ and Q ² are each independently selected from CR ¹⁴ , N and SiR ¹⁵ ;

each Q ³ , Q ⁴ and Q ⁵ , is independently selected from C=0, C=S, CR ¹⁴ R ¹⁵ , S, Se,

S0 ₂ , O, NR ¹⁴ and SiR ¹⁴ R ¹⁵ ;

Q ⁶ , Q ⁷ , Q ⁸ , Q ⁹ , Q ¹⁰ and Q ¹¹ , are each independently selected from CR ¹⁴ , N, SiR ¹⁴ , C=0, C=S, CR ¹⁴ R ¹⁵ , S, Se, S0 ₂ , O, NR ¹⁴ and SiR ¹⁴ R ¹⁵ ;

R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, halo, cyano, optionally substituted d-C ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted CrC ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ -C ₂₀ alkynylsilyl; and

R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted CrC ₂₀ alkylamino, optionally substituted C ₂ -C ₂ oalkenyl, optionally substituted C ₂ -C ₂ oalkynyl, optionally substituted CrC ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ - C ₂₀ alkynylsilyl.

A specific example of a conjugated group according to Formula 4 is provided follows:

Formula 4a

wherein R ⁸ and R ⁹ are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted CrC ₂₀ alkylamino, optionally substituted C ₂ -C ₂₀ alkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted d-C ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ - C ₂₀ alkynylsilyl.

Some specific examples of conjugated groups according to Formula 5 are provided as follows:

wherein

R ⁸ and R ⁹ are each independently selected from hydrogen, halo, CN, optionally substituted C C ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂₀ alkynyl.

For a conjugated group according to Formula 6, in another embodiment there is provided a bivalent linking grou as follows:

Formula 6 Q is selected from C=0, C=S, CR ^I4 R ^IS , S, Se, S0 ₂ , O, NR and SiR > 1 ^l 4 ⁴ _D R15. R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, halo, cyano, optionally substituted CrC ₂₀ alkyl, optionally substituted C ₂ -C ₂ oalkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted CrC ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ -C ₂₀ alkynylsilyl; and

R ⁸ and R ⁹ are each independently selected from hydrogen, halo, CN, optionally substituted C C ₂₀ alkyl, optionally substituted d-C^alkylamino, optionally substituted C ₂ -C ₂₀ alkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted C

C ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ - C ₂₀ alkynylsilyl.

In a further embodiment, Q ³ is selected from CR ¹⁴ R ¹⁵ , NR ¹⁴ and SiR ¹⁴ R ¹⁵ . In one particular embodiment, Q ³ is selected from CR ¹⁴ R ¹⁵ , wherein R ¹⁴ and R ¹⁵ are defined as above. In a further embodiment, R ¹⁴ and R ¹⁵ are each independently selected from C ₄ . ₁₂ alkyl and C ₄ . ₁₂ cycloalkyl; and R ⁸ and R ⁹ are each independently selected from H and CrC ₂₀ alkyl.

Some specific examples of conjugated groups according to Formula 6 are provided as follows:

Formula 6a Formula 6b Formula 6c

Formula 6d Formula 6e

wherein R ¹⁴ , R ¹⁵ , R ⁸ and R ⁹ , are each independently selected from hydrogen, optionally substituted CrC ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂₀ alkynyl.

An example of a conjugated group according to Formula 8 is provided as follows:

Formula 8a

wherein R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, optionally substituted d-C ₂₀ alkyl, optionally substituted C ₂ -C ₂ oalkenyl and optionally substituted C ₂ -C ₂₀ alkynyl.

An example of a conjugated group according to Formula 10 is provided as follows:

Formula 10a

wherein R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ _, R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, optionally substituted CrC ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂₀ alkynyl.

An example of a conjugated group according to Formula 1 1 is provided as follows:

Formula 1 1a

wherein R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ , are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted CrC ₂₀ alkylamino, optionally substituted C ₂ -C ₂₀ alkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted CrC ₂ oalkylsilyl, optionally substituted C ₂ -C ₂ oalkenylsilyl and optionally substituted C ₂ -C ₂ oalkynylsilyl.

For a conjugated group according to Formula 12, in another embodiment there is provided a bivalent linking group as follows:

Formula 12

Q ¹ and Q ² are each independently selected from CR ¹⁴ , N and SiR ¹⁴ ;

Q ⁶ and Q ⁹ are each independently selected from CR ¹⁴ , N, SiR ¹⁴ ;

Q ⁷ and Q ⁸ are each independently selected from C=0, C=S, CR ¹⁴ R ¹⁵ , S, Se, S0 ₂ , O, NR ¹⁴ and SiR ¹⁴ R ¹⁵ ;

R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, halo, CN, optionally substituted C C ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂₀ alkynyl.

In a further embodiment, Q ⁶ and Q ⁹ are each selected from CH. In a further embodiment, Q ⁷ and Q ⁸ are each selected from S. In a further embodiment, Q ¹ and Q ² are each independently selected from CR ¹⁴ , NR ¹⁴ and SiR ¹⁴ , wherein R ¹⁴ is defined as above. In one particular embodiment, Q ² is selected from CH, and Q ¹ is selected from CR ¹⁴ , NR ¹⁴ and SiR ¹⁴ , wherein R ¹⁴ is defined as above. In yet a further embodiment, R ¹⁴ is selected from C ₄ _i ₂ alkyl and C ₄ _i ₂ cycloalkyl.

An example of a conjugated group according to Formula 12 is provided as follows:

Formula 12a

wherein R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ , are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted CrC ₂₀ alkylamino, optionally substituted C ₂ -C ₂₀ alkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted d-C ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ -C ₂₀ alkynylsilyl.

Some specific examples of conjugated groups according to Formula 13 are provided as follows:

Formula 13a Formula 13b Formula 13c wherein R ⁸ , R ⁹ , R ¹⁴ and R ¹⁵ , are each independently selected from hydrogen, halo, CN, optionally substituted d-C ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂ oalkynyl.

For a conjugated group according to Formula 14, in another embodiment there is provided a bivalent linking grou

Formula 14

wherein

Q ¹ and Q ² are each independently selected from CR ¹⁴ , N and SiR ¹⁴ ;

Q ⁶ and Q ⁸ are each independently selected from CR ¹⁴ , N, SiR ¹⁴ ;

Q ⁷ and Q ⁹ are each independently selected from C=0, C=S, CR ¹⁴ R ¹⁵ , S, Se, S0 ₂ , O, NR ¹⁴ and SiR ¹⁴ R ¹⁵ ; and

R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂₀ alkynyl.

In a further embodiment, Q ⁶ and Q ⁸ are each selected from CH. In a further embodiment, Q ⁷ and Q ⁹ are each selected from S. In a further embodiment, Q ¹ and Q ² are each independently selected from CR ¹⁴ , N and SiR ¹⁴ , wherein R ¹⁴ is defined as above. In one particular embodiment, Q ² is selected from CH, and Q ¹ is selected from CR ¹⁴ , N and SiR ¹⁴ , wherein R ¹⁴ is defined as above. In yet a further embodiment, R ¹⁴ is selected from C ₄ . ₁₂ alkyl and C ₄ . ₁₂ cycloalkyl.

An example of a conjugated group according to Formula 14 is provided as follows:

Formula 14a

wherein R and R are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted CrC ₂ oalkylamino, optionally substituted C ₂ -C ₂ oalkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted CrC ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ - C ₂₀ alkynylsilyl.

/ ^' / ^' . Tetravalent Linked Conjugated Groups

In an embodiment, when n= 4 (i.e. compounds having four terminal groups), the D group or Ar group may be an optionally substituted bivalent linking group selected from any of the following groups:

Formula 15

Formula 16

Formula 18

wherein

each Q ³ , Q ⁴ and Q ⁵ , is independently selected from C=0, C=S, CR ¹⁴ R ¹⁵ , S, Se, S0 ₂ , O, NR ¹⁴ and SiR ¹⁴ R ¹⁵ ; R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂ oalkynyl;

R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ , are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted CrC ₂₀ alkylamino, optionally substituted C ₂ -C ₂₀ alkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted CrC ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ - C ₂₀ alkynylsilyl.

/ ^' / ^' / ^' . Unsaturated 5-membered cyclic groups as optional linking groups

The D group may be provided by a conjugated group that is linked to each of the terminal groups via an unsaturated 5-membered cyclic group, such as one or more thiophene groups.

In another embodiment, the conjugated group D is a group according to

Formula 3:

Formula 3

wherein

p is independently selected from an integer of 0 to 15;

Z ¹ is selected from O, S, Se, S0 ₂ , NR ¹² and CR ¹² R ¹³ ;

Z ² and Z ³ are each independently selected from N and CR ¹² ;

R ¹² and R ¹³ are each independently selected from hydrogen, halo, cyano, optionally substituted C C ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted CrC ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ -C ₂₀ alkynylsilyl; and

Ar is selected from one or more optionally substituted, optionally fused, carbocyclic or heterocyclic group that provides at least one conjugated pathway between at least two terminal groups.

It will be appreciated that since p may be 0, the unsaturated 5-membered cyclic group defined in Formula 3 by p, Z ¹ , Z ² and Z ³ , is an optional group, which provides a link between a terminal group and the Ar group. In other words, when p is 0 the conjugated D group is provided by the Ar group, and the Ar group may be defined according to any of the embodiments described herein for the D group.

In an embodiment, Z ¹ is selected from O and S. In another embodiment, Z ² and Z ³ are each independently selected from N and CCi-C ₂ oalkyl.

It will be appreciated that since the compounds of Formula 1 and Formula 2 have at least two terminal groups, the Ar group in Formula 3 may be linked to each terminal group by one or more of the unsaturated 5-membered rings defined by p, Z ¹ , Z ² and Z ³ .

For example, in a further embodiment of Formula 2 when n=2 (i.e. two terminal groups), the D group may be provided by a bivalent linking group according to Formula 19 as follows:

wherein

p ¹ and p ² are each independently selected from an integer of 0 to 15; and Z ¹ , Z ² , Z ³ and Ar, are defined herein as for Formula 3.

The integer p, which includes integers for p ¹ , p ² , p ³ etc, may each be

independently selected from any of the following integers: 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15. In one embodiment p is an integer between 1 and 10. In another embodiment, p is 1 , 2 or 3. In a particular embodiment, p is 1. In another embodiment, Z ¹ is S or O and Z ² and Z ³ are both CH. For example, in one embodiment Formula 3 provides a group selected from an optionally substituted thiophene and furan group.

The Ar group according to Formula 3 may be provided by any of the

embodiments described above for the conjugated D group. For example, the Ar group may be provided by a group according to any of Formulae 4 to 14, including any embodiments thereof described above.

For example, where Ar is a conjugated group of Formula 6 above, a bivalent linked conjugated group in accordance with Formula 19 ma be provided as follows:

wherein

p ¹ and p ² are each independently selected from an integer of 0 to 10;

Q ³ , Q ⁴ and Q ⁵ are each independently selected from C=0, C=S, CR ¹⁴ R ¹⁵ , S, Se, S0 ₂ , O, NR ¹⁴ and SiR ¹⁴ R ¹⁵ ;

R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, halo, CN, optionally substituted d-C ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂₀ alkynyl;

R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ , are each independently selected from hydrogen, halo, CN, optionally substituted C C ₂₀ alkyl, optionally substituted d-C^alkylamino, optionally substituted C ₂ -C ₂₀ alkenyl, optionally substituted C ₂ -C ₂₀ alkynyl, optionally substituted CrC ₂₀ alkylsilyl, optionally substituted C ₂ -C ₂₀ alkenylsilyl and optionally substituted C ₂ - C ₂₀ alkynylsilyl.

In a further embodiment, Q ⁴ and Q ⁵ are S, and Q ³ is selected from CR ¹⁴ R ¹⁵ , NR ¹⁴ and SiR ¹⁴ R ¹⁵ , wherein R ¹⁴ and R ¹⁵ are defined as above. In one particular embodiment, Q ³ is selected from CR ¹⁴ R ¹⁵ , wherein R ¹⁴ and R ¹⁵ are defined as above. In a further embodiment, R ¹⁴ and R ¹⁵ are each independently selected from C ₄ _i ₂ alkyl and C ₄ _i ₂ cycloalkyl. In a further embodiment, p ¹ and p ² are each independently selected from an integer of 1 to 5.

Further examples of groups according to embodiments of Formula 19, wherein p ¹ and p ² are both 1 , are provided as follows:

wherein R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, halo, CN, optionally substituted C C ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂₀ alkynyl. In one particular embodiment R ¹⁴ and R ¹⁵ are each independently selected from C ₄ -C ₁₂ alkyl.

Further examples of groups according to embodiments of Formula 19, where p ¹ and p ² are both 1 , and where Ar is a conjugated group according to various specific groups of Formula 4 to 14 as described above, may be provided by a bivalent linked conjugated group as follows:

R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, halo, CN, optionally substituted CrC ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂ oalkynyl.

In another example, in a further embodiment of Formula 2 when n=4 (i.e. four terminal groups), the D group may be provided by a tetravalent linking group according to Formula 20 as follows:

wherein p ¹ , p ² , p ³ and p ⁴ , are each independently selected from an integer of 0 to 15; and Z ¹ , Z ² , Z ³ and Ar, are defined herein as for Formula 3. In another embodiment, where Ar is a conjugated group according to Formula 19 as described above, an example of a tetravalent linked conjugated group also in accordance with Formula 20 may be provided as follows:

In another embodiment, the D group may be a group according to Formula 24:

Formula 24

wherein

p is independently selected from an integer of 0 to 15;

Z ¹ is selected from O, S, Se, S0 ₂ , NR ¹² and CR ¹² R ¹³ ;

Z ² and Z ³ are each independently selected from N and CR ¹² ;

R ¹² and R ¹³ are each independently selected from hydrogen, halo, cyano, C C ₂₀ alkyl, C ₃ -C ₂ ocycloalkyl, C ₂ -C ₂ oalkenyl, C ₃ -C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ - C ₂₀ cycloalkynyl, CrC ₂₀ alkylsilyl, C ₂ -C ₂₀ alkenylsilyl and C ₂ -C ₂₀ alkynylsilyl, and wherein alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, alkylsilyl, alkenylsilyl and alkynylsilyl, in each occurrence may be optionally substituted. In an embodiment, Z ¹ is selected from O and S. In another embodiment, Z ² and Z ³ are each independently selected from N and CCrC ₂₀ alkyl.

In another embodiment when n is 2, the D group of Formula 24 may be provided by a group according to Formula 24a:

wherein

Each Z ¹ is independently selected from O, S, Se, S0 ₂ , NR ¹² and

CR ¹² R ¹³ ; Each Z ² and Z ³ are independently selected from N and CR ¹² ;

R ¹² and R ¹³ are each independently selected from hydrogen, halo, cyano, C C ₂₀ alkyl, C ₃ -C ₂ ocycloalkyl, C ₂ -C ₂ oalkenyl, C ₃ -C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ - C ₂₀ cycloalkynyl, CrC ₂₀ alkylsilyl, C ₂ -C ₂₀ alkenylsilyl and C ₂ -C ₂₀ alkynylsilyl, and wherein alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, alkylsilyl, alkenylsilyl and alkynylsilyl, in each occurrence may be optionally substituted.

PARTICULAR COMPOUNDS OF FORMULA 1

The compounds of Formula 1 can exist as one or more stereoisomers. The various stereoisomers can include enantiomers, diastereomers and geometric isomers. Those skilled in the art will appreciate that one stereoisomer may be more active than the other(s). In addition, the skilled person would know how to separate such

stereoisomers. Accordingly, the present invention comprises mixtures, individual stereoisomers, and optically active mixtures of the compounds described herein.

For example, although Formula 1 has been drawn as the (E)-isomer, it should be understood that the compounds of the present invention may also exist as (Z)- isomers, or mixtures thereof, and therefore, such isomers or mixtures thereof are clearly included within the present invention.

In one embodiment, there is provided a compound of Formula 2 or

stereoisomers thereof:

Terminal

Group

Formula 2

wherein

n is an integer of 2 to 20;

X ¹ is independently selected for each terminal group from O, S and CR ¹ R ² ;

L is selected from N, NR ⁴ , O, S, Se, S0 ₂ , CR ⁴ , CR ⁴ R ⁵ and C=X ² ; wherein X ² is selected from O, S and CR ¹ R ² ;

m is an integer selected from 0, 1 and 2;

G is independently selected from N, NR ⁴ , O, S, Se, S0 ₂ , CR ⁴ , CR ⁴ R ⁵ and C=X ³ ; wherein X ³ is selected from O, S and CR ¹ R ² , and optionally when m is 2 then two G groups are joined together to form an optionally substituted aryl or heteroaryl ring fused to the A ring;

E ¹ and E ² are each independently selected from C=0, C=S, N, NR ⁴ , O, S, S0 ₂ , CR ⁴ and CR ⁴ R ⁵ ; and when m is 0 are optionally joined together to form one or more optionally substituted aryl or heteroaryl ring fused to the A ring, and when m is 1 or 2 each of E ¹ and E ² are optionally independently joined with G to form one or more optionally substituted aryl or heteroaryl ring fused to the A ring;

R ¹ and R ² are each independently selected from CN and C0 ₂ R ³ , R ³ is selected from optionally substituted C C ₁₀ alkyl, optionally substituted C ₂ -C ₁₀ alkenyl, optionally substituted C ₂ -C ₁₀ alkynyl, optionally substituted aryl and aryld-C ₁₀ alkyl; and

R ⁴ and R ⁵ are each independently selected from hydrogen, halo, CN, optionally substituted C C ₂₀ alkyl, optionally substituted CrC ₂₀ haloalkyl, optionally substituted C C ₂₀ alkylamino, optionally substituted C ₃ -C ₂₀ cycloalkyl, optionally substituted C ₂ - C ₂₀ alkenyl, optionally substituted C ₃ -C ₂₀ cycloalkenyl, optionally substituted C ₂ - C ₂₀ alkynyl, optionally substituted C ₃ -C ₂₀ cycloalkynyl, optionally substituted aryl and arylCrC ₂₀ alkyl.

D is a conjugated group that provides at least one conjugated pathway between at least two terminal groups and which is selected from one or more optionally substituted, optionally fused, rings provided that at least one of the rings is aromatic, and which is selected from a grou ula 3

Formula 3

wherein

p is independently selected from an integer of 0 to 15;

Z ¹ is independently selected from O, S, Se, S0 ₂ , NR ¹² , CR ¹² R ¹³ and SiR ¹² R ¹³ ;

Z ² and Z ³ are each independently selected from N and CR ¹² ;

Ar is selected from an optionally substituted, optionally fused, aryl or heteroaryl group.

In an embodiment, the following compounds are provisos to the compounds of the above embodiment:

when n is 2, m is 1 , X ¹ is O, L is C=0, and G is C=X ² , E ¹ and E ² are NH, NCH ₃ or N(C ₂ H ₅ ), p is 0, and Ar is selected from optionally substituted, optionally fused, thiophene groups, then at least two thiophene groups are fused together; or

when n is 2, m is 1 , X ¹ is O, L is C=0, and G is C=X ² , E ¹ and E ² are NH, NCH ₃ or N(C ₂ H ₅ ), p is at least 1 , each Z ¹ is S, each Z ² and Z ³ are CH, and Ar is selected from optionally substituted, optionally fused, thiophene groups, then at least two thiophene groups are fused together; or

when n is 2, m is 0 and G is absent, E ¹ and E ² are C=S, N(C ₂ H ₅ ) or joined together to form a benzene ring fused to the A ring, L is S, S0 ₂ or C=X ² , X ¹ and X ² are O or C(CN) ₂ , p is 0, and Ar is selected from optionally substituted, optionally fused, thiophene groups, then at least two thiophene groups are fused together; or

when n is 2, m is 0 and G is absent, E ¹ and E ² are C=S, N(C ₂ H ₅ ) or joined together to form a benzene ring fused to the A ring, L is S, S0 ₂ or C=X ² , X ¹ and X ² are O or C(CN) ₂ , p is at least 1 , each Z ¹ is S, each Z ² and Z ³ are CH, and Ar is selected from optionally substituted, optionally fused, thiophene groups, then at least two thiophene groups are fused together; or

when n is 2, m is 0 and G is absent, E ¹ and E ² are joined together to form a benzene ring fused to the A ring, L is S0 ₂ or C=X ² , X ¹ and X ² are O or C(CN) ₂ , and Ar is selected from one or more benzene groups, then p is at least 1.

It will be appreciated that compounds of Formula 2 as described in the above embodiments may be provided by various further embodiments as previously described herein for the terminal A groups and conjugated group D or Ar, including the groups n, X ¹ , L, E ¹ , E ² , m and G.

In one embodiment, p may be selected from 1 to 15, preferably 1 to 5. In another embodiment, Ar may be selected from optionally substituted, optionally fused, aryl groups. In one embodiment, the Ar group is provided by monocyclic or polycyclic 6 membered aryl or heteroaryl rings. In another embodiment, the Ar group may comprise at least one carbocyclic ring.

In another embodiment, the aromatic rings for the conjugated group Ar are provided by at least one optionally substituted, optionally fused, carbocyclic aromatic ring and at least one optionally substituted, optionally fused, heterocyclic aromatic ring, wherein the rings are joined together, fused together, or a combination thereof, to provide the conjugated pathway.

In another embodiment, the carbocyclic aromatic rings of the Ar group may be independently selected from benzene, naphthalene, biphenyl and fluorene, and the heterocyclic aromatic rings may be independently selected from thiophene and furan, and wherein each ring is optionally substituted. In a particular embodiment, the carbocyclic aromatic rings may be selected from fluorene, and the heterocyclic aromatic rings may be selected from thiophene, and wherein each group is optionally substituted.

In another embodiment, Z ¹ is selected from O, Se, S0 ₂ , NR ¹² , CR ¹² R ¹³ and SiR ¹² R ¹³ . In a further embodiment, Z ¹ is selected from N and Si.

In another embodiment, when Ar is selected from optionally substituted, optionally fused, thiophene groups, then at least two thiophene groups are fused together.

In one embodiment, in accordance with a compound of Formula 2, and wherein n=2 (i.e. two terminal groups) and the conjugated group D is selected from a group according to Formula 3 and 19, there is provided a compound according to Formula 21 as follo

Terminal Group Conjugated Group Terminal Group

Formula 21

wherein for the conjugated group, p ¹ and p ² are each independently selected from an integer of 0 to 15, and Ar, Z ¹ , Z ² and Z ³ , are each independently selected from any of the groups or embodiments as previously described herein including

embodiments of the forth aspect; and A, X ¹ , L, E ¹ , E ² , G and m, for each terminal group are independently selected from any of the groups or embodiments as previously described herein including embodiments of the forth aspect.

In a further embodiment, in accordance with a compound of Formula 2, and wherein n=4 (i.e. four terminal groups) and the conjugated group D is selected from a group according to Formula 3, there is provided a compound according to Formula 22 as follows:

Formula 22

wherein for the conjugated group, p ¹ , p ² , p ³ and p ⁴ , are each independently selected from an integer of 0 to 15, and Ar, Z ¹ , Z ² and Z ³ , are each independently selected from any of the groups or embodiments as previously described herein including embodiments of the forth aspect; and A, X ¹ , L, E ¹ , E ² , G and m, for each terminal group are independently selected from any of the groups or embodiments as previously described herein including embodiments of the forth aspect.

In a further embodiment example, in accordance with a compound of Formula 2 when n=2 and the conjugated group D is selected from a group according to

Formula 19, there is prov s follows:

Formula 23

wherein

p ¹ and p ² are each independently selected from an integer of 0 to 10;

Q ³ , Q ⁴ and Q ⁵ are each independently selected from C=0, C=S, CR ¹⁴ R ¹⁵ , S, Se, S0 ₂ , O, NR ¹⁴ and SiR ¹⁴ R ¹⁵ ;

R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, halo, cyano, C C ₂ oalkyl, C ₃ -C ₂ ocycloalkyl, C ₂ -C ₂ oalkenyl, C ₃ -C ₂₀ cycloalkenyl, C ₂ -C ₂₀ alkynyl, C ₃ - C ₂₀ cycloalkynyl, d-C ₂₀ alkylsilyl, C ₂ -C ₂₀ alkenylsilyl and C ₂ -C ₂₀ alkynylsilyl, and wherein alkyl, cycloalkyi, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, alkylsilyl, alkenylsilyl and alkynylsilyl, in each occurrence may be optionally substituted; and R ⁸ and R ⁹ each represent one or more optional substituents independently selected from hydrogen, halo, cyano, CrC ₂₀ alkyl, CrC ₂ ohaloalkyl, CrC ₂₀ alkylamino, C ₂ -C ₂ oalkenyl, C ₂ -C ₂₀ alkynyl, CrC ₂₀ alkylsilyl, C ₂ -C ₂₀ alkenylsilyl and C ₂ -C ₂₀ alkynylsilyl.

In one embodiment, Q ⁴ and Q ⁵ are each independently selected from C=0 and C=S. In another embodiment, Q ³ is selected from CR ¹⁴ R ¹⁵ , S, S0 ₂ , O, NR ¹⁴ and

SiR ¹⁴ R ¹⁵ . In another embodiment, R ⁸ , R ⁹ , R ¹⁴ and R ¹⁵ are each independently selected from hydrogen, optionally substituted C C ₂₀ alkyl, optionally substituted C ₂ -C ₂₀ alkenyl and optionally substituted C ₂ -C ₂₀ alkynyl.

Various non-limiting further examples of compounds of the invention are provided as follows:

Compound 2

Compound 4

Compound 5

Compound 6

Compound 7

Compound 10

Compound 13

10

Compound 15

Compound 20

Compound 33

Compound 34

Compound 40

Compound 44

Compound 62

Compound 73

Compound 82

ELECTRON DONOR MATERIALS

The electron donor material may comprise polymers such as regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT), regioregular poly(3-ocylthiophene-2,5-diyl) (P30T), regioregular poly(quarterthiophene) (PQT), a-poly(phenylene ethynylene)- poly(phenylene vinylene) (A-PPE-PPV), poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1 ,4- phenylene vinylene] (MEH-PPV), or poly[2-methoxy-5-(3,7-dimethyloctyloxy)-1 ,4- phenylenevinylene] (MDMO-PPV), or short oligomers of these polymers. Small molecules such as 3,6-bis(5-(benzofuran-2-yl)thiophen-2-yl)-2,5-bis(2- ethylhexyl)pyrrolo[3,4-c]pyrrole-1 ,4(2H,5H)-dione (EH-DPP), 6, 13- bis((triisopropylsilyl)ethynyl)pentacene (TIPS-PEN) or 2-(2,6-bis((E)-4- (diphenylamino)styryl)-4H-pyran-4-ylidene)malononitrile (DPAPM) may also be used as donor materials. Many more examples of electron donor materials can be found in literature reviews on OPVs, for example, LI, Y., Acc. Chem. Res., 2012, 45 (5), pp 723-733, Mishra et al, Angew. Chem. Int. Ed., 2012, 51 , pp 2020-2068, and Beaujuge et al, J. Am. Chem. Soc, 201 1 , 133 (50), pp 20009-2." In one embodiment, the electron donor material is P3HT. ADDITIVES

The thin film or layer comprising the compound of Formula 1 may further comprise one or more additives, such as additional film components, which may include additives beneficial to film formation or film morphology. These additives may be removed from the formed film or layer by evaporation or they may be permanently incorporated into the thin film or layer. Examples of additives are hexadecane, 1 ,8- diiodooctane (DIO), 1 ,8-octanedithiol (ODT), 1-chloronaphthalene, /V-methyl-2- pyrrolidone, diethylene glycol dibutyl ether, polystyrene, or polysiloxanes, or mixtures of the aforesaid additives.

DEVICE COMPONENTS AND CONFIGURATION

Optoelectronic Devices

Optoelectronic photoactive devices, such as organic solar cells, may be prepared in the form of a bilayer device, bulk heterojunction device or blend or hybrid device.

As shown in Figure 1 , a bilayer organic solar cell (1) according to one embodiment of the invention may generally comprise an anode (2), for example as a transparent layer of indium tin oxide on a transparent thin film support (3), and a cathode (4), for example in the form of an adjacent metal cathode. Between the anode and cathode are layers of an electron donor material (or p-conductor) (5), for example P3HT, and an electron acceptor material (6) (or n-conductor), for example a compound of Formula 1. The device may contain multiple layers, and the term "bilayer" should be interpreted as encompassing 2 or more layered devices. The device may be in the form of a single cell, or multiple cells connected in parallel and/or series. The device typically further comprises positive and negative terminals (not illustrated) for connection to an energy storage device or other electrical component(s) or circuit(s).

As shown in Figure 2, a bulk heterojunction organic solar cell (7) according to one embodiment of the invention may generally comprise an anode (2), for example a transparent layer of indium tin oxide supported on a transparent thin film support (3), and a cathode (4), for example in the form of an adjacent metal cathode. Between the anode and cathode is an active material comprising a blend of electron acceptor material (6) (or n-conductor), for example a compound of Formula 1 , and an electron donor (or p-conductor) material (5), for example P3HT. In one embodiment, the concentration of each component (5) and (6) gradually increases when approaching to the corresponding electrode. The device may be in the form of a single cell, or multiple cells connected in parallel and/or series. The device typically further comprises positive and negative terminals (not illustrated) for connection to an energy storage device or other electrical component(s) or circuit(s).

In preparing a photoactive optoelectronic device, such as a solar cell, one configuration comprises providing a thin layer (e.g. about 40 nm layer) of PEDOT/PSS solution on a substrate, for example by spin coating and annealing. For bulk heteroj unction or blend devices, solutions of the organic blends can be deposited onto the PEDOT/PSS layer by spin coating. Advantageous spinning conditions and film thicknesses can be identified for various blends.

Single layers of the organic materials can also be deposited sequentially, for example by thermal evaporation at reduced pressures (e.g. below 2 ^χ ^ 0 ^~6 mbar).

Organic layers may be dissolved in a solvent, such as an organic solvent for example chlorobenezene and 1 ,2-dichlorobenezene. Solutions can be spin coated, for example by using a Laurell WS-650SZ-23NPP Lite single wafer spin processor. Preferred spin parameters may range from 2000-3000 RPM with an acceleration of 6000 RPM. Thin films can be further thermally annealed, for example at 120°C for 10 minutes.

A layer of Ca can also be deposited by thermal evaporation at reduced pressures, for example below 2* 10 ^~7 mbar. A metal layer, such as an Al layer, can be deposited, for example by Angstrom Engineering evaporator at pressures below 2x 10 ^{" 7} mbar. The devices can be annealed, for example on a hotplate in a glovebox.

A small amount of silver paint (Silver Print II , GC electronics, Part no. : 22-023) can also be deposited onto the connection points of the electrodes. Completed devices can be encapsulated with glass and a UV-cured epoxy, for example by using Lens Bond type J-91 and exposing to 254nm UV-light inside a glovebox (H ₂ 0 and 0 ₂ levels both < 1 ppm) for 10 minutes.

In another configuration the structure of the entire device can be inverted and the device fabrication process can commence with a cathode and be completed by the addition of a top anode. In both configurations either or both electrodes may be transparent to the electromagnetic radiation, for example light, that is being detected.

A thin film component for a photoactive optoelectronic device may be prepared by a spin coating process. For example, an active material comprising an electron acceptor material according to the compound of Formula 1 defined above may be spin coated onto a substrate.

A coating process may comprise the steps of: providing a solution comprising a compound of Formula 1 and at least a solvent, optionally an additive and optionally an electron donor material; depositing the solution onto an optionally coated anode or cathode material; and optionally evaporating the solvent from the deposited solution.

The optionally coated anode or cathode material may be provided on a support, such as a glass support. The anode is any material able to conduct holes and inject them into organic layers. The anode may comprise of layers such as poly(ethylene dioxythiophene): polystyrene sulfonic acid (PEDOT:PSS), molybdenum oxide, or poly- aniline:dodecylbenzenesulfonic acid (PANI:DBS) and fluorine tin oxide (FTO), indium tin oxide (ITO), conductive polymer layers or graphene or single-walled carbon nanotubes (SWCNT) or grids or meshes of metals such as gold or silver.The cathode is any material able to conduct electrons and collect them from organic layers. The cathode may comprise of layers such as lithium fluoride, calcium, barium, 2,9-dimethyl- 4,7-diphenyl-1 , 10-phenanthroline (BCP), or aluminium oxide and metals such as aluminium, gold, silver, indium, ytterbium, a calcium:silver alloy, an aluminum:lithium alloy, or a magnesium:silver alloy or graphene or single-walled carbon nanotubes (SWCNT).

It will be appreciated that the solvent is selected to solubilise an appropriate amount of a compound of Formula 1 for solution based processing of thin film components. The solvent is preferably selected form a volatile solvent. The solvent may be an organic solvent. Any suitable solvent can be used to dissolve, and/or disperse a compound of the Formula 1 , provided it is inert and can be removed partly, or completely from the substrate by conventional drying means (e.g. application of heat, reduced pressure, airflow etc.). Suitable organic solvents for processing the semiconductors include, but are not limited to, aromatic or aliphatic hydrocarbons, halogenated such as chlorinated or fluorinated hydrocarbons, esters, ethers and amides, and mixtures thereof. Examples of such solvents are chloroform,

tetrachloroethane, tetrahydrofuran, toluene, tetrahydronaphthalene, anisole, xylene, mesitylene, ethyl acetate, methyl ethyl ketone, dimethyl formamide, chlorobenzene, dichlorobenzene, trichlorobenzene and propylene glycol monomethyl ether acetate (PGMEA). The solution, and/or dispersion is then applied by a method, such as, spin- coating, dip-coating, screen printing, microcontact printing, doctor blading or other solution application techniques known in the art on the substrate to obtain thin films of the semiconducting material.

Transistors

A transistor device includes a gate electrode, a gate insulating layer, source/drain electrodes, and a channel-forming region that are disposed on a base, the channel-forming region may be composed of a semiconductor. Furthermore, such a transistor device can also be configured as any of the bottom gate/bottom contact type field-effect transistor (FET), the bottom gate/top contact type FET, the top gate/bottom contact type FET, and the top gate/top contact type FET which will be described below.

In the case where the semiconductor device is configured as a bottom gate/bottom contact type field-effect transistor (FET), the bottom gate/bottom contact type FET includes (1) a gate electrode disposed on a base, (2) a gate insulating layer disposed on the gate electrode, (3) source/drain electrodes disposed on the gate insulating layer, and (4) a channel-forming region disposed between the source/drain electrodes and on the gate insulating layer. A surface treatment (5) may optionally be applied to the gate insulating layer.

In the case where the transistor device is configured as a bottom gate/top contact type FET, the bottom gate/top contact type FET includes (1) a gate electrode disposed on a base, (2) a gate insulating layer disposed on the gate electrode, (3) a channel-forming region and a channel-forming region extension disposed on the gate insulating layer, and (4) source/drain electrodes disposed on the channel-forming region extension (Figure 6). A surface treatment (5) may optionally be applied to the gate insulating layer.

In the case where the transistor device is configured as a top gate/bottom contact type FET, the top gate/bottom contact type FET includes (1) source/drain electrodes disposed on a base, (2) a channel-forming region disposed between the source/drain electrodes and on the base, (3) a gate insulating layer disposed on the channel-forming region, and (4) a gate electrode disposed on the gate insulating layer.

Furthermore, in the case where the transistor device is configured as a top gate/top contact type FET, the top gate/top contact type FET includes (1) a channel- forming region and a channel-forming region extension disposed on a base, (2) source/drain electrodes disposed on the channel-forming region extension, (3) a gate insulating layer disposed on the source/drain electrodes and the channel-forming region, and (4) a gate electrode disposed on the gate insulating layer.

The base can be composed of a silicon oxide-based material or spin-on glass (SOG); silicon nitride; aluminum oxide; or a metal oxide high dielectric constant insulating film. When the base is composed of such a material, the base may be formed on (or above) a support composed of any of the materials described below. That is, examples of the material for the support and/or a base other than the base described above include organic polymers, such as polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polyvinyl phenol (PVP), polyethersulfone (PES), polyimide, polycarbonate, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN); and mica. When organic polymers are used, the polymeric materials are formed into plastic films, plastic sheets, and plastic substrates having flexibility. By using a base composed of any of such flexible polymeric materials, for example, the resulting field- effect transistor can be built in or integrated into a display device or electronic apparatus having curved surfaces. Other examples of the base include various glass substrates, various glass substrates provided with insulating films on the surfaces thereof, quartz substrates, quartz substrates provided with insulating films on the surfaces thereof, silicon substrates provided with insulating films on the surfaces thereof, and metal substrates composed of various alloys or various metals, such as stainless steel. As a support having electrical insulating properties, an appropriate material may be selected from the materials described above. Other examples of the support include conductive substrates, such as a substrate composed of a metal (e.g., gold), a substrate composed of highly oriented graphite, and a stainless steel substrate. Furthermore, depending on the configuration and structure of the

semiconductor device, the semiconductor device may be provided on a support. Such a support can be composed of any of the materials described above.

Examples of the material constituting the gate electrode, source/drain electrodes, and interconnect lines include metals, such as platinum, gold, palladium, chromium, molybdenum, nickel, aluminum, silver, tantalum, tungsten, copper, titanium, indium, and tin, alloys containing these metal elements, conductive particles composed of these metals, conductive particles composed of alloys containing these metals, and conductive materials, such as impurity-containing polysilicon. A stacked structure including layers containing these elements may be employed. Furthermore, as the material constituting the gate electrode, source/drain electrodes, and interconnect lines, an organic material (conductive polymer), such as poly(3,4- ethylenedioxythiophene)/polystyrene sulfonic acid [PEDOT/PSS], may be mentioned. The materials constituting the gate electrode, source/drain electrodes, and

interconnect lines may be the same or different.

Examples of the method for forming the gate electrode, source/drain electrodes, and interconnect lines include, although depending on the materials constituting them, physical vapor deposition (PVD) methods; various chemical vapor deposition (CVD) methods, such as MOCVD; spin coating methods; various printing methods, such as screen printing, ink-jet printing, offset printing, reverse offset printing, gravure printing, and microcontact printing; various coating methods, such as air- doctor coating, blade coating, rod coating, knife coating, squeeze coating, reverse roll coating, transfer roll coating, gravure coating, kiss coating, cast coating, spray coating, slit orifice coating, calender coating, and dipping; stamping methods; lift-off methods; shadow-mask methods; plating methods, such as electrolytic plating, electroless plating, or a combination of both; and spraying methods. As necessary, these methods may be combined with patterning techniques. Furthermore, examples of PVD methods include (a) various vacuum deposition methods, such as electron beam heating, resistance heating, flash vapor deposition, and crucible heating; (b) plasma deposition methods; (c) various sputtering methods, such as diode sputtering, DC sputtering, DC magnetron sputtering, RF sputtering, magnetron sputtering, ion beam sputtering, and bias sputtering; and (d) various ion plating methods, such as a direct current (DC) method, an RF method, a multi-cathode method, an activation reaction method, an electric field deposition method, an RF ion plating method, and a reactive ion plating method.

Examples of the material constituting the gate insulating layer include inorganic insulating materials, such as silicon oxide-based materials, silicon nitride, and metal oxide high-dielectric-constant insulating films; and organic insulating materials, such as polymethyl methacrylate (PMMA), polyvinyl phenol (PVP), and polyvinyl alcohol (PVA). These materials may be used in combination. Examples of the silicon oxide-based materials include silicon oxide, silicon oxynitride (SiON), spin-on glass (SOG), and low- dielectric-constant materials (e.g., polyaryl ethers, cycloperfluoro carbon polymers, benzocyclobutene, cyclic fluorocarbon resins, polytetrafluoroethylene, fluoroaryl ethers, polyfluoroimide, amorphous carbon, and organic SOG).

The gate insulating layer may be formed by oxidizing or nitriding the surface of the gate electrode or by depositing an oxide film or a nitride film on the surface of the gate electrode. As the method for oxidizing the surface of the gate electrode, although depending on the material constituting the gate electrode, for example, an oxidation method using oxygen plasma or an anodic oxidation method may be mentioned. As the method for nitriding the surface of the gate electrode, although depending on the material constituting the gate electrode, for example, a nitriding method using nitrogen plasma may be mentioned. Furthermore, for example, when a gate electrode composed of Au is used, a gate insulating layer may be formed in a self-assembling manner on the surface of the gate electrode by coating the surface of the gate electrode with insulating molecules having functional groups capable of forming chemical bonds with the gate electrode, such as linear hydrocarbon molecules with one end being modified with a mercapto group, using a dipping method or the like. Furthermore, for example, when a gate insulating layer composed of silicon dioxide is used, a supplementary insulating layer may be formed in a self-assembling manner on the surface of the gate insulating layer by coating the surface of the gate electrode with insulating molecules having functional groups capable of forming chemical bonds with the gate electrode, such as linear hydrocarbon molecules with one end being modified with a silane group, using a dipping method or the like.

Examples of the method for forming the channel-forming region, or the channel- forming region and the channel-forming region extension include the various PVD methods described above; spin coating methods; various printing methods described above; various coating methods described above; dipping methods; casting methods; and spraying methods. As necessary, additives may be added.

When the transistor devices are applied to or used for display devices or various types of electronic apparatuses, monolithic integrated circuits in which many semiconductor devices are integrated on supports may be fabricated, or the individual semiconductor devices may be separated by cutting to produce discrete components. Furthermore, the semiconductor devices may be sealed with resins.

EXAMPLES

In order that the invention may be more clearly understood, particular embodiments of the invention are described in further detail below by reference to the following non-limiting experimental materials, methodologies and examples.

PREPARATION OF COMPOUNDS

Example 1 - Compound 1

Scheme 1 : Synthesis of Compound 1 2-(( 5-Bromothiophen-2-yl) me -dione

To a solution of 5-bromothiophene-2-carbaldehyde (2.60 g, 13.6 mmol) in 50 mL of dry ethanol under N ₂ was added 1 ,3-indandione (2.00 g, 13.7 mmol) followed by 3 drops of piperidine. The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. The resulting precipitate was filtered off and washed with ethanol to give the product as a pale green powder (3.28 g, 75.6%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 7.20 (d, J = 4.0 Hz, 1 H), 7.63 (d, J = 4.0 Hz, 1 H), 7.78 (m, 2H), 7.86 (s, 1 H), 7.96 (m, 2H). 2,2'-((5, 5'-(9, 9-Dioctyl-9H-fluorene-2, 7-diyl)bis(thiophene-5, 2- diyl))bis(methanylylidene))bis(1H-indene-1,3(2H)-dione) , Compound 1

To a solution of 2-((5-bromothiophen-2-yl)methylene)-1 /-/-indene-1 ,3(2/-/)-dione

(816 mg, 2.56 mmol) in 30 mL of degassed DME\H ₂ 0 (9\1) under N ₂ was added 2,2'- (9,9-dioctyl-9/-/-fluorene-2,7-diyl)bis(1 ,3,2-dioxaborinane) (664 mg, 1.19 mmol), potassium carbonate (430 mg, 3.11 mmol) and palladium(0)tetrakis(triphenylphosphine) (82 mg, 0.07 mmol). The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. 50 mL of saturated ammonium chloride solution was added and the organic layer was extracted with DCM (50 mL x 2). The combined organic extracts were washed with de-ionised water (50 mL), saturated brine (50 mL) and then passed through a DryDisk™. The solvent was removed under vacuum and the resultant dark red powder was recrystallised from DCM\acetone (10 mLM OOmL) to give the product as crystalline red plates (743 mg, 72.1 %). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.64 (m, 4H), 0.75 (t, J = 6.8 Hz, 6H), 1.06 (m, 20H), 2.08 (m, 4H), 7.55 (d, J = 4.0 Hz, 2H), 7.73 (d, J = 1.2 Hz, 2H), 7.78 (m, 8H), 7.99 (m, 8H). HRMS (El, 70eV) m/z 866.3467, [M] requires 866.3464. Example 2 - Compound 2

2,2'-((5, 5'-(9, 9-Dihexyl-9H-fluorene-2, 7-diyl)bis(thiophene-5, 2- diyl))bis(methanylylidene))bis(1H-indene-1,3(2H)-dione) , Compound 2

The product was synthesized in the same manner as above. 2-((5- Bromothiophen-2-yl)methylene)-1 /-/-indene-1 , 3(2/-/)-dione (816 mg, 2.56 mmol), 30 mL of degassed DME\H ₂ 0 (9\1) under N ₂ , 2,2'-(9,9-dihexyl-9H-fluorene-2,7-diyl)bis(1 ,3,2- dioxaborinane) (598 mg, 1.19 mmol), potassium carbonate (430 mg, 3.1 1 mmol) and palladium(0)tetrakis(triphenylphosphine) (82 mg, 0.07 mmol). The product precipitated from the reaction mixture upon cooling and was filtered off then washed with ethanol to give the product as a red powder (462 mg, 47.9%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.64 (m, 4H), 0.73 (t, J = 7.2 Hz, 6H), 1.07 (m, 12H), 2.09 (m, 4H), 7.55 (d, J = 4.0 Hz, 2H), 7.73 (d, J = 1.2 Hz, 2H), 7.78 (m, 8H), 7.99 (m, 8H). LRMS (El, 70eV) m/z 810.3 [M] requires 810.3.

Example 3 - Compound 3

2,2'-((5, 5'-(9, 9-Dibutyl-9H-fluorene-2, 7-diyl)bis(thiophene-5, 2- diyl))bis(methanylylidene))bis( 1H-indene-1,3(2H)-dione), Compound 3

The product was synthesized in the same manner as above. 2-((5- Bromothiophen-2-yl)methylene)-1 /-/-indene-1 ,3(2/-/)-dione (816 mg, 2.56 mmol), 30 mL of degassed DME\H ₂ 0 (9\1) under N ₂ , 2,2'-(9,9-dibutyl-9H-fluorene-2,7-diyl)bis(4,4,5,5- tetramethyl-1 ,3,2-dioxaborolane) (631 mg, 1.19 mmol), potassium carbonate (430 mg, 3.11 mmol) and palladium(0)tetrakis(triphenylphosphine) (82 mg, 0.07 mmol). The product precipitated from the reaction mixture upon cooling and was filtered off then washed with ethanol to give the product as a red powder (548 mg, 60.0%). ¹ H NMR (CDCIs, 400 MHz): δ 0.62 (m, 4H), 0.67 (t, J = 7.6 Hz, 6H), 1.11 (m, 4H), 2.10 (m, 4H), 7.55 (d, J = 4.0 Hz, 2H), 7.73 (d, J = 1.2 Hz, 2H), 7.78 (m, 8H), 7.99 (m, 8H). LRMS (El , 70eV) m/z 754.2 [M] requires 754.2

Example 4 - Compound 32

2,2'-((5, 5'-(Benzo[c][1, 2, 5]thiadiazole-4, 7-diyl)bis(thiophene-5, 2- diyl))bis(methanylylidene))bis(1H-indene-1,3(2H)-dione) , Compound 32

To a solution of 2-((5-bromothiophen-2-yl)methylene)-1 /-/-indene-1 ,3(2/-/)-dione (362 mg, 1.13 mmol) in 30 mL of degassed DME\H ₂ 0 (9\1) under N ₂ was added 4,7- bis(4,4,5,5-tetramethyl-1 ,3,2-dioxaborolan-2-yl)benzo[c][1 ,2,5]thiadiazole (200 mg, 0.515 mmol), potassium carbonate (178 mg, 1.29 mmol) and palladium(0)tetrakis(triphenylphosphine) (18.0 mg, 1.55 μηιοΙ). The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. The precipitate which formed was filtered off to give the crude product as an intractable black powder (315 mg, 99.5%). Sublimation in a tube furnace at 350°C gave a small amount of pure product as a dark green powder (10.0 mg) with the unsublimed material being recovered. A ¹ H NMR spectrum was not obtained due to the insolubility of the compound. HRMS (El, 70eV) m/z 612.0273, [M] requires 612.0272.

Example 5 - Compound 43

Scheme 2: Synthesis of Compound 43

(Z)-5-((5-Bromothiophen-2-yl)methylene)- 1-ethyl-4-methyl-2, 6-dioxo- 1, 2, 5, 6- tetrahydropyridine-3-carbonitrile

5-Bromothiophene-2-carbaldehyde (1.91 g 10 mmol) and 1 -ethyl- 1 ,2-dihydro- 6-hydroxy-4-methyl-2-oxo-3-pyridine-carbonitrile (1.78g 10 mml) were added together in methanol (25m L) and refluxed for two hours. No catalytic base is required. During this time the solution turned orange and a precipitate formed. The solution was cooled and the product was collected by vacuum filtration to give an orange-brown solid. This was washed twice with methanol before drying on a watch glass to give the product (3.02 g, 86%) ¹ H NMR (CDCI3, 400 MHz) δ 1.20 (t, J 7.0 Hz, 3Hs, Me), 2.61 (s, 3Hs Me) , 4.03 (d. J 7 Hz, 2Hs, CH ₂ ), 7.28 (d, J 4.2, 1 H, thiophene), 7.53 (d, J 4.2, 1 H, thiophene) , 7.84 (s, 1 H, =CH-).

(5Z,5 )-5,5'-((5,5'-(9,9-Dioctyl-9H-fluorene-2, 7-diyl)

diyl) ) bis(methanylylidene)) bis( 1-ethyl-4-methyl-2, 6-dioxo- 1,2,5, 6-tetrahydropyridine-3- carbonitrile), C

To a solution of (Z)-5-((5-bromothiophen-2-yl)methylene)-1-ethyl-4-methyl-2,6 - dioxo-1 ,2,5,6-tetrahydropyridine-3-carbonitrile (900 mg, 2.56 mmol) in 30 ml_ of degassed DME\H ₂ 0 (9\1) under N ₂ was added 2,2'-(9,9-dioctyl-9/-/-fluorene-2,7- diyl)bis(1 ,3,2-dioxaborinane) (664 mg, 1.19 mmol), potassium carbonate (430 mg, 3.1 1 mmol) and palladium(0)tetrakis(triphenylphosphine) (82 mg, 0.07 mmol). The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. 50 ml_ of saturated ammonium chloride solution was added and the organic layer was extracted with DCM (50 ml_ x 2). The combined organic extracts were washed with de- ionised water (50 ml_), saturated brine (50 ml_) and then passed through a DryDisk™. The solvent was removed under vacuum and the resultant dark red powder was suspended in ethanol. 1-Ethyl-4-methyl-2,6-dioxo-1 ,2,5,6-tetrahydropyridine-3- carbonitrile (212 mg, 1.19 mmol) was added and the mixture refluxed for 6 hours. The reaction was cooled to room temperature and the precipitate was filtered off to give the product as a dark purple powder (789 mg, 71.2%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.62 (m, 4H), 0.74 (t, J = 6.8 Hz, 6H), 1.05 (m, 20H), 1.28 (t, J = 7.2 Hz, 6H), 2.09 (m, 4H),2.65 (s, 6H), 4.1 1 (q, J = 7.2 Hz, 4H), 7.63 (d, J = 4.0 Hz, 2H), 7.80 (m, 8H), 7.94 (s, 2H). LRMS (El, 70eV) m/z 929.8 [M] requires 930.4

Scheme 3: Synthesis of Compound 46

5-(( 5-Bromothiophen-2-yl) methylene) - 1, 3-di methyl pynmidine-2, 4, 6( 1 H, 3H, 5H) -trione

To a solution of 5-bromothiophene-2-carbaldehyde (955 mg, 5.00 mmol) in 50 mL of dry ethanol under N ₂ was added 1 ,3-dimethylbarbituric acid (781 mg, 5.00 mmol) followed by 3 drops of piperidine. The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. The resulting precipitate was filtered off and washed with ethanol to give the product as a pale green powder (1.30 g, 79.2%). ¹ H NMR (CDCIs, 400 MHz): δ 3.39 (s, 3H), 3.40 (s, 4H), 7.26 (d, J = 4.0 Hz, 1 H), 7.59 (d, J = 4.0 Hz, 1 H), 8.56 (s, 1 H).

5, 5'-((5, 5'-(9, 9-Dioctyl-9H-fluorene-2, 7-diyl)bis(thiophene-5, 2- diyl) ) bis(methanylylidene)) bis( 1, 3-di methyl yrimidine-2, 4, 6( 1H, 3H, 5H)-trione),

Compound 46

To a solution of 5-((5-bromothiophen-2-yl)methylene)-1 ,3-dimethylpyrimidine-

2,4,6(1 H,3H,5H)-trione (850 mg, 2.56 mmol) in 30 ml_ of degassed DME\H ₂ 0 (9\1) under N ₂ was added 2,2'-(9,9-dioctyl-9/-/-fluorene-2,7-diyl)bis(1 ,3,2-dioxaborinane) (664 mg, 1.19 mmol), potassium carbonate (430 mg, 3.11 mmol) and

palladium(0)tetrakis(triphenylphosphine) (82 mg, 0.07 mmol). The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. 50 ml_ of saturated ammonium chloride solution was added and the organic layer was extracted with DCM (50 ml_ x 2). The combined organic extracts were washed with de-ionised water (50 ml_), saturated brine (50 ml_) and then passed through a DryDisk™. The solvent was removed under vacuum and the resultant dark red powder recrystallized from acetonitrile\cyclohexane (10 ml_\100 ml_). This gave a hydrolysis product, 5-(7-(5- ((1 ,3-dimethyl-2,4,6-trioxotetrahydropyrimidin-5(2/-/)-ylidene) methyl)thiophen-2-yl)-9,9- dioctyl-9/-/-fluoren-2-yl)thiophene-2-carbaldehyde which was refluxed in ethanol with 1 ,3-Dimethylbarbituric acid (55.0 mg, 0.352 mmol) for 4 hours. The reaction was cooled to room temperature and the precipitate was filtered off to give the product as a dark purple powder (190 mg, 18.0%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.60 (m, 4H), 0.75 (t, J = 7.2 Hz, 6H), 1.05 (m, 20H), 2.07 (m, 4H), 3.42 (s, 3H), 3.46 (s, 3H), 7.60 (d, J = 4.0 Hz, 2H), 7.78 (m, 6H), 7.88 (d, J = 4.0 Hz, 2H), 8.68 (s, 2H). LRMS (El, 70eV) m/z 886.3 [M] requires 886.4.

Scheme 4: Synthesis of Compound 7 2-((5-Bromofuran-2-yl) methylene - 1 H-indene-1 ,3(2H)-dione

To a solution of 5-bromo-2-furaldehyde (1.94 g, 10.0 mmol) in 50 ml_ of dry ethanol under N ₂ was added 1 ,3-Dimethylbarbituric acid (1.75 g, 10.0 mmol) followed by 3 drops of piperidine. The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. The resulting precipitate was filtered off and washed with ethanol to give the product as a brown powder (1.89 g, 62.4%). ¹ H NMR (CDCIs, 400 MHz): δ 6.64 (d, J = 4.0 Hz, 1 H), 7.65(s, 1 H), 7.77 (m, 2H), 7.94 (m, 2H), 8.53 (d, J = 4.0 Hz, 1 H). 2,2'-((5, 5'-(9, 9-Dioctyl-9H-fluorene-2, 7-diyl)bis(furan-5, 2- diyl))bis(methanylylidene))bis( 1H-indene-1,3(2H)-dione), Compound 7

To a solution of 2-((5-bromofuran-2-yl)methylene)-1 /-/-indene-1 ,3(2/-/)-dione (776 mg, 2.56 mmol) in 30 mL of degassed DME\H ₂ 0 (9\1) under N ₂ was added 2,2'-(9,9- dioctyl-9/-/-fluorene-2,7-diyl)bis(1 ,3,2-dioxaborinane) (664 mg, 1.19 mmol), potassium carbonate (430 mg, 3.1 1 mmol) and palladium(0)tetrakis(triphenylphosphine) (82 mg, 0.07 mmol). The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. 50 mL of saturated ammonium chloride solution was added and the organic layer was extracted with DCM (50 mL x 2). The combined organic extracts were washed with de-ionised water (50 mL), saturated brine (50 mL) and then passed through a DryDisk™. The solvent was removed under vacuum and the resultant dark red powder was recrystallized from chloroform\acetone (10 mLM OOmL) to give the product as crystalline red needles (411 mg, 41.3%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.65 (m, 4H), 0.74 (t, J = 6.8 Hz, 6H), 1.05 (m, 20H), 2.10 (m, 4H), 7.09 (d, J = 3.2 Hz, 2H), 7.81 (m, 12H), 7.96 (m, 4H), 8.73 (s, 2H). LRMS (El, 70eV) m/z 834.4 [M] requires 834.4

Examples 8 & 9 - Compounds 29 & 47

Scheme 5: Synthesis of Compound 29

[2,2'-Bithiophene]-5, 5'-dicarba

To a solution of 2,2'-bithiophene (831 mg, 5.00 mmol) in 30ml_ of THF at -20°C under nitrogen was added, dropwise, 1.6M butyllithium (9.40 ml_, 15.0 mmol). The solution was stirred at for 30 minutes -20°C then at room temperature for another 30 minutes. The reaction was chilled to -20°C and DMF (1.6 ml_, 20.0 mmol) was added followed by stirring at room temperature for 16 hours. The reaction was quenched with H ₂ 0, the precipitate was filtered off and washed with H ₂ 0 and methanol to give the product as a yellow powder (990 mg, 89.1 %). ¹ H NMR (CDCI ₃ , 400 MHz): δ 7.40 (d, J = 4.0 Hz, 2H), 7.70 (d, J = 4.0 Hz, 2H), 9.90 (s, 2H).

2,2'-([2,2'-Bithiophene]-5, 5'-diylbis(methanylylidene))bis(1H-indene- 1, 3(2H)-dione), Compound 29

To a solution of [2,2'-bithiophene]-5,5'-dicarbaldehyde (333 mg, 1.50 mmol) in

50 ml_ of dry tert-butanol under N ₂ was added 1 ,3-indandione (680 mg, 3.50 mmol) followed by 3 drops of piperidine. The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. The resulting precipitate was filtered off, washed with ethanol and dried under high vacuum. The resulting powder was sublimed in a tube furnace at 320°C to give the product as blue-grey micro-crystals (422 mg, 58.8%). A ¹ H NMR spectrum was not obtained due to the insolubility of the compound. HRMS (El, 70eV) m/z 478.0315, [M] requires 478.0334.

5, 5'-([2,2'-Bithiophene]-5, 5'-diylbis(methanylylidene))bis( 1, 3-dimethylpyrimidine- 2,4, 6(1 H, 3H, 5H)-trione), Compound 47

To a solution of [2,2'-bithiophene]-5,5'-dicarbaldehyde (222 mg, 1.00 mmol) in 50 ml_ of dry tert-butanol under N ₂ was added 1 ,3- dimethylbarbituric acid (345 mg, 2.20 mmol) followed by 3 drops of piperidine. The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. The resulting precipitate was filtered off, washed with ethanol and dried under high vacuum. The resulting powder was sublimed in a tube furnace at 320°C to give the product as dark purple crystals (243 mg, 48.8%). A ¹ H NMR spectrum was not obtained due to the insolubility of the 5 compound. HRMS (El, 70eV) m/z 498.0660, [M] requires 498.0668.

Examples 10 & 11 - Compounds 27 & 48

Scheme 6: Synthesis of Compound 27

l o Thieno[3, 2-b]thiophene-2, 5-

To a solution of thieno[3,2-£>]thiophene (1.00 g, 7.13 mmol) in 30ml_ of THF at - 20°C under nitrogen was added, dropwise, 1.6M butyllithium (13.4 ml_, 21.4 mmol). The solution was stirred at for 30 minutes -20°C then at room temperature for another 15 30 minutes. The reaction was chilled to -20°C and DMF (2.30 ml_,28.5 mmol) was added followed by stirring at room temperature for 16 hours. The reaction was quenched with H ₂ 0, the precipitate was filtered off and washed with H ₂ 0 and methanol to give the product as a yellow powder (966 mg, 69.0%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 7.99 (s, 2H), 10.03 (s, 2H). 2,2'-(Thieno[3,2-b]thiophene-2,5-diylbis(methanylyliden

dione), Compound 27

To a solution of thieno[3,2-£>]thiophene-2,5-dicarbaldehyde (295 mg, 1.50 mmol) in 50 mL of dry tert-butanol under N ₂ was added 1 ,3-indandione (680 mg, 3.50 mmol) followed by 3 drops of piperidine. The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. The resulting precipitate was filtered off, washed with ethanol and dried under high vacuum. The resulting powder was sublimed in a tube furnace at 320°C to give the product as blue-grey micro-crystals (448 mg, 66.1 %). A ¹ H NMR spectrum was not obtained due to the insolubility of the compound. HRMS (El, 70eV) m/z 452.0165, [M] requires 452.0177.

5,5'-(Thieno[3,2-b]thiophene-2,5-diylbis(methanylylidene) )bis(1,3-dim

2, 4, 6(1 H, 3H, 5H)-trione), Compound 48

To a solution of thieno[3,2-b]thiophene-2,5-dicarbaldehyde (295 mg, 1.50 mmol) in 50 mL of dry tert-butanol under N ₂ was added 1 ,3- dimethylbarbituric acid (547 mg, 3.50 mmol) followed by 3 drops of piperidine. The solution was refluxed with stirring for 4 hours then allowed to cool to room temperature. The resulting precipitate was filtered off, washed with ethanol and dried under high vacuum. The resulting powder was sublimed in a tube furnace at 320°C to give the product as dark red micro-crystals (282 mg, 39.8%). A ¹ H NMR spectrum was not obtained due to the insolubility of the compound. HRMS (El, 70eV) m/z 472.0505, [M] requires 472.051 1. Exam le 12 -Compound 58

Scheme 7: Synthesis of Compound 58

Benzo[b]thiophen-3(2H)-one 1, 1-dioxide

Ethyl benzoylacetate (5.00 g, 26.0 mmol) was added dropwise to 20% S0 ₃ in H ₂ S0 ₄ (30 mL) at 0°C over 10 mins and stirred for 30 mins at 0°C. H ₂ 0 (50 mL) was added slowly and carefully, keeping the reaction temperature below 5°C. The white precipitate was filtered off and washed with H ₂ 0 to give the intermediate ethyl 3- hydroxybenzo[b]thiophene-2-carboxylate 1 , 1 -dioxide. This was dissolved into ethanol containing 20% H ₂ S0 ₄ (100 mL) and refluxed for 8 hrs. Once cooled, H ₂ 0 (100 mL) was added and the reaction chilled to 0°C. The product crystallised out as fine white needles, was filtered off and washed with ice cold ethanol (2.74 g, 57.8%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 4.13 (s, 2H), 7.87 (dt, 1 H, J = 1.6 Hz, 6.8 Hz), 7.99 (dt, 1 H, J = 1.2 Hz, 7.6 Hz), 8.05 (m, 2H).

A mixture of 9,9-dioctyl-2,7-diboronic acid bis(1 ,3-propandiol) ester (5.00 g, 8.95 mmol), freshly distilled 2-bromo-5-formylthiophene (5.12 g, 26.8 mmol), and tetrakis(triphenylphosphine)palladium (1.00 g, 0.87 mmol) in DME (80 ml_) and 1 M Na ₂ C0 ₃ (60 ml_) was refluxed under N ₂ for 24 hrs. The reaction was cooled and the DME removed under vacuum. The residue was treated with DCM (150 ml_) and water (75 ml_) and the organic layer collected. The organic layer was then washed with 1 M HCI (75 ml_), water (120 ml_) and dried (Drydisk™). The solvent was removed under reduced pressure to afford a crude yellow/orange solid. This material was dissolved in a minimum amount of DCM and adsorbed to silica gel. The material was filtered through a short silica column eluting with increasing portions of ethyl acetate in petroleum ether. The appropriate fractions were collected, combined and concentrated under vacuum to afford a yellowish solid. This crude material was recrystallised from DCM/diethyl ether/petroleum ether to afford the product as fluffy yellow needles (4.08 g, 75%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.65 (m, 4H), 0.76 (t, 6H, J = 7.2 Hz), 1.10 (m, 20H), 2.01 (m, 4H), 7.47 (d, 2H, J = 4.0 Hz), 7.62 (d, 2H, J = 1.2 Hz), 7.68 (dd, 2H, J = 1.6 Hz, 8.0 Hz), 7.75 (m, 4H), 9.90 (s, 2H).

(2E,2'E)-2,2'-((5,5'-(9,9-Dioctyl-9H-fluorene-2,7-diyl)bis(t hiophene-5,2- diyl))bis(methan , Compound 58

5,5'-(9,9-Dioctyl-9/-/-fluorene-2,7-diyl)bis(thiophene-2-car baldehyde) (500 mg,

0.818 mmol) and benzo[b]thiophen-3(2/-/)-one 1 ,1-dioxide (447 mg, 2.46 mmol) were dissolved into tert-butanol (50 ml_). Sodium tert-butoxide (10.0 mg, 0.104 mmol) was added and the reaction refluxed under N ₂ for 6 hours. After cooling to room

temperature ethanol (50 ml_) was added and the resulting red precipitate filtered off to give the product as a papery red powder (368 mg, 47.9%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.67 (m, 4H), 0.81 (t, 6H, J = 6.8 Hz), 1.17 (m, 20H), 2.12 (m, 4H), 7.63 (d, 2H, J = 4.0 Hz), 7.71 (s, 2H), 7.81 (m, 4H), 7.87 (dt, 2H, J = 1.2 Hz, 7.6 Hz), 7.96 (dt, 2H, J = 1.2 Hz, 7.6 Hz), 8.12 (m, 8H). MOLDI-TOF m/z 938 [M] requires 938.

Example 13 - Compound 65

Scheme 8: Synthesis of Compound 65

2, 7-Dibromo-9, 9-bis(2-ethylh

2,7-Dibromofluorene (2.25 g, 6.94 mmol) was dissolved into THF (50 ml_) and chilled to 0°C. Sodium tert-butoxide (1.70 g, 17.7 mmol) was added at 0°C under N ₂ and the reaction stirred at 0°C for 15 mins. 1-Bromo-2-ethylhexane (5.00 ml_, 28.1 mmol) was added dropwise at 0°C, the reaction was allowed to warm to room temperature and was stirred for 3 hrs. Saturated NH ₄ CI solution (50 ml_) was added and the product extracted into DCM (2 x 25 ml_). The organic phases were combined and washed with H ₂ 0 (50 ml_) and brine solution (50 ml_) then dried over MgS0 ₄ . The MgS0 ₄ was filtered off and the solvent removed under vacuum. The crude product was dissolved into petroleum ether (50 ml_) and filtered through a silica plug eluting with more petroleum ether. The solvent was removed under vacuum to give the product as a clear oil (3.38 g, 88.8%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.49 (q, 2H, J = 5.6 Hz), 0.57 (t, 3H, J = 7.2 Hz), 0.58 (t, 3H, J = 7.2 Hz), 0.83 (m, 24H), 1.95 (m, 2H), 7.47 (dd, 2H, J = 1.6 Hz, 8.0 Hz), 7.52 (m, 4H).

2,2'-(9, 9-bis(2-ethylhexyl)-9H-fluorene-2, 7-diyl)bis(4, 4, 5, 5-tetramethyl- 1, 3, 2- dioxab

dissolved into THF (50 ml_) under N ₂ and chilled to -78°C. 1.6M Butyllithium (1 1.6 ml_, 18.5 mmol) was added dropwise and the reaction was stirred at -78°C for 30 mins. 2- lsopropoxy-4,4,5,5-tetramethyl-1 ,3,2-dioxaborolane (7.60 ml_, 37.0 mmol) was added and the reaction allowed to warm to room temperature then stirred for 16 hrs. H ₂ 0 (50 ml_) was added and the THF was removed under vacuum. The residue was extracted with DCM (2 x 50 ml_) and the organic fractions combined. These were washed with H ₂ 0 (100 ml_), brine solution (50 ml_) and dried (Drydisk™). The solvent was removed under vacuum and the crude oil was purified by vacuum chromatography on silica gel eluting with DCM/petroleum ether, 30/70 ratio, to give the product as a clear oil (2.41 g, 60.9%). ¹ H NMR (CDCIs, 400 MHz): δ 0.51 (m, 8H), 0.80 (m, 22H), 1.39 (s, 24H), 2.03 (d, 4H, J = 5.2 Hz), 7.72 (d, 2H, J= 7.6 Hz), 7.80 (d, 2H, J= 7.6 Hz), 7.85 (t, 2H, J Hz). '-(9, 9-bis(2-ethylhexyl)-9H-fluorene-2, 7-diyl)bis(thiophene-2-carbaldehyde)

This was synthesised in a similar manner to 5,5'-(9,9-dioctyl-9/-/-fluorene-2,7- diyl)bis(thiophene-2-carbaldehyde). 2,2'-(9,9-bis(2-ethylhexyl)-9/-/-fluorene-2,7- diyl)bis(4,4,5,5-tetramethyl-1 ,3,2-dioxaborolane) (1.13 g, 1.75 mmol), freshly distilled 2- bromo-5-formylthiophene (1.00 g, 5.25 mmol), and

tetrakis(triphenylphosphine)palladium (200 mg, 0.173 mmol) in DME (17 mL) and 1 M Na ₂ C0 ₃ (13 mL). The product was obtained as a yellow powder (960 mg, 89.8%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.58 (m, 14H), 0.82 (m, 16H), 2.09 (m, 4H), 7.48 (d, 2H, J = 4.0 Hz), 7.71 (m, 4H), 7.79 (m, 4H), 9.94 (s, 2H).

2,2'-((5, 5'-(9, 9-bis(2-ethylhexyl)-9H-fluorene-2, 7-diyl)bis(thiophene-5, 2- diyl))bis(methanylylidene))bis( 1H-indene-1,3(2H)-dione), Compound 65

This was synthesised in a similar manner to (2E,2'E)-2,2'-((5,5'-(9,9-dioctyl-9/-/- fluorene-2,7-diyl)bis(thiophene-5,2-diyl))bis(methanylyliden e))-bis(benzo[ 5]thiophen- 3(2/-/)-one 1 , 1-dioxide). 5,5'-(9,9-bis(2-ethylhexyl)-9/-/-fluorene-2,7-diyl)bis(thiop hene-2- carbaldehyde) (400 mg, 0.655 mmol), 1 ,3-indandione (280 mg, 1.92 mmol), sodium tert-butoxide (8.00 mg, 0.083 mmol) in tert-butanol (50 mL). The filtered precipitate was recrystallised from DCM/acetone (5 ml_/75 mL) to give the product as red micro- crystals (259 mg, 45.6%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.60 (m, 14H), 0.89 (m, 16H), 2.16 (m, 4H), 7.57 (d, 2H, J = 4.4 Hz), 7.83 (m, 10H), 8.02 (m, 8H). LRMS (El, 70eV) m/z 866.4 [M] requires 866.3. Example 14 - Compound 18

Scheme 9: Synthesis of Compound 18

5, 5'-(9-(Heptadecan-8-yl)-9H-carbazole-2, 7-diyl)bis(thiophene-2-carbaldehyde)

This was synthesised in a similar manner to 5,5'-(9,9-dioctyl-9/-/-fluorene-2,7- diyl)bis(thiophene-2-carbaldehyde); 9-(heptadecan-8-yl)-2,7-bis(4,4,5,5-tetramethyl- 1 ,3,2-dioxaborolan-2-yl)-9/-/-carbazole (1.00 g, 1.52 mmol), freshly distilled 2-bromo-5- formylthiophene (872 mg, 4.56 mmol), and tetrakis(triphenylphosphine)palladium (88.0 mg, 0.076 mmol) in DME (17 mL) and 1 M Na ₂ C0 ₃ (13 mL). The product was obtained as a yellow oil (925 mg, 97.2%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.81 (t, (6H, J = 6.8 Hz), 1.18 (m, 24H), 2.02 (m, 2H), 2.05 (m, 2H), 4.64 (sept, 1 H, J = 4.8 Hz), 7.54 (d, 2H, J = 3.6 Hz), 7.60 (d, 2H, J = 5.2 Hz), 7.71 (s, 1 H), 7.82 (d, 2H, J = 4 Hz), 7.90 (s, 1 H), 8.16 (t, 2H, J = 10.4 Hz), 9.95 (s, 2H).

2,2'-((5, 5'-(9-(Heptadecan-8-yl)-9H-carbazole-2, 7-diyl)bis(thiophene-5, 2- diyl) ) bis(methanylylidene)) bis( 1H-indene- 1, 3(2H)-dione)

This was synthesised in a similar manner to (2E,2'E)-2,2'-((5,5'-(9,9-dioctyl-9/-/- fluorene-2,7-diyl)bis(thiophene-5,2-diyl))bis(methanylyliden e))-bis(benzo[ 5]thiophen- 3(2/-/)-one 1 , 1-dioxide); 5,5'-(9-(Heptadecan-8-yl)-9/-/-carbazole-2,7-diyl)bis(thioph ene- 2-carbaldehyde) (586 mg, 0.980 mmol), 1 ,3-indandione (575 mg, 3.94 mmol), sodium tert-butoxide (19.0 mg, 0.197 mmol) in tert-butanol (50 mL). The filtered precipitate was recrystallised from DCM/acetone (5 ml_/75 mL) to give the product as olive-bronze flakes (255 mg, 30.9%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.75 (t, 6H, J = 6.4 Hz), 1.17 (m, 24H), 2.03 (m, 2H), 2.36 (m, 2H), 4.68 (sept, 1 H J = 4.8 Hz), 7.57 (m, 2H), 7.67 (m, 2H), 7.78 (m, 5H), 7.99 (m, 8H), 8.1 1 (m, 3H). LRMS (El, 70eV) m/z 881.4 [M] requires 881.4.

Example 15 - Compound 4

2,2·-((2Ζ,2·Ζ)-((5, 5'-(9, 9-dioctyl-9H-fluorene-2, 7-diyl)bis(thiophene-5, 2- diyl))bis(methanylylidene))bis(3-oxo-2,3-dihydro-1H-indene-2 , 1- diylidene)) dimalononitrile

This was synthesised in a similar manner to (2E,2'£)-2,2'-((5,5'-(9,9-dioctyl-9/-/- fluorene-2,7-diyl)bis(thiophene-5,2-diyl))bis(methanylyliden e))-bis(benzo[ 5]thiophen- 3(2/-/)-one 1 , 1-dioxide); 5,5'-(9,9-Dioctyl-9/-/-fluorene-2,7-diyl)bis(thiophene-2- carbaldehyde) (412 mg, 0.675 mmol), 2-(3-oxo-2,3-dihydro-1 /-/-inden-1- ylidene)malononitrile (393 mg, 2.02 mmol), sodium tert-butoxide (13.0 mg, 0.135 mmol) in tert-butanol (50 mL). The filtered precipitate was recrystallized from

DCM/acetone (5 mL/75 mL) to give the product as very dark green micro-crystals (259 mg, 45.6%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.68 (m, 4H), 0.79 (t, 6H, J = 7.2 Hz), 1.12 (m, 20H), 2.14 (m, 4H), 7.65 (d, 2H, J = 4 Hz), 7.82 (m, 8H), 7.90 (dd, 2H, J = 1.6 Hz, 8.0 Hz), 7.95 (d, 2H, J = 4.4 Hz), 8.01 (m, 2H), 8.76 (dd, 2H, J = 1.2 Hz, 6.0 Hz), 8.95 (s, 2H). MOLDI-TOF m/z 962 [M] requires 962. Example 16 - Compound 28

5, 5'-(thieno[3, 2-b]thiophene-2, 5-diylbis(methanylylidene))bis( 1, 3-diethyl-2- thioxodihydro-pyrimidine-4, 6( 1H, 5H)-dione)

To a solution of thieno[3,2-b]thiophene-2,5-dicarbaldehyde (408 mg, 2.08 mmol) in 80 mL of dry tert-butanol under N ₂ was added 1 ,3- diethyl-2-thiobarbituric acid (1.25 g, 6.24 mmol). The solution was refluxed with stirring for 6 hours then allowed to cool to room temperature. The resulting precipitate was filtered off, washed with ethanol and dried under high vacuum. The resulting powder was sublimed in a tube furnace at 320°C to give the product as blue micro-crystals ( mg, %). ¹ H NMR(CDCI ₃ , 400 MHz): δ 1.31 (t, J = 7.2 Hz, 6H), 1.34 (t, J = 7.2 Hz, 6H), 4.58 (m, 8H), 8.07 (s, 2H), 8.74 (s, 2H).

Example 17 - Compound 35

5, 5'-([2,2'-bithiophene]-5, 5'-diylbis(methanylylidene))bis(1, 3-diethyl-2- thioxodihydropyrimidin -4, 6( 1H, 5H)-dione))

To a solution of [2,2'-bithiophene]-5,5'-dicarbaldehyde (556 mg, 2.50 mmol) in

80 mL of dry tert-butanol under N ₂ was added 1 ,3-diethyl-2-thiobarbituric acid (1.50 g, 7.50 mmol). The solution was refluxed with stirring for 6 hours then allowed to cool to room temperature. The resulting precipitate was filtered off, washed with ethanol and dried under high vacuum. The resulting powder was sublimed in a tube furnace at 320°C to give the product as dark blue micro- crystals (600 mg, 41.0 %). ¹ H

NMR(CDCI ₃ , 400 MHz): δ 1.30 (t, J = 7.2 Hz, 6H), 1.35 (t, J = 7.2 Hz, 6H), 4.58 (m, 8H), 7.67 (d, J = 4.0 Hz, 2H), 7.83 (d, J = 4.0 Hz, 2H), 8.64 (s, 2H). HRMS (El, 70eV) m/z 586.0813, [M] requires 586.0837. Example 18 - Compound 31

2,2'-((5, 5'-(5, 5-dioctyl-5H-dibenzo[b, d]silole-3, 7-diyl)bis(thiophene-5, 2- diyl) ) bis(methanyl-ylidene)) bis( 1H-indene- 1, 3(2H)-dione)

Scheme 10: Synthesis of Compound 31

5,5'-(5,5-dioctyl-5H-dibenzo[b,d]silole-3 -diyl)bis(thiophene-2-carbaldehy

This aldehyde was synthesised in a similar manner to 5,5'-(9,9-dioctyl-9/-/- fluorene-2,7-diyl)bis(thiophene-2-carbaldehyde). 5,5-dioctyl-3,7-bis(4,4,5,5-tetramethyl- 1 ,3,2-dioxaborolan-2-yl)-5/-/-dibenzo[ 5,c]silole (485 mg, 0.736 mmol), freshly distilled 2-bromo-5-formylthiophene (422 mg, 2.21 mmol), and tetrakis(triphenylphosphine)palladium (42.0 mg, 0.036 mmol) in DME (12 mL) and 1 M Na ₂ C0 ₃ (8 mL). The product was obtained as a yellow powder (436 mg, 94.4%). ¹ H NMR (CDCIs, 400 MHz): δ 0.80 (t, J = 6.8 Hz, 6H), 1.01 (m, 4H), 1.11 - 1.41 (m, 24H), 7.45 (d, J = 4.0 Hz, 2H), 7.75 (d, J = 4.0 Hz, 2H), 7.76 (dd, J = 2.0 Hz, 8.0 Hz, 2H), 7.86 (d, J = 8.0 Hz, 2H), 7.89 (d, J = 2.0 Hz, 2H), 9.89 (s, 2H).

2,2'-((5, 5'-(5, 5-dioctyl-5H-dibenzo[b, d]silole-3, 7-diyl)bis(thiophene-5, 2- diyl) ) bis(methan -ylidene)) bis( 1H-indene- 1, 3(2H)-dione)

5,5'-(5,5-Dioctyl-5/-/-dibenzo[ 5,c]silole-3,7-diyl)bis(thiophene-2-carbaldehyde) (435 mg, 0.694 mmol), 1 ,3-indandione (304 mg,2.08 mmol) and piperidine (2 drops)was dissolved into tert-butanol (30 mL) then refluxed under nitrogen for 6 hours. The cooled reaction was quenched with H ₂ 0 (150 mL) and the product extracted with DCM (3 x 50 mL). The organic fractions were combined, washed with H ₂ 0 (2 x 100 mL) and saturated brine solution (50 mL) then passed through a DryDisk™. The solvent was removed under vacuum and the residue was recrystallised from

DCM/acetone (5 mL/100 mL) to give the product as purple micro-crystals (417 mg, 68.0%). ¹ H NMR (CDCI ₃ , 400 MHz): δ 0.79 (t, J = 6.8 Hz, 6H), 1.06 (m, 4H), 1.12 - 1.40 (m, 24H), 7.53 (d, J = 4.0 Hz), 7.79 (m, 4H), 7.89 (m, 4H), 7.98 (m, 8H), 8.02 (m, 2H). LRMS (El, 70eV) m/z 882.1 , [M] requires 882.3

Example 19 - Compound 76

5,5'-([2,2'-bithiophene]-5,5'-diylbis(methanylylidene))bis(1 ,3-diethylpyrim

2,4, 6(1 H,3H,5H)-trione

To a solution of [2,2'-bithiophene]-5,5'-dicarbaldehyde (333 mg, 1.50 mmol) in 75 mL of dry tert-butanol under N ₂ was added 1 ,3-diethyl-barbituric acid (645 mg, 3.50 mmol) and 3 drops of piperidine. The solution was refluxed with stirring for 6 hours then allowed to cool to room temperature. The resulting precipitate was filtered off, washed with ethanol and dried under high vacuum. The resulting powder was sublimed in a tube furnace at 320°C to give the product as blue-purple micro-crystals (564 mg, 67.8 %). A ¹ H NMR spectrum was not obtained due to the insolubility of the compound. HRMS (El, 70eV) m/z 554.1289, [M] requires 554.1294. Elemental analysis requires: C 56.30%, H 4.72%, N 10.10%, S 1 1.56% Found: C 56.38%, H 4.74%, N 10.12%, S 11.47%.

PREPARATION OF PHOTOACTIVE OPTOELECTRONIC DEVICE

Bi layer Solar Cell

A bilayer organic solar cell (1) according to one embodiment of the invention is illustrated in Figure 1. The bilayer organic solar cell comprises a transparent layer of indium tin oxide as the anode (2) supported on a transparent thin film support (3), and a cathode (4) in the form of a metal cathode, opposite. Between the anode and cathode are layers of an electron donor material (or p-conductor) (5), for example

P3HT, and an electron acceptor material (6) (or n-conductor), for example a compound of Formula 1. The device may contain multiple layers, and the term "bilayer" should be interpreted as encompassing 2 or more layered devices. The device may be in the form of a single cell, or multiple cells connected in parallel and/or series. The device typically further comprises positive and negative terminals (not illustrated) for connection to an energy storage device or other electrical component(s) or circuit(s).

Bulk Heterojunction Solar Cell

A bulk heterojunction organic solar cell (7) according to one embodiment of the invention is illustrated in Figure 2. In this figure, elements that are common to the bilayer solar cell (1) of Figure 2 are referred to using the same numerals. The bulk heterojunction organic solar cell (7) comprises a transparent layer of indium tin oxide as the anode (2) supported on a transparent thin film support (3), and a cathode (4) in the form of a metal cathode, opposite. Between the anode and cathode is an active material comprising a blend of electron acceptor material (6) (or n-conductor), for example a compound of Formula 1 , and an electron donor (or p-conductor) material (5), for example P3HT. The concentration of each component (5) and (6) gradually increases when approaching to the corresponding electrode. The device may be in the form of a single cell, or multiple cells connected in parallel and/or series. The device typically further comprises positive and negative terminals (not illustrated) for connection to an energy storage device or other electrical component(s) or circuit(s).

Apparatus

Indium tin oxide (ITO) coated glass with a sheet resistance of 15 Ω/square was purchased from Kintek. Polyethylenedioxythiophene/polystyrenesulfonate

("PEDOT/PSS") (Baytron P Al 4083) was purchased from HC Starck. PCBM and C60 were purchased from Nano-C. Calcium pellets and 2,9-dimethyl-4,7-diphenyl-1 , 10- phenanthroline (BCP) were purchased from Aldrich. Aluminium pellets (99.999%) were purchased from KJ Lesker.

UV-ozone cleaning of ITO substrates was performed using a Novascan PDS- UVT, UV/ozone cleaner with the platform set to maximum height, the intensity of the lamp is greater than 36 mW/cm ² at a distance of 100 cm. At ambient conditions the ozone output of the UV cleaner is greater than 50 ppm.

Aqueous solutions of PEDOT/PSS were deposited in air using a Laurell WS-

400B-6NPP Lite single wafer spin processor. Organic blends were deposited inside a glovebox using an SCS-23NPP-Lite Spincoater. Film thicknesses were determined using a Dektak 6M Profilometer. It was further confirmed by atomic force microscopy. Vacuum depositions were carried out using an Angstrom Engineering evaporator inside a glovebox. Samples were placed on a shadow mask in a tray with a source to substrate distance of approximately 0.5 m. The area defined by the shadow mask gave device areas of 0.1 cm ² . Deposition rates and film thicknesses were measured and controlled by Sigma-SQS-242 software using a calibrated quartz thickness monitor inside the vacuum chamber. C60 was evaporated from a boron nitride crucible positioned inside a Radak furnace. BCP was also evaporated from a boron nitride crucible positioned inside a Radak furnace. Ca was evaporated from separate open tungsten boat supplied by RD Mathis. Al (4 pellets) was evapoated from alumina coated graphite boat which was supplied by Momentive Performance Materials. Al and Ca were supplied by K. J. Lesker.

Methods

ITO coated glass was cleaned by standing in a stirred solution of 5% (v/v) Deconex 12PA detergent at 90 °C for 20 mins. The ITO was successively sonicated for 10 minutes each in distilled water, acetone and / ^' so-propanol. The substrates were then exposed to a UV-ozone clean (at room temperature) for 10 minutes. The PEDOT/PSS solution was filtered (0.2 μηι RC filter) and deposited by spin coating at 5000 rpm for 20 sec to give a 38 nm layer. The PEDOT/PSS layer was then annealed on a hotplate in the glovebox at 140 °C for 10 minutes. Where used, solutions of the organic blends were deposited onto the PEDOT/PSS layer by spin coating inside a glovebox (H ₂ 0 and 0 ₂ levels both < 1 ppm). A Laurell WS-650SZ6-NPP Lite spin coater was used.

Spinning conditions and film thicknesses were optimised for each blend. The devices were transferred (without exposure to air) to a vacuum evaporator in an adjacent glovebox. Where used, single layers of the organic materials were deposited sequentially by thermal evaporation at pressures below 2* 10 ^"6 mbar. Alternatively, organic layers were dissolved in a semitransparent glass vial inside the glove box with appropriate weight/volume in a solvent such as chlorobenezene and 1 ,2- dichlorobenezene. Well dissolved solutions were readily spin coated using a Laurell WS-650SZ-23NPP Lite single wafer spin processor. The spin parameters ranges from 2000-3000 RPM with an acceleration of 6000 RPM. The thin films were further thermally annealed at 120°C for 10 minutes. Where used, a layer of Ca was deposited by thermal evaporation at pressures below 2* 10 ^~7 mbar. For all devices a layer of Al was deposited by Angstrom Engineering evaporator at pressures below 2* 10 ^~7 mbar. Where noted, the devices were then annealed on a hotplate in the glovebox.

A small amount of silver paint (Silver Print II, GC electronics, Part no.: 22-023) was deposited onto the connection points of the electrodes. Completed devices were encapsulated with glass and a UV-cured epoxy (Lens Bond type J-91) by exposing to 254nm UV-light inside a glovebox (H ₂ 0 and 0 ₂ levels both < 1 ppm) for 10 minutes. Electrical connections were made using alligator clips.

The cells were tested with an Oriel solar simulator fitted with a 1000W Xe lamp filtered to give an output of 100mW/cm ² at AM 1.5. The lamp was calibrated using a standard, filtered Si cell from Peccell limited (The output of the lamp was adjusted to give a JSC of 0.605 mA). The estimated mismatch factor of the lamp is 0.95. Values were not corrected for this mismatch.

The measurements on the solar simulator gave the cell efficiency under AM 1.5 illumination.

Device Example 1

Compound 1 was used in a blend device as an electron acceptor material with P3HT as the electron donor material. Device structure: ITO / PEDOT:PSS (38 nm) / Compound 1 : P3HT (1 : 1.2) (1 10 nm) / Ca ( 20 nm) / AI (100nm).

A 1 cm ³ solution of Compound 1 (15 mg) in 0.5 ml of ortho-dichlorobenzene and P3HT (18 mg) in 0.5 ml of ortho-dichlorobenzene were separately prepared by stirring for 30 mins. The solutions were mixed, filtered (0.2 μηι RC filter) and spin coated at 3000 rpm for 60 second with an acceleration of 6000 rpm. Prior to the vacuum deposition of electrodes, the thin films were annealed at 120°C for 10 minutes. Vacuum deposition of the Ca (20 nm) and Al (100 nm) layers were done using an Agstrom evaporator in the glove box.

The l-V curve for the device is shown in Figure 3. The device parameters were

Voc = 830 mV, Isc = 4.8 mA/cm ² , FF =52.53 %, PCE = 2.04%.

Device Example 2

Compound 7 was used in a blend device as an electron acceptor material with P3HT as the electron donor material.

Device structure: ITO / PEDOT:PSS (38nm) / Compound 7 : P3HT (1.25: 1) / Ca (20 nm) / Al (100 nm). A 1 cm ³ solution of Compound 7 (15 mg) in 0.5 ml of ortho- dichlorobenzene and P3HT (12 mg) in 0.5 ml of ortho-dichlorobenzene were separately prepared by stirring for 30 mins. The solutions were mixed, filtered (0.2 μηι RC filter) and spin coated at 3000 rpm for 60 second with an acceleration of 6000 rpm. Prior to the vacuum deposition of electrodes, the thin films were annealed at 120°C for 10 minutes. Vacuum deposition of the Ca (20 nm) and Al (100 nm) layers were done using an Agstrom evaporator in the glove box. The l-V curve for the device is shown in Figure 4. The device parameters were V ₀ c = 730 mV, l _S c = 3.19 mA/cm ² , FF =

30.79%, PCE = 0.72%.

Device Example 3

Compound 46 was used in a blend device as an electron acceptor material with P3HT as the electron donor material.

Device structure: ITO / PEDOT:PSS (38 nm) / Compound 46 : P3HT (1.25: 1) /

Ca (20nm) / AI (100 nm).

A 1 cm ³ solution of Compound 46 (15 mg) in 0.5 ml of ortho-dichlorobenzene and P3HT (12 mg) in 0.5 ml of ortho-dichlorobenzene were separately prepared by stirring for 30 mins. The solutions were mixed, filtered (0.2 μηι RC filter) and spin coated at 3000 rpm for 60 second with an acceleration of 6000 rpm. Prior to the vacuum deposition of electrodes, the thin films were annealed at 120°C for 10 minutes. Vacuum deposition of the Ca (20 nm) and Al (100 nm) layers were done using an Agstrom evaporator in the glove box. The l-V curve for the device is shown in Figure 5. The device parameters were V _oc = 760 mV, \ _sc = 2.79 mA/cm ² , FF = 54.35%, PCE = 1.15%.

PREPARATION OF TRANSISTOR DEVICE

Apparatus

Figure 6 shows bottom gate/top contact transistor architecture with a surface treatment applied to the dielectric layer. Transistor substrates ("substrates") of thermally grown silicon dioxide ("Si02", "dielectric", "dielectric layer") of thickness 230nm on an n-doped (N ~ 3 χ 10 ¹⁷ cm ^"3 ) silicon ("n-Si") wafer ("Gate", "Gate electrode") were obtained from the Fraunhofer Institute. Solvents used for cleaning, acetone and / ^' so-propanol, were of the Empure grade and were used as purchased from Merck KGaA. Hexamethyldisilazane ("HMDS") was used as supplied by Sigma Aldrich and octadecyltrichlorosilane ("OTS") was used as supplied by Gelest Inc. Anhydrous cyclohexane was purchased from Sigma-Aldrich. Gold pieces (99.9999%) were purchased from Saffo. The organic materials were prepared as described.

A Binder vacuum oven connected to an Edwards RV3 vacuum pump was used to store substrates at elevated temperatures under vacuum following solvent cleaning. UV-ozone cleaning of transistor substrates was performed using a Novascan PDS- UVT, UV/ozone cleaner with the platform set to maximum height, the intensity of the lamp is greater than 36 mW/cm ² at a distance of 10 cm. At ambient conditions the ozone output of the UV cleaner is greater than 50 ppm. Where used, a Laurell WS- 650SZ6-NPP Lite spin coater was used for spincoating, which was carried out in air Vacuum depositions were carried out using an Angstrom Engineering evaporator opening into an M Braun glovebox, thermal evaporations being carried out at pressures below CCC with source to substrate distances of approximately 0.5m. Deposition rates and film thicknesses were measured and controlled by Sigma-SQS- 242 software using a calibrated quartz thickness monitor inside the vacuum chamber and confirmed by subsequent measurement using a Dektak 6M Profilometer and by atomic force microscopy on blank samples and on completed devices after electrical measurements had been taken. Organic compounds were evaporated from an

Alumina crucible positioned inside a Radak furnace. Evaporations of metals were carried out by evaporation of the chosen metal from an open tungsten boat supplied by RD Mathis.

Electrical testing of devices was carried out in an M Braun glovebox using Suss Microtech probes to make electrical connections between the electrodes of the device and the Agilent B1500A Semiconductor Device Analyser ("Analyser"). A contact pad to facilitate the making of the electrical connection from the Analyser to the Gate electrode of the device was made by drilling through the gate dielectric layer and into the Gate electrode using a Dremel drill and applying High Purity Silver Paint purchased from SPI-Paint to form the contact pad.

Methods

Transistor substrates were cleaned by rinsing briefly in acetone and then successively sonicating for 5 minutes each in acetone and then in / ^' so-propanol.

Substrates were then dried in a stream of Nitrogen gas before being placed under vacuum in a vacuum oven at 100°C overnight. Substrates were then removed from the vacuum oven, placed on the platform of the UV-ozone cleaner for two minutes and then given a UV-ozone treatment for 10 minutes with the platform set to maximum height, the intensity of the lamp is greater than 36 mW/cm ² at a distance of 10 cm. At ambient conditions the ozone output of the UV cleaner is greater than 50 ppm.

Subsequently surface treatments were applied to the dielectric layer. Where used, a hexamethyldisilazane (HMDS) treatment of the freshly cleaned dielectric layer surface was carried out by dropping neat HMDS onto the substrate so as to wet the surface, this was left for 1 minute and then the excess removed by spincoating (4000rpm for 40s with an acceleration of 2000rpm/s). Substrates were subsequently placed on a hotplate at a temperature of 1 15°C in air. Where used, an

octadecyltrichlorosilane (OTS) treatment of the freshly cleaned dielectric layer was applied by soaking freshly cleaned substrates in a 2mM solution of OTS in anhydrous cyclohexane for 16 hours in a dessicator under anhydrous conditions. Substrates were then rinsed briefly in neat anhydrous cyclohexane and then dried in a stream of nitrogen gas. Substrates were then transferred to a glovebox (H ₂ 0 and 0 ₂ levels both < 1 ppm) and maintained under an inert atmosphere throughout the rest of the fabrication process and until after electrical testing of the completed devices.

For deposition of the organic compounds, samples were placed into a substrate holder and maintained in position by retaining screws with a source to substrate distance of approximately 0.5 m when loaded into an Angstrom Engineering evaporator. This arrangement results in an unpatterned layer of the organic compound being deposited onto the substrate surface when the organic compounds under test were evaporated from an Alumina crucible positioned inside a Radak furnace. After deposition of this layer, the evaporator was vented inside the glovebox and the substrates transferred to a drop-in shadow mask for the deposition of Gold source and drain electrodes, also with a source to substrate distance of approximately 0.5 m. Gold was evaporated from an open tungsten boat supplied by RD Mathis. The area defined by the shadow mask results in two transistor devices per substrate with the device dimensions of channel length and channel width of 60um and 2mm respectively.

Subsequent to these fabrication steps, the evaporator was vented and the completed devices were transferred, without exposure to air, to an electrical testing station in an adjacent glovebox.

In a region of the substrate laterally removed from the Source and Drain electrodes of the device, a Dremel drill was used to drill through the dielectric layer and into the underlying Gate electrode of the device. Silver paint was applied to this region so as to make an electrically conductive pathway between the Gate electrode and the contact pad formed by the Silver paint on top of the device. The device was then readied for measurement by making Gate, Source and Drain electrode connections to the Analyser by the use of Suss Microtech probes.

An Output' curve (I D-VD curve) was first measured by sweeping the drain voltage ( V _D ) between 0V and +80V at 1 .0V intervals for gate voltages ( V _G ) varied between and 0 and +80V at 10V intervals. A 'transfer' curve (I D-VG curve) was then measured in the forward and reverse directions by sweeping the gate voltage (V _G ) between -20 and +80V at 0.5V intervals (forward sweep) and then from +80V to -20V at intervals of -0.5V (reverse sweep) for drain voltages ( V _D ) of +40V to +80V at 10V intervals. The field effect electron mobility in the saturation regime _{e sa} f is calculated from the forward sweep of the transfer curve for a drain voltage of +80V by obtaining t of V/ _D against V _G and using the standard transistor equation:

in which C is the capacitance per unit area of the Si0 ₂ dielectric layer (10nF/cm ² ), and L and W are the device length and width respectively. Device Example 4

Compound 48 was used in a transistor as the electron transporting material on an OTS-treated Si02 surface. Film thicknesses of evaporated layers are shown in brackets.

Device structure: n-Si / OTS-treated Si02 / Compound 48 / Gold.

The Id-Vd and Id-Vg curves for one of the two devices on the substrate are shown in Figure 7 and 8 and are representative of both devices on the substrate. A value of 0.083 cm ² /Vs was calculated for the field effect electron mobility in the saturation regime for this device.

Device Example 5

Compound 48 was used in a transistor as the electron transporting material on an HMDS-treated Si02 surface.

Device structure: n-S\ I HMDS-treated Si02 / Compound 48/ Gold.

A value of 0.0026 cm ² /Vs was calculated for the field effect electron mobility in the saturation regime for this device.

Device Example 6

Compound 47 was used in a transistor as the electron transporting material on an OTS-treated Si02 surface.

Device structure: n-Si / OTS-treated Si02 / Compound 47 / Gold.

A value of 0.01 1 cm ² /Vs was calculated for the field effect electron mobility in the saturation regime for this device.

It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.