BACKGROUND

Organic light emitting diodes (OLEDs) are display devices that employ stacks of films containing organic aromatic compounds as electron transport layers (ETLs) and hole transport layers (HTLs). New material discovery for electron transport layer (ETL) and hole transport layers (HTL) in organic light emitting diodes (OLEDs) have been targeted to improve device performance and lifetimes. In the case of the HTL layer, the process by which the layer is deposited is critical for its end-use application. Methods for depositing the HTL layer, in small display applications, involve evaporation of a small organic compound with a fine metal mask to direct the deposition. In the case of large displays, this approach is not practical from a material usage and high throughput perspective. With these findings in mind, new processes are needed to deposit HTLs that satisfy these challenges, and which can be directly applied to large display applications.

One approach that appears promising is a solution process which involves the deposition of a small molecule followed by crosslinking or polymerization chemistry.

There have been extensive efforts in this area, along these lines; however these approaches have their own shortcomings. In particular, the mobility of the charges in the HTL layer becomes reduced, as a result of crosslinking or polymerization chemistry. This reduced hole mobility leads to poor device lifetime and difficulty in maintaining a charge balanced device. This imbalance can also lead to device efficiency issues.

Benzocyclobutene (BCB) chemistries and their use in OLEDs are described in the following: US20040004433, US20080315757, US20080309229, US20100133566, US20110095278, US20110065222, US20110198573, US20110042661, JP2010062120, US7893160, US20110089411, US20070181874, US20070096082, CN102329411, US20120003790, WO2012052704, WO2012175975, WO2013007966.

In the case of styrene-based chemistries, the use of the styrene moiety has been described in the following: US8283002B2; US20120049164A1; KR2012066149A

(Abstract); US20090321723A1; WO2011133007A2; JP2004303488A (Abstract);

US20080153019A1; WO2011062802A1; WO2009133753A1; US8343636B2; Jen et al., Chem. Mater. 2008, 20, 413-422; Kido et al., Organic Electronics, 2013, 14, 1614-1620; Meerholz et al., Adv. Funct. Mater. 2013, 23, 359-365. However, there remains a need for new compositions for improved hole-transporting materials, and for improved processing of the same. These needs have been met by the following invention. SUMMARY OF INVENTION

The invention provides a light emitting device comprising a polymeric charge transfer layer, wherein the polymeric charge transfer layer is formed from a composition comprising a polymer, said polymer comprising one or more polymerized units derived from Structure A, and one or more polymerized units derived from Structure B, each as follows:

A) a monomer having the Structure A:

(Structure A);

wherein, for Structure A, A is a substituted or unsubstituted aromatic moiety or a substituted or unsubstituted heteroaromatic moiety; and

wherein Rl through R3 are each independently selected from the following:

hydrogen, deuterium, a hydrocarbyl, a substituted hydrocarbyl, a heterohydrocarbyl, a substituted heterohydrocarbyl, a halogen, a cyano, an aryl, a substituted aryl, a heteroaryl, a substituted heteroaryl; and

wherein n is from 1 to 10; and each R4 is independently selected from the following: hydrogen, deuterium, a hydrocarbyl, a substituted hydrocarbyl, a heterohydrocarbyl, a substituted heterohydrocarbyl, a halogen, a cyano, an aryl, a substituted aryl, a heteroaryl, a substituted heteroaryl; and wherein each R4 group is independently bonded to A; and

wherein O is oxygen; and

wherein Q is selected from the following: hydrogen, deuterium, a hydrocarbyl, a substituted hydrocarbyl, a heterohydrocarbyl, a substituted heterohydrocarbyl, a halogen, a cyano, an aryl, an substituted aryl, a heteroaryl, a substituted heteroaryl; and

wherein two or more of Rl through R4 may optionally form one or more ring structures; and

B) a monomer that comprises one or more dienophile moieties. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts strip data on films formed from inventive compositions.

Figure 2 depicts the DSC profile of HTL-SP-8.

Figure 3 depicts the DSC profile of HTL-SP-3.

Figure 4 depicts the DSC profile of HTL-SP-8 and HTL-SP-3.

Figure 5 depicts the MALDI-TOF profile of the film produced by heating HTL-SP-3 and HTL-SP-8 at 190°C.

Figure 6 depicts an expanded MALDI-TOF profile of the film produced by heating HTL-SP-3 and HTL-SP-8 at 190°C.

DETAILED DESCRIPTION

It has been discovered inventive composition for use for hole transporting materials that mitigate these drawbacks of the art. It has been discovered that by using one attachment point on the molecule, we can minimize the energy required for rearrangement during oxidation. Furthermore, this flexibility will also lead to more efficient chain stacking which can bring the molecular cores into close proximity to each other. This approach will improve hole transport in the HTL layer via thru-space interactions. Furthermore, the chemistry described in this invention can also satisfy temperature and time considerations relating to desirable process conditions. See, for example, schematic 1 below. l

Crosslinked HTL

Film

P>1 = -OR ₉

Schematic 1

In comparison to other prior art that utilizes BCB chemistry, it has been discovered invention describes chemistry that would occur at substantially lower temperatures. It is been documented in the open literature that the substitution of oxygen-based donors at the R1-R4 positions above has a dramatic effect on the ring-opening temperature of the BCB (Dobish, J.N.; Hamilton, S.K.; Harth, E. Polymer Chemistry 2012, 3, 857-860); this phenomenon has yet to be utilized for OLED-based applications. With unsubstituted BCB derivatives, the ring opening temperatures has been noted to occur at temperatures of approximately 250°C (Kirchhoff, R.A.; Bruza, K.J. Progress in Polymer Science 1993, 18, 85-185). In this invention, the substitution of an oxygen donor results in a significant reduction in the ring opening temperatures to values between 100-120 °C which has significant process advantages over previous inventions. Once a reactive o-quinodimethane moiety has been formed, Diels- Alder reactions can occur to generate new C-C bonds in either a 1- or 2-component approach. Furthermore, the two-component approach with a reactive o-quinodimethane moiety and polydienophile has yet to be reported in the IP landscape.

It has been discovered that the inventive composition can be used as hole

transporting materials in OLEDs and achieves high efficiency without second organic charge transport compound.

It has been discovered that the inventive composition can be used be used as hole transporting layers in solution-processed OLEDs.

It has been discovered that the inventive composition can be used as hole

transporting materials in OLED devices.

It has been discovered that an inventive film can be cross linked thermally and/or with radiation, and further without a crosslinking agent.

As discussed above, the invention provides a light emitting device comprising a polymeric charge transfer layer, wherein the polymeric charge transfer layer is formed from a composition comprising a polymer, said polymer comprising one or more polymerized units derived from Structure A, and one or more polymerized units derived from Structure B, each as follows:

A) a monomer having the Structure A:

(Structure A);

wherein, for Structure A, A is a substituted or unsubstituted aromatic moiety or a substituted or unsubstituted heteroaromatic moiety; and

wherein Rl through R3are each independently selected from the following:

hydrogen; deuterium; a hydrocarbyl, further a Ci-Cioo hydrocarbyl, further a C3-C100 hydrocarbyl, further a C10-C100 hydrocarbyl, further a C20-C100 hydrocarbyl, further a C30- Cioo hydrocarbyl; a substituted hydrocarbyl, further a C1-C100 substituted hydrocarbyl, further a C3-C100 substituted hydrocarbyl, further a C10-C100 substituted hydrocarbyl, further a C20-C100 substituted hydrocarbyl, further a C ₃₀ -Cioo substituted hydrocarbyl; a

heterohydrocarbyl, further a C1-C100 heterohydrocarbyl, further a C3-C100 heterohydrocarbyl, further a C10-C100 heterohydrocarbyl, further a C20-C100 heterohydrocarbyl, further a C ₃₀ - Cioo heterohydrocarbyl; a substituted heterocarbyl, further a C1-C100 substituted

heterohydrocarbyl, further a C ₃ -Ci ₀ o substituted heterohydrocarbyl, further a C10-C100 substituted heterohydrocarbyl, further a C20-C100 substituted heterohydrocarbyl, further a C ₃ o-Cioo substituted heterohydrocarbyl; a halogen; a cyano; an aryl, further a C5-C100 aryl, further a C ₆ -Cioo aryl, further a C10-C100 aryl, further a C20-C100 aryl, further a C ₃ o-Cioo aryl; a substituted aryl, further a C5-C100 substituted aryl, further a C ₆ -Cioo substituted aryl, further a C10-C100 substituted aryl, further a C20-C100 substituted aryl, further a C ₃₀ -Ci ₀ o substituted aryl; a heteroaryl, further a C5-C100 heteroaryl, further a C ₆ -Cio heteroaryl further a C10-C100 heteroaryl, further a C20-C100 heteroaryl, further a C ₃ o-Cioo heteroaryl; a substituted heteroaryl, further a C5-C100 substituted heteroaryl, further a C ₆ -Cioo substituted heteroaryl, further a C10-C100 substituted heteroaryl, further a C20-C100 substituted heteroaryl, further a C ₃₀ -Ci ₀ o substituted heteroaryl; and

wherein n is from 1 to 10; and each R4 is independently selected from the following: hydrogen; deuterium; a hydrocarbyl, further a C1-C100 hydrocarbyl, further a C ₃ -Cioo hydrocarbyl, further a C10-C100 hydrocarbyl, further a C20-C100 hydrocarbyl, further a C ₃₀ - Cioo hydrocarbyl; a substituted hydrocarbyl, further a C1-C100 substituted hydrocarbyl, further a C ₃ -Ci ₀ o substituted hydrocarbyl, further a C10-C100 substituted hydrocarbyl, further a C20-C100 substituted hydrocarbyl, further a C ₃ o-Cioo substituted hydrocarbyl; a

heterohydrocarbyl, further a C1-C100 heterohydrocarbyl, further a C ₃ -Cioo heterohydrocarbyl, further a C10-C100 heterohydrocarbyl, further a C20-C100 heterohydrocarbyl, further a C ₃₀ - Cioo heterohydrocarbyl; a substituted heterohydrocarbyl, further a C1-C100 substituted heterohydrocarbyl, further a C ₃ -Cioo substituted heterohydrocarbyl, further a C10-C100 substituted heterohydrocarbyl, further a C20-C100 substituted heterohydrocarbyl, further a C ₃ o-Cioo substituted heterohydrocarbyl; a halogen; a cyano; an aryl, further a C5-C100 aryl, further a C ₆ -Cioo aryl, further a C10-C100 aryl, further a C20-C100 aryl, further a C ₃ o-Cioo aryl; a substituted aryl, further a C5-C100 substituted aryl, further a C ₆ -Cioo substituted aryl, further a C10-C100 substituted aryl, further a C20-C100 substituted aryl, further a C ₃₀ -Cioo substituted aryl; a heteroaryl, further a C5-C100 heteroaryl, further a C ₆ -Cio heteroaryl further a C10-C100 heteroaryl, further a C20-C100 heteroaryl, further a C ₃ o-Cioo heteroaryl; a substituted heteroaryl, further a C5-C100 substituted heteroaryl, further a C ₆ -Cioo substituted heteroaryl, further a C10-C100 substituted heteroaryl, further a C20-C100 substituted heteroaryl, further a C30-C100 substituted heteroaryl; and wherein each R4 group is independently bonded to A; and

wherein O is oxygen; and

wherein Q is selected from the following: hydrogen; deuterium; a hydrocarbyl, further a C1-C100 hydrocarbyl, further a C3-C100 hydrocarbyl, further a C10-C100 hydrocarbyl, further a C20-C100 hydrocarbyl, further a C30-C100 hydrocarbyl; a substituted hydrocarbyl, further a C1-C100 substituted hydrocarbyl, further a C3-C100 substituted hydrocarbyl, further a Cio-Cioo substituted hydrocarbyl, further a C20-C100 substituted hydrocarbyl, further a C30- C100 substituted hydrocarbyl; a heterocarbyl, further a C1-C100 heterohydrocarbyl, further a C3-C100 heterohydrocarbyl, further a C10-C100 heterohydrocarbyl, further a C20-C100 heterohydrocarbyl, further a C30-C100 heterohydrocarbyl; a substituted heterohydrocarbyl, further a C1-C100 substituted heterohydrocarbyl, further a C3-C100 substituted

heterohydrocarbyl, further a C10-C100 substituted heterohydrocarbyl, further a C20-C100 substituted heterohydrocarbyl, further a C ₃₀ -Cioo substituted heterohydrocarbyl; a halogen; a cyano; a aryl, further a C5-C100 aryl, further a C ₆ -Cioo aryl, further a C10-C100 aryl, further a C20-C100 aryl, further a C30-C100 aryl; a substituted aryl, a C5-C100 substituted aryl, further a C ₆ -Cioo substituted aryl, further a C10-C100 substituted aryl, further a C20-C100 substituted aryl, further a C30-C100 substituted aryl; a heteroaryl, further a C5-C100 heteroaryl, further a C ₆ -Cio heteroaryl further a C10-C100 heteroaryl, further a C20-C100 heteroaryl, further a C ₃₀ - C100 heteroaryl; a substituted heteroaryl, further a C5-C100 substituted heteroaryl, further a C ₆ -Cioo substituted heteroaryl, further a C10-C100 substituted heteroaryl, further a C20-C100 substituted heteroaryl, further a C30-C100 substituted heteroaryl; and

wherein two or more of Rl through R4 may optionally form one or more ring structures; and

B) a monomer that comprises one or more dienophile moieties

An inventive device may comprise a combination of two or more embodiments as described herein.

As used herein, Rl = Ri, R2 = R ₂ , R3 = R ₃ , and so forth.

Substituents include, but are not limited to, OR', R' ₂ , PR' 2, P(=0)R' ₂ , SiR' ₃ ;

where each R' is a C30-C100 hydrocarbyl group. In one embodiment, monomer of component B is selected from a structure of

Structure B:

(Structure B),

wherein, for Structure B, B is a substituted or unsubstituted aromatic moiety or a substituted or unsubstituted heteroaromatic moiety; and

wherein R5 through R7 are each independently selected from the following:

hydrogen, deuterium, a C ₆ -Cioo hydrocarbon, a substituted C ₆ -Cioo hydrocarbon, a halogen, a cyano, an unsubstituted C ₆ -Ci ₀ o arylene, a substituted C ₆ -Ci ₀ o arylene, an unsubstituted C ₆ -Cioo heteroarylene, a substituted C ₆ -Cioo substituted arylene, OR', R' ₂ , PR' ₂ , P(=0)R' ₂ , SiR' ₃ where each R' is a Ci-C ₂₀ hydrocarbyl group, and

wherein two or more of R5, R6 and/or R7 may optionally form one or more ring structures.

In one embodiment, for Structure B, R5 through R7 are each independently selected from the following: hydrogen, deuterium, a C ₆ -Cioo hydrocarbon, a substituted C ₆ -Cioo hydrocarbon, a halogen, a cyano, an unsubstituted C ₆ -Cioo arylene, a substituted C ₆ -Cioo arylene, an unsubstituted C ₆ -Cioo heteroarylene, a substituted C ₆ -Cioo substituted arylene, OR', R' ₂ , PR' ₂ , P(=0)R' ₂ , SiR' ₃ where each R' is a Ci-C ₂₀ hydrocarbyl group.

In one embodiment, the polymer further comprises one or more polymerized units derived from a cross-linkin agent having Structure C:

(Structure C), wherein, for Structure C, C is an aromatic moiety, a heteroaromatic moiety, a C1-C50 hydrocarbyl, a Ci-C ₅₀ substituted hydrocarbyl, a Ci-C ₅₀ heterohydrocarbyl, or a Ci-C ₅₀ substituted heterohydrocarbyl,; and

wherein R8 through RIO are each independently selected from the following:

hydrogen, deuterium, a C1-C50 hydrocarbyl, a C1-C50 substituted hydrocarbyl, a C1-C50 heterohydrocarbyl, a C1-C50 substituted heterohydrocarbyl, halogen, cyano, a C5-C50 aryl, a C5-C50 substituted aryl, a C ₅ -C ₅₀ heteroaryl, a C ₅ -C ₅₀ substituted heteroaryl; and wherein n is from 1 to 25; and wherein each "chemical group comprising L, R8, R9 and RIO" is independently boned to C;

wherein L is selected from an aromatic moiety, a heteroaromatic moiety, a Ci-Cioo hydrocarbyl, a CI -CI 00 substituted hydrocarbyl, a CI -CI 00 heterohydrocarbyl, or a Cl- C100 substituted heterohydrocarbyl;

wherein two or more of R8 through R10 may optionally form one or more ring structures.

In one embodiment, the cross-linking agent selected from the following C I- C8:

In one embodiment, the crosslinking agent is present in an amount from greater than 0 to 20 mole%, further from greater than 0 to 10 mole%, based on the sum moles of Structure A, Structure B and cross-linking agent (Structure C).

In one embodiment, the molar ratio of Structure A to Structure B is from 0.8 to 1.2, further from 0.9 to 1.1.

In one embodiment, the monomer of component B is selected from the following B l through B4:

embodiment, Stmcture A is selected from the following Al through A8

embodiment, Structure A is selected from the following A9 through A14:

wherein for each structure A9 through A14, L is independently selected from igen, a hydrocarbon, or a substituted hydrocarbon.

In one embodiment, Structure A is selected from the following A15 through A20:

The invention also provides a composition comprising a polymer, which comprises, as polymerized units, the following:

A) a monomer having the Structure A:

(Structure A);

wherein Structure A is defined above; and

B) a monomer that comprises one or more dienophile moieties.

In one embodiment, monomer of component B is selected from a structure of Structure B:

(Structure B),

wherein, for Structure B, B is a substituted or unsubstituted aromatic moiety or a substituted or unsubstituted heteroaromatic moiety; and

wherein R5 through R7 are each independently selected from the following:

hydrogen, deuterium, a C ₆ -Cioo hydrocarbon, a substituted C ₆ -Cioo hydrocarbon, a halogen, a cyano, an unsubstituted C ₆ -Cioo arylene, a substituted C ₆ -Cioo arylene, an unsubstituted C ₆ -Cioo heteroarylene, a substituted C ₆ -Ci ₀ o substituted arylene, OR', R' ₂ , PR' ₂ , P(=0)R' ₂ , SiR' ₃ where each R' is a C ₆ -Ci ₀ o hydrocarbyl group, and

wherein two or more of R5, R6 and/or R7 may optionally form one or more ring structures.

In one embodiment, the polymer further comprises one or more polymerized units derived from a cross-linkin agent having the Structure C:

(Structure C), wherein, for Structure C, C is an aromatic moiety, a heteroaromatic moiety, a C ₁ -C ₅₀ hydrocarbyl, a Ci-C ₅₀ substituted hydrocarbyl, a Ci-C ₅₀ heterohydrocarbyl, or a Ci-C ₅₀ substituted heterohydrocarbyl,; and

wherein R8 through RIO are each independently selected from the following:

hydrogen, deuterium, a C1-C50 hydrocarbyl, a C1-C50 substituted hydrocarbyl, a C1-C50 heterohydrocarbyl, a Ci-C ₅₀ substituted heterohydrocarbyl, halogen, cyano, a C ₅ -C ₅₀ aryl, a C5-C50 substituted aryl, a C ₅ -C ₅₀ heteroaryl, a C ₅ -C ₅₀ substituted heteroaryl; and

wherein n is from 1 to 25; and wherein each "chemical group comprising L, R8, R9 and RIO" is independently boned to C;

wherein L is selected from an aromatic moiety, a heteroaromatic moiety, a C ₁ -C ₁₀₀ hydrocarbyl, a C ₁ -C ₁₀₀ substituted hydrocarbyl, a C ₁ -C ₁₀₀ heterohydrocarbyl, or a C ₁ -C ₁₀₀ substituted heterohydrocarbyl,;

wherein two or more of R8 through RIO may optionally form one or more ring structures.

In one embodiment, the cross-linking agent selected from the following CI- C8:

In one embodiment, the crosslinking agent is present in an amount from greater than 0 to 20 mole%, further from greater than 0 to 10 mole%, based on the sum moles of Structure A, Structure B and cross-linking agent.

In one embodiment, the molar ratio of Structure A to Component B is from 0.8 to 1.2, further from 0.9 to 1.1.

In one embodiment, the monomer of component B is selected from the following B 1 through

In one embodiment, Structure A is selected from the following Al through A8

embodiment, Structure A is selected from the following A9 through A14:

wherein for each structure A9 through A14, L is independently selected from igen, a hydrocarbon, or a substituted hydrocarbon.

In one embodiment, Structure A is selected from the following A15 through A20:

In one embodiment, Structure A has a molecular weight from 200 g/mole to 5,000 g/mole, further from 300 g/mole to 4,000 g/mole.

In one embodiment, the Structure B has a molecular weight from 400 g/mole to

2,000 g/mole, further from 500 g/mole to 1,000 g/mole.

The invention also provides a hole transporting solution-processed layer formed from an inventive composition as described herein, including a composition of one or more embodiments as described herein.

In one embodiment, the hole transporting solution-processed layer is prepared in an inert atmosphere with less than 50 ppm of 02, based on total weight of components in atmosphere.

In one embodiment, the hole transporting solution-processed layer is formed from a solution coating onto a substrate, and wherein the coating is baked (thermally treated) at a temperature greater than, or equal to, 75 degrees Celsius. In a further embodiment, the coating is baked at a temperature from 75 to 300 degrees Celsius. In a further embodiment, the coating is contacted with a heat source to facilitate chemical reactions which lead to an increase in the molecular weight of the molecules of the polymer.

In one embodiment, the hole transporting solution-processed layer is insoluble in anisole.

In one embodiment, the hole transporting solution-processed layer shows less than 1 nm removal, following contact with anisole at 23 degrees Celsius, for 60 seconds.

In one embodiment, the hole transporting solution-processed layer is overcoated with another solvent-borne organic material, to form two layers with an intermixed interface between these layers, and wherein the thickness of the intermixed interface is less than 1 nm.

The hole transporting solution-processed layer may comprise a combination of two or more embodiments as described herein. The invention also provides a hole injection solution-processed layer formed from an inventive composition as described herein, including a composition of one or more embodiments as described herein.

The hole injection solution-processed layer may comprise a combination of two or more embodiments as described herein.

The invention also provides an emissive solution-processed layer formed from an inventive composition as described herein, including a composition of one or more embodiments as described herein.

The emissive solution-processed layer may comprise a combination of two or more embodiments as described herein.

The invention also provides an electronic device comprising an inventive hole transporting solution-processed layer, as described herein, or an inventive hole transporting solution-processed layer of one or more embodiments described herein.

The invention also provides an electronic device comprising an inventive hole injection solution-processed layer, as described herein, or an inventive hole injection solution-processed layer of one or more embodiments described herein.

The invention also provides an electronic device comprising an inventive emissive solution-processed layer, as described herein, or an inventive emissive solution-processed layer of one or more embodiments described herein.

The invention also provides a film comprising at least one Layer A formed from an inventive composition.

The invention also provides an article comprising at least one component formed from an inventive composition.

In one embodiment, the article is an electroluminescent device.

The invention also provides an article comprising at least one component formed from an inventive film.

In one embodiment, the article is an electroluminescent device.

An inventive article may comprise a combination of two or more embodiments described herein.

An inventive composition may comprise a combination of two or more

embodiments described herein. DEFINITIONS

The term "dienophile," as used herein, refers to a molecule that possesses 2 π- electrons, and which can participate in Diels-Alder cycloaddition reactions. Examples of this include, but are not limited to, alkenes, alkynes, nitriles, enol ethers, and enamines.

The term "dienophile moiety," as used herein, refers to a chemical group that possesses 2 π-electrons, and which can participate in Diels-Alder cycloaddition

reactions. Examples include, but are not limited to, alkenes, alkynes, nitriles, enol ethers, and enamines.

As used herein, the term "light emitting device," as used herein, refers to a device that emits light when an electrical current is applied across two electrodes.

As used herein, the term "polymeric charge transfer layer," as used herein, refers to a polymeric material that can transport charge carrying moieties, either holes or electrons.

As used herein, the term "cross-linking monomer," as used herein, refers to an organic or inorganic molecule that can join adjacent chains of a polymer by creating covalent bonds.

As used herein, the term "hole transporting solution-processed layer," as used herein, refers to a hole transporting layer which can be processed by solution-based methods, such as spin-coating, inkjet printing, and screen printing.

As used herein, the term "hole injection solution-processed layer," as used herein, refers to a hole injection layer which can be processed by solution-based methods, such as spin-coating, inkjet printing, and screen printing.

As used herein, the term "emissive solution-processed layer," as used herein, refers to an emissive layer which can be processed by solution-based methods, such as spin- coating, inkjet printing, and screen printing.

As used herein, the term "electron transporting solution-processed layer," as used herein, refers to an electron transporting layer which can be processed by solution-based methods, such as spin-coating, inkjet printing, and screen printing.

As used herein, the term "solvent-borne organic material," as used herein, refers to an organic compound that is dissolved or suspended in a solvent whereby the solvent can be made volatile and evaporated.

As used herein, the term "electronic device," as used herein, refers to a device which depends on the principles of electronics and uses the manipulation of electron flow for its operation. As used herein, the term "charge transporting film," as used herein, refers to a film whereby charge is transported either intra- or inter-molecularly between one or more molecules

The term "hydrocarbyl," as used herein, refers to a chemical group containing only hydrogen and carbon atoms.

The term "substituted hydrocarbyl," as used herein, refers to a hydrocarbyl in which at least one hydrogen atom is substituted with a heteroatom or a chemical group containing at least one heteroatom. Heteroatoms include, but are not limited to, O, N, P and S.

Substituents include, but are not limited to, OR', R' ₂ , PR' ₂ , P(=0)R' ₂ , SiR' ₃ ; where each R' is a C ₃ o-Cioo hydrocarbyl group.

The term "heterohydrocarbyl," as used herein, refers to a chemical group containing hydrogen and carbon atoms, and wherein at least one carbon atom or CH group or CH2 group is substituted with a heteroatom or a chemical group containing at least one heteroatom. Heteroatoms include, but are not limited to, O, N, P and S.

The term "substituted heterohydrocarbyl," as used herein, refers to a

heterohydrocarbyl in which at least one hydrogen atom is substituted with a heteroatom or a chemical group containing at least one heteroatom. Heteroatoms include, but are not limited to, O, N, P and S. Substituents include, but are not limited to, OR', R' ₂ , PR' ₂ , P(=0)R' ₂ , SiR' ₃ ; where each R' is a C ₃ o-Cioo hydrocarbyl group.

The term "aromatic moiety, " as described herein, refers to an organic moiety derived from aromatic hydrocarbon by deleting at least one hydrogen atom therefrom. An aromatic moiety may be a monocyclic and/or fused ring system, each ring of which suitably contains from 4 to 7, preferably from 5 or 6 atoms. Structures wherein two or more aromatic moieties are combined through single bond(s) are also included. Specific examples include, but are not limited to, phenyl, naphthyl, biphenyl, anthryl, indenyl, fluorenyl, benzofluorenyl, phenanthryl, triphenylenyl, pyrenyl, perylenyl, chrysenyl, naphtacenyl, fluoranthenyl and the like, but are not restricted thereto. The naphthyl may be 1 -naphthyl or 2-naphthyl, the anthryl may be 1 -anthryl, 2-anthryl or 9-anthryl, and the fluorenyl may be any one of 1 -fluorenyl, 2-fluorenyl, 3 -fluorenyl, 4-fluorenyl and 9- fluorenyl.

The term "heteroaromatic moiety, " as described herein, refers to an aromatic moiety, in which at least one carbon atom or CH group or CH ₂ group is substituted with a

heteroatom (for example, B, N, O, S, P(=0), Si and P) or a chemical group containing at least one heteroatom. The heteroaromatic moiety may be a 5- or 6-membered monocyclic heteroaryl, or a polycyclic heteroaryl which is fused with one or more benzene ring(s), and may be partially saturated. The structures having one or more heteroaromatic moieties bonded through a single bond are also included. Specific examples include, but are not limited to, monocyclic heteroaryl groups, such as furyl, thiophenyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazanyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl;

polycyclic heteroaryl groups, such as benzofuranyl, fluoreno[4, 3-b]benzofuranyl, benzothiophenyl, fluoreno[4, 3-b]benzothiophenyl, isobenzofuranyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothia- diazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenanthridinyl and benzodioxolyl.

The term "aryl" as described herein, refers to an organic radical derived from aromatic hydrocarbon by deleting one hydrogen atom therefrom. An aryl group may be a monocyclic and/or fused ring system, each ring of which suitably contains from 4 to 7, preferably from 5 or 6 atoms. Structures wherein two or more aryl groups are combined through single bond(s) are also included. Specific examples include, but are not limited to, phenyl, naphthyl, biphenyl, anthryl, indenyl, fluorenyl, benzofluorenyl, phenanthryl, triphenylenyl, pyrenyl, perylenyl, chrysenyl, naphtacenyl, fluoranthenyl and the like, but are not restricted thereto. The naphthyl may be 1 -naphthyl or 2-naphthyl, the anthryl may be 1- anthryl, 2-anthryl or 9-anthryl, and the fluorenyl may be any one of 1 -fluorenyl, 2-fluorenyl, 3 -fluorenyl, 4-fluorenyl and 9-fluorenyl.

The term "substituted aryl," as used herein, refers to an aryl in which at least one hydrogen atom is substituted with a heteroatom or a chemical group containing at least one heteroatom. Heteroatoms include, but are not limited to, O, N, P and S. Substituents include, but are not limited to, OR', R' ₂ , PR' ₂ , P(=0)R' ₂ , SiR' ₃ ; where each R' is a Ci-C ₂₀ hydrocarbyl group.

The terms "heteroaryl" as described herein, refers to an aryl group, in which at least one carbon atom or CH group or CH ₂ group is substituted with a heteroatom (for example, B, N, O, S, P(=0), Si and P) or a chemical group containing at least one heteroatom. The heteroaryl may be a 5- or 6-membered monocyclic heteroaryl or a polycyclic heteroaryl which is fused with one or more benzene ring(s), and may be partially saturated. The structures having one or more heteroaryl group(s) bonded through a single bond are also included. The heteroaryl groups may include divalent aryl groups of which the heteroatoms are oxidized or quarternized to form N-oxides, quaternary salts, or the like. Specific examples include, but are not limited to, monocyclic heteroaryl groups, such as furyl, thiophenyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazanyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl; polycyclic heteroaryl groups, such as benzofuranyl, fluoreno[4, 3- b]benzofuranyl, benzothiophenyl, fluoreno[4, 3-b]benzothiophenyl, isobenzofuranyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothia- diazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenanthridinyl and benzodioxolyl; and corresponding N-oxides (for example, pyridyl N-oxide, quinolyl N-oxide) and quaternary salts thereof.

The term "substituted heteroaryl," as used herein, refers to a heteroaryl in which at least one hydrogen atom is substituted with a heteroatom or a chemical group containing at least one heteroatom. Heteroatoms include, but are not limited to, O, N, P and S.

Substituents include, but are not limited to, OR', R' ₂ , PR' ₂ , P(=0)R' ₂ , SiR' ₃ ; where each R' is a Ci-C ₂₀ hydrocarbyl group.

The term "polymer," as used herein, refers to a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term homopolymer (employed to refer to polymers prepared from only one type of monomer, with the understanding that trace amounts of impurities can be incorporated into and/or within the polymer structure), and the term interpolymer as defined hereinafter.

The term "interpolymer," as used herein, refers to polymers prepared by the polymerization of at least two different types of monomers. The generic term interpolymer thus includes copolymers (employed to refer to polymers prepared from two different types of monomers), and polymers prepared from more than two different types of monomers.

EXPERIMENTAL

Reagents and Test Methods

All solvents and reagents were obtained from commercial vendors (for example,

Sigma-Aldrich, TCI, and Alfa Aesar) and were used in the highest available purities, and/or when necessary, recrystallized before use. Dry solvents were obtained from in-house purification/dispensing system (hexane, toluene, and tetrahydrofuran), or purchased from Sigma-Aldrich. All experiments involving "water sensitive compounds" were conducted in "oven dried" glassware, under nitrogen atmosphere, or in a glovebox. Reactions were monitored by analytical, thin-layer chromatography (TLC) on precoated aluminum plates (VWR 60 F254), and visualized by UV light and/or potassium permanganate staining. Flash chromatography was performed on an ISCO COMBIFLASH system with

GRACERESOLV cartridges.

¹ H- MR-spectra (500 MHz or 400 MHz) were obtained on a Varian V MRS-500 or V MRS-400 spectrometer, at 30°C, unless otherwise noted. The chemical shifts were referenced to TMS (5=0.00) in CDC1 ₃ .

1 ³ C- MR spectra (125 MHz or 100 MHz) were obtained on a Varian VNMRS-500 or VNRMS-400 spectrometer, and referenced to TMS (5=0.00) in CDC1 ₃ .

Routine LC/MS studies were carried out as follows. Five microliter aliquots of the sample, as "3 mg/ml solution in THF," were injected on an AGILENT 1200SL binary gradient, liquid chromatography, coupled to an AGILENT 6520 QTof, quadruple-time of flight MS system, via a dual spray electrospray (ESI) interface, operating in the PI mode. The following analysis conditions were used: column: 150 x 4.6 mm ID, 3.5 μιη ZORBAX SB-C8; column temperature: 40°C; mobile phase: 75/25 A/B to 15/85 A/B at 40 minutes; solvent A = 0.1v% formic acid in water; solvent B = THF; flowl .O mL/min; UV detection: diode array 210 to 600 nm (extracted wavelength 250,280nm); ESI conditions: gas temperature 365°C; gas flow - 8ml/min; capillary - 3.5 kV; nebulizer - 40PSI; fragmentor - 145V.

DSC was done using a 2000 instrument at a scan rate of 10°C/min, and in a nitrogen atmosphere for all cycles. The sample (about 7-10 mg) was scanned from room temperature to 300°C, cooled to - 60°C, and reheated to 300°C. The glass transition temperature (T _g ) was measured on the second heating scan. Data analysis was performed using TA

Universal Analysis software. The T _g was calculated using the "mid-point of inflection" methodology.

MALDI-TOF Measurements: All samples were analyzed using a Bruker

UltrafleXtreme MALDI-TOF/TOF MS (Bruker Daltronics Inc., Billerica, MA), equipped with a 355-nm Nd:YAG laser. Spectra were obtained in the positive ion reflection mode, with a mass resolution greater than 20,000 full-width, at half-maximum height (fwhm). The isotopic resolution was observed throughout the entire mass range detected; and the laser intensity was set approximately 10% greater than threshold. Instrument voltages were optimized for each spectrum to achieve the best signal-to-noise ratio. External mass calibration was performed using protein standards (Peptide Mix II) from a Peptide Mass Standard Kit (Bruker Daltronics), and a seven-point calibration method using Bradykinin (clip 1-7) (m = 757.40 Da), Angiotensin II (m = 1046.54 Da), Angiotensin I (m = 1296.68 Da), Substance P (m = 1347.74 Da), ACTH (clip 1-17) (m = 2093.09 Da), ACTH (clip 18- 39) (m = 2465.20 Da), and Somatostatin 28 (m = 3147.47 Da), to yield monoisotopic mass accuracy better than Am = ± 0.05 Da. The instrument was calibrated before each measurement to ensure constant experimental conditions.

Polymer samples were prepared using the evaporation-grinding method, in which a 2 mg sample of polymer was ground to a fine powder with 60 μΙ_, of distilled

tetrahydrofuran (THF, Fisher), in an agate mortar and pestle. The molar ratios of matrix:NaTF A:polymer were 25: 1 : 1. The mixture was then ground a second time to ensure homogeneity. A sample of the mixture was then pressed into a sample well, by spatula, on the MALDI sample plate. MS and MS/MS data were processed using Polymerix 2.0 software supplied by Sierra Analytics (Modesto, CA).

Synthesis of l,3-bis(bicyclo[4.2.0]octa-l(6),2,4-trien-7-yloxy)-5-iodoben zene

To a flask, charged with 3-iodoresorcinol (1 equiv) and K ₂ C0 ₃ (4 equiv), was added DMF. The solution was stirred at room temperature and 7-bromobicyclo[4.2.0]octa-l,3,5- triene (2.5 equiv) was added dropwise as a DMF solution. The mixture was heated to 70 °C for two days. After cooling to room temperature, the mixture was poured into water (100 mL), and extracted several times with diethyl ether. The organic fractions were collected, washed with brine, and dried with MgS0 ₄ . The organic fraction was filtered, and the solvent removed to provide a yellow oil. After recrystallization from methanol, a pale yellow solid was recovered; this was identified by NMR spectroscopy and consistent with the formation of the product. Synthesis of N-([l,l'-biphenyl]-4-yl)-N-(4-bromophenyl)-9,9-dimethyl-9H-f luoren-2- amine

To a flask, charged with N-([l, -biphenyl]-4-yl)-9,9-dimethyl-9H-fluoren-2-amine (1.0 equiv), 1,4-dibromobenzene (2.0 equiv), Pd2dba3 (0.02 equiv), tri-ortho-toluyl phosphine (0.06 equiv) and sodium tert-butoxide (2.0 equiv), was added toluene. The mixture was heated to reflux for 18 hours. The reaction was cooled to 25 °C, and washed with water and brine. The organic phase was dried over MgS0 ₄ , and concentrated. The resulting residue was purified via silica gel column, to afford the desired product as a white solid.

Synthesis of 3-bromo-9H-carbazole

The compound was synthesized using a previously published procedure described Midya et al. Chem. Commun. 2010, 46, 2091, incorporated herein by reference.

Synthesis of 3-(4,4,5,5-tetrameth -l,3,2-dioxaborolan-2-yl)-9H-carbazole:

The compound was synthesized using a previously published procedure described in U.S. Patent Publication US2005/0137204 Al, incorporated herein by reference. Synthesis of N-(4-(9H-carbazol-3-yl)phenyl)-N-([l,l'-biphenyl]-4-yl)-9,9- dimethyl-9H- fluoren- -amine

To a flask charged with N-([l, -biphenyl]-4-yl)-N-(4-bromophenyl)-9,9-dimethyl- 9H-fluoren-2-amine (1.2 equiv) and palladium tetrakis(triphenylphsophine) (0.03 equiv), in toluene (0.2 M), under N ₂ , was added 3-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-9H- carbazole (1.0 equiv), in ethanol (0.17 M), and an aqueous potassium carbonate solution (4.0 equiv, 2.0 M). The mixture was heated to 90°C for 12 hours. The reaction was cooled to 25 °C, and concentrated under vacuum. The resulting residue was diluted into methylene chloride, and washed with water. The organic phase was dried over Na ₂ SC"4, and concentrated. The resulting residue was purified via silica gel chromatography to afford the desired product as a white solid.

Synthesis of N-([l,l'-biphenyl]-4-yl)-N-(4-(9-(3,5-bis(bicyclo[4.2.0]octa -l(6),2,4-trien-7- yloxy)phenyl)-9H-carbazol-3-yl)phenyl)-9,9-dimethyl-9H-fluor en-2-amine:

To a flask charged with N-(4-(9H-carbazol-3-yl)phenyl)-N-([l, l'-biphenyl]-4-yl)- 9,9-dimethyl-9H-fluoren-2-amine(l equiv), l,3-bis(bicyclo[4.2.0]octa-l(6),2,4-trien-7- yloxy)-5-iodobenzene (1.1 equiv), copper iodide (0.25 equiv), and K ₃ PO ₄ (3 equiv) was added dioxane. The mixture was stirred for five minutes, and N,N'-dimethylcyclohexane- 1,2-diamine (0.5 equiv) added dropwise to the stirring mixture. The mixture was heated to 70°C for two days. After cooling to room temperature, the solvent was removed by rotary evaporation and extracted with CH ₂ C1 ₂ and water. The aqueous volume was further extracted with CH ₂ C1 ₂ twice. The organic fractions were combined, washed with brine, and dried with MgS0 ₄ . The organic fractions were filtered, and the solvent removed to yield the crude product. The resulting residue was purified via silica gel chromatography to afford the desired product as a white solid HTL-SP-8.

Synthes -([l,l'-biphenyl]-4-yl)-9,9-dimethyl-N-phenyl-9H-fluoren-2-a mine

N-([l,r-biphenyl]-4-yl)-9,9-dimethyl-9H-fluoren-2-amine (40.0 g, 110 mmol), bromobenzene (23.4 g, 150 mmol), Pd(OAc) ₂ (616 mg, 2.75 mmol), X-Phos (1.57 g, 3.3 mmol), iBuOK (24.6 g, 220 mmol) were added into a 250 mL, three-necked round-bottom flask, equipped with a reflux condenser. After addition of 250 mL dry toluene under N ₂ atmosphere, the suspension was heated to 90°C, and stirred overnight under a flow of N ₂ . After cooling to room temperature, water was added, and the organic layer was separated. The solvent was evaporated under vacuum, and the residue was used for the next step without further purification (yield: 95%). MS (ESI): 437.02 [M+H] ⁺ .

Synthesis of N-([l,l'-biphenyl]-4-yl)-N-(4-bromophenyl)-9,9-dimethyl-9H-f luoren-2- amine

To a solution of N-([l, l'-biphenyl]-4-yl)-9,9-dimethyl-N-phenyl-9H-fluoren-2- amine (1) (35.0 g, 80 mmol) in 150 mL DMF, N-bromosuccinimide ( BS) (16.02 g, 90 mmol) in 100 mL DMF was added dropwise in 30 min. After addition, the mixture was stirred at room temperature for 12 hours, and then poured into water to precipitate. The solid was filtered, and recrystallized from dichloromethane and ethanol to give white solid (yield: 92%). MS (ESI): 516.12 [M+H] ⁺ . Synthesis of 7-([l,l'-biphenyl]-4-yl(4-bromophenyl)amino)-9,9-dimethyl-9H -fluorene-2- carbaldehyde

To a solution of 7-([l, l'-biphenyl]-4-yl(4-bromophenyl)amino)-9,9-dimethyl-9H- fluorene-2-carbaldehyde (25.8 g, 50 mmol) in 100 mL CH ₂ C1 ₂ at 0°C, TiCl ₄ (54.6 mL, 500 mmol) diluted with 100 mL CH ₂ C1 ₂ , were added in 30 minutes. The mixture was stirred for an additional 30 minutes at 0°C. Then, CH ₃ 0CHC1 ₂ (27.0 mL, 300 mmol) in 200 mL of CH ₂ C1 ₂ were added dropwise in 30 minutes. The dark-green solution was stirred for another one hour at 0°C. After completion, water, with crushed ice, was slowly added to quench the reaction. The organic layer was separated, and washed consecutively with saturated sodium bicarbonate solution, brine, and dried over anhydrous sodium sulphate. After filtration, the solvent was removed under vacuum, and the residue was purified through column chromatography to give crude product (yield: 55%). MS (ESI): 544.12

[M+H] ⁺ .

Synthesis of 4-(9H-carbazol-9-yl)benzaldehyde

A mixture of 9H-carbazole (9.53 g, 57 mmol), 4-bromobenzaldehyde (21.1 g, 1 14 mmol), Copper(I) iodide (1.80 g, 9.4 mmol), K ₂ C0 ₃ (1 1.8 g, 86 mmol) in 60 mL dry DMF was heated to 140°C under nitrogen atmosphere for 12 hours. After cooling to room temperature, the inorganic solid was filtered, and the residue was poured into ice water to precipitate. The so-formed solid was collected, and washed by water, ethanol several times, then crystallized from CH ₂ C1 ₂ and ethanol to give light-yellow solid (yield: 95%). MS (ESI): 272.10 [M+H] ⁺ . Synthesis of 4-(3-bromo-9H-carbazol-9-yl)benzaldehyde

To a solution of 4-(9H-carbazol-9-yl)benzaldehyde (26.6 g, 98 mmol) in 100 mL DMF, NBS (17.4 g, 98 mmol) in 100 mL DMF was added dropwise in 30 minutes. After addition, the mixture was stirred at room temperature for 12 hours. The solution was poured into ice water to precipitate the product. After filtration, the solid was collected, and washed by water, ethanol several times, then dried under vacuum, and used for the next step without further purification (yield: 96%). MS (ESI): 350.01 [M+H] ⁺ .

Synthesis of 4-(3-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-9H-carbaz ol-9- yl)benzaldehyde

A mixture of 3-bromo-9-(4-formylphenyl)-9H-carbazole (10.51 g, 30 mmol), 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(l,3,2-dioxaborolane) (9.14 g, 36 mmol, 253),

Pd(dppf) ₂ Cl ₂ (571 mg, 0.75 mmol), CH ₃ COOK (4.41 g, 45 mmol), and 60 mL of dry dioxane was heated at 85°C, under nitrogen atmosphere for 12 hours. After cooling to room temperature, the solvent was removed under vacuum, and then water was added. The mixture was extracted with CH ₂ C1 ₂ . The organic layer was collected, and dried over anhydrous sodium sulphate. After filtration, the filtrate was evaporated to remove solvent, and the residue was purified through column chromatography on silica gel to give white solid (yield: 84%). MS (ESI): 398.16 [M+H] ⁺ . Synthesis of 7-([l,l'-biphenyl]-4-yl(4-(9-(4-formylphenyl)-9H-carbazol-3- yl)phenyl)amino)-9,9-dimethyl-9H-fluorene-2-carbaldehyde

A mixture of 4-(3-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)-9H-carbaz ol-9- yl)benzaldehyde (0.7 g, 1.76 mmol), 7-([l, l'-biphenyl]-4-yl(4-bromophenyl)amino)-9,9- dimethyl-9H-fluorene-2-carbaldehyde (0.8 g, 1.47 mmol), Pd(PPh ₃ ) ₄ (76 mg, 0.064 mmol), 2M K ₂ C0 ₃ (0.8 g, 6 mmol, 3 mL H ₂ 0), 3 mL ethanol and 3 mL of toluene was heated at 90 °C under nitrogen atmosphere for 12 h. After cooling to room temperature, the solvent was removed under vacuum and the residue was dissolved with CH ₂ C1 ₂ . The organic layer was washed with water and then dried over anhydrous sodium sulphate. After filtration, the filtrate was evaporated to remove solvent and the residue was purified through column chromatography on silica gel to give white solid (yield: 85%). MS (ESI): 735.29 [M+H] ⁺ . Synthesis of N-([l,l'-biphenyl]-4-yl)-9,9-dimethyl-6-vinyl-N-(4-(9-(4-vin ylphenyl)-9H- carbazol-3-yl)phenyl)-9H-fluoren-2-amine

To a solution of Ph ₃ PBrMe (1.428 g, 4 mmol) in 10 mL THF at 0 °C, iBuOK (672 mg, 6 mmol) was added under nitrogen atmosphere. After stirring for 30 min, a solution of the dialdehyde compound 7-([l,l'-biphenyl]-4-yl(4-(9-(4-formylphenyl)-9H-carbazol-3- yl)phenyl)amino)-9,9-dimethyl-9H-fluorene-3-carbaldehyde (734 mg, 1 mmol) in 10 mL THF was added to the above mixture. Then, the solution was allowed to stir at room temperature for 12 hours. After quenching with water, the solvent was removed under vacuum, and the residue was dissolved with CH ₂ C1 ₂ . The organic layer was washed with water and then dried over anhydrous sodium sulphate. After filtration, the filtrate was evaporated to remove solvent, and the residue was purified through column chromatography on silica gel to give white solid HTL-SP-3 (yield: 85%). MS (ESI): 731.34 [M+H] ⁺ .

Synthesis of (7-([l,l'-biphenyl]-4-yl(4-(9-(4-(hydroxymethyl)phenyl)-9H-c arbazol-3- yl)phenyl)amino)-9, -dimethyl-9H-fluoren-3-yl)methanol

To a solution of 7-([l, l'-biphenyl]-4-yl(4-(9-(4-formylphenyl)-9H-carbazol-3- yl)phenyl)amino)-9,9-dimethyl-9H-fluorene-3-carbaldehyde (734 mg, 1 mmol) in 10 mL THF and 10 mL ethanol at 40 °C, NaBH ₄ (302 mg, 8 mmol) was added under nitrogen atmosphere. The solution was allowed to stir at room temperature for 2 hours. Then, aqueous hydrochloric acid solution was added until pH 5, and the mixture was kept stirring for 30 minutes. The solvent was removed under vacuum, and the residue was extracted with dichloromethane. The product was then dried under vacuum, and used for the next step, without further purification. MS (ESI): 739.32 [M+H] ⁺ .

Synthesis of N-([l,l'-biphenyl]-4-yl)-9,9-dimethyl-6-(((4-vinylbenzyl)oxy )methyl)-N-(4- (9-(4-(((4-vinylbenzyl)oxy)methyl)phenyl)-9H-carbazol-3-yl)p henyl)-9H-fluoren-2- amine

To a solution of (7-([l,l'-biphenyl]-4-yl(4-(9-(4-(hydroxymethyl)phenyl)-9H- carbazol-3-yl)phenyl)amino)-9,9-dimethyl-9H-fluoren-3-yl)met hanol (3.69 g, 5 mmol), in 50 mL dry DMF, was added NaH (432 mg, 18 mmol), then the mixture was stirred at room temperature for 1 hour. Then, 4-vinylbenzyl chloride (2.11 mL, 2.29 g, 15 mmol) was added to above solution via syringe. The mixture was heated to 60°C for 24 hours. After quenched with water, the mixture was poured into water to remove DMF. The residue was filtered, and the resulting solid was dissolved with dichloromethane, which was then washed with water. The solvent was removed under vacuum, and the residue was extracted with dichloromethane. The product was then obtained by column chromatography on silica gel to give light-yellow solid HTL-SP-4(yield: 75%). MS (ESI): 971.45 [M+H] ⁺ .

Film Preparation

1. HTL-SP-8 + HTL-SP-3 Solution Preparation

HTL-SP-8 (0.0369 g; MW = 915.149 Da) and HTL-SP-3 (0.0277 g; MW=730.955 Da) were dissolved in anisole (3.1444 g), at room temperature, to make a "2 wt% HTL-SP-8 + HTL-SP-3" solution (HTL-SP-8 : HTL-SP-3= approximately a 1 : 1 molar ratio). Once the HTL-S-8 and HTL-SP-3 were completely dissolve in anisole, the solution was filter through a "0.2 μπι PTFE membrane," prior to depositing the solution onto the Si wafer (see below). The silicon wafers were available from Virginia Semiconductor, Inc. (one inch, Single-Side-Polished (SSP) undoped Si wafers with 0.5 mm thickness).

2. HTL-SP-8 + HTL-SP-3 Thin Film on Si Wafer via Spin Coating and Thermal Cross- Linking

The Si wafer was "UV-ozone pre-treated" for one minute. Next, 4-6 drops of the filtered "HTL-SP-8 and HTL-SP-3 solution" was deposited onto the Si wafer, and coated wafer was spin coated to form a thin film of the "HTL-SP-8 + HTL-SP-3 solution" on Si wafer using two spinning steps: 1) 500 rpm for five seconds, and 2) 1500 rpm for 30 seconds. The spin-coated wafer was pre-baked at 100°C, for one minute, under a nitrogen atmosphere (N2 box) to remove most of the residual anisole.

Three or two film coated wafers were then heated, under nitrogen atmosphere, at 190, 220, 235, or 250°C, for 5, 10, 20, 30, 40, 50 or 60 minutes, under nitrogen atmosphere (N2 purge box), to form one data (temp./time) set. See Table 1 below.

3. HTL-SP-8 + HTL-SP-3 Thin Film Strip Test

The "Initial" thickness of "HTL-SP-8 + HTL-SP-3" each coated film of each data set were measured, and the average ± standard deviation was recorded (see Table 1). An anisole was used to strip the "HTL-SP-8 + HTL-SP-3 film" - a 90 second puddle time was used in this analysis. Each "HTL-SP-8 + HTL-SP-3 film" coated wafer was immediately spin dried at 3500 rpm for 30 seconds, and the "stripped" film thickness of each film of each data set was immediately measured, and the average ± standard deviation was recorded (see Table 1).

Each HTL-SP-8 + HTL-SP-3 film of each data set was post-baked at 100°C for one minute, under nitrogen atmosphere (N2 purge box), to bake off excess anisole. The "Final" film thickness was measured, and the average ± standard deviation was recorded (see Table 1). Strip data is shown in Table 1. See also Figure 1.

Table 1 : Strip Test Summary of "HTL-SP-8 and HTL-SP-3" Films

Note: "- Strip" = "Stripped" - "Initial"; "-PSB" = "Final" - "Stripped"; "Total" = "-Strip" + "-PSB" HTL-SP-3 : N-([l, l'-biphenyl]-4-yl)-9,9-dimethyl-6-vinyl-N-(4-(9-(4-vinylphen yl)-9H-carbazol-3- yl)phenyl)-9H-fluoren-2 -amine.

HTL-SP-8: N-([l,l'-biphenyl]-4-yl)-N-(4-(9-(3,5-bis(bicyclo[4.2.0]octa -l(6),2,4-trien-7-yloxy)phenyl)-9H- carbazol-3-yl)phenyl)-9,9-dimethyl-9H-fluoren-2-amine.

HTL-SP-8 + HTL-SP-3 Blend Preparation and DSC Study

HTL-SP-8 ( 5.5 mg; MW=915.149 Da) and 4.4 mg HTL-SP-3 (4.4 mg; MW=730.955 Da) were dissolved in 500 mg THF, at room temperature, to form a "2 wt% HTL-SP-8 + HTL-SP-3" solution (HTL-SP-8 : HTL-Sp-3 = approximately a 1 : 1 molar ratio). After the HTL-S-8 and HTL-SP-3 were completely dissolved in the THF, the solution was "air purge," to remove most THF, followed by vacuum dry, at room temperature, for two hours, to form a dried film for DSC analysis. DSC results are shown in Table 2. See also Figures 2-4.

Table 2

HTL-SP-3 : N-([l, l'-biphenyl]-4-yl)-9,9-dimethyl-6-vinyl-N-(4-(9-(4-vinylphen yl)-9H-carbazol-3- yl)phenyl)-9H-fluoren-2-amine.

HTL-SP-8: N-([lJ'-biphenyl]-4-yl)-N-(4-(9-(3,5-bis(bicyclo[4.2.0]octa- l(6),2,4-trien-7-yloxy)phenyl)-9H- carbazol-3-yl)phenyl)-9,9-dimethyl-9H-fluoren-2-amine.

Figure 2 depicts the DSC profile of HTL-SP-8. The onset for the first exothermic event occurred at about 117°C and ended at about 200°C, whereas the second exothermic event began at about 200°C and ended at about 250°C. These exothermic events occur when new C-C bonds are formed, as a result of the Diels-Alder cycloaddition reaction.

Figure 3 depicts the DSC profile of HTL-SP-3. The onset for the first exothermic event occurred at about 167°C and ended at >250°C. These exothermic events occur when new C-C bonds are formed, as a result of the thermal styrene polymerization

Figure 4 depicts the DSC profile of HTL-SP-8 and HTL-SP-3. The onset for the first exothermic event occurred at about 166°C and ended at about 240°C (or 250°C?). These exothermic events occur when new C-C bonds are formed, as a result of the Diels- Alder [4+2] cycloaddition reaction.

Figure 5 depicts the MALDI-TOF profile of the film produced by heating HTL-SP-3 and HTL-SP-8 at 190°C. The product peaks are indicative of the product mass obtained from a [4+2] Diels-Alder cycloaddition reaction. Figure 6 depicts an expanded MALDI- TOF profile of Figure 5.

As shown in the study above, it has been discovered that the inventive compositions (using at least one attachment point on an hole transport layer molecules), the energy required for rearrangement during oxidation, and more efficiently chain stack the molecular cores into close proximity to each other, is minimized. This inventive approach enhances the transport of holes in the HTL layer via thru-space interactions, which is in contrast to prior art in this field. These properties result in increased device efficiency, device lifetime and lower device driving voltage. Furthermore, the chemistry described in this invention can also satisfy temperature and time considerations, and thus provide improved process conditions for film configurations for electronic devices.