[DESCRIPTION]

[Invention Title]

ORGANIC TRANSISTOR AND METHOD FOR FABRICATING THE SAME

[Technical Field]

The present invention relates to an organic transistor and a method

of producing the same. This application claims priority from Korean

Patent Application No.10-2007-0014882 filed on February 13, 2007 in the

Korean Intellectual Property Office, the disclosure of which is

incorporated herein by reference in its entirety.

[Background Art]

A thin film type field-effect transistor (FET) is a basic structure

in a microelectronic field. The FET includes three electrodes, that is,

a source electrode, a drain electrode, and a gate electrode, an insulating

layer, and a semiconductor layer. In the case of when the above

semiconductor layer is a conductive channel between the two above

electrodes, that is, the source electrode and the drain electrode, the

FET acts as a capacitor. In the above channel, the concentration of the

charge carrier is controlled by using voltage that is applied through the

gate electrode. As a result , a flow of electric charges between the source

electrode and the drain electrode may be controlled by voltage that is

applied through the above gate electrode.

Recently, a concern has been grown rapidly about FETs using an

organic semiconductor material. In the case of when the organic

semiconductor material is used, electronic devices may be produced by

using a printing process such as screen-printing, ink-jet printing, or

micro-contact printing. In addition, in the case of when the above

material is used, the process may be performed at a very low temperature

of the substrate in a state where a vacuum is not required as compared

to the case of when a known inorganic semiconductor material is used.

Therefore, the electronic device using the organic semiconductor material

including FETs may be produced under a very soft production condition at

the low cost as compared to the case of when the inorganic semiconductor

material is used.

Studies have been conducted to use organic materials such as small

molecules, polymers, and oligomers as an organic semiconductor material

in FETs since the 1980s. With respect to results of studies in the

above-mentioned field, in views of the charge carrier mobility in FETs,

performance of the organic FET is increased from 10 ^~5 cm ² /Vs to 1 cm ² /Vs

(J. M. Shaw, P. F. Seidler, IBMJ. Res. & Dev. , Vol.45, 3 (2001)). The

performance of the organic transistor is as good as that of a current

amorphous silicon transistor. Thus, the organic transistor may be

applied to E-papers, smart cards, or display devices.

In order to improve the performance of the organic FET, efforts have

been made to mix conductive particles and semiconductor organics with each

other. Scientists of AIST in Japan announced test results that when P3HT

and Ag nanoparticles were mixed with each other to form a semiconductor

layer, an off current was reduced, in other words, the Ag nanoparticles

acted as an antioxidant. However, in the above results, since the

conductive particles are not present in the conductive channel but between

alkyl groups of P3HT, the charge mobility cannot be improved.

[Disclosure]

[Technical Problem]

The present inventors have found that in the case of when a material

having conductive particles and an organic semiconductor polymer

chemically bonded to each other is used as a material of an organic

semiconductor layer, an organic transistor can be produced by using a wet

process and performance of the produced organic transistor can be

improved.

Accordingly, it is an object of the present invention to provide

an organic transistor that includes an organic semiconductor layer

containing a material having conductive particles and an organic

semiconductor polymer chemically bonded to each other and a method of

producing the same.

[Technical Solution]

In order to accomplish the above object, the present invention

provides an organic transistor that includes an organic semiconductor

layer containing a material having conductive particles and an organic

semiconductor polymer chemically bonded to each other.

Furthermore, the present invention provides a method of producing

anorganic transistor, which includes layer ing an insulating layer, agate

electrode, a source electrode, a drain electrode, and an organic

semiconductor layer on a substrate. The organic semiconductor layer is

formed by using a material having conductive particles and an organic

semiconductor polymer chemically bonded to each other.

[Advantageous Effects]

An organic transistor according to the present invention includes

an organic semiconductor layer that contains a material having conductive

particles and an organic semiconductor polymer chemically bonded to each

other. Therefore, it is possible to provide the organic transistor that

has excel lent performance and is capable of being easi Iy produced by using

a wet process.

[Description of Drawings]

FIG. 1 illustrates a bottom contact type organic thin film

transistor device that includes a substrate 8, an insulating layer 9, a

gate electrode 10, a source electrode 11, a drain electrode 12, and an

organic semiconductor layer 13;

FIGS.2 and 3 are pictures of materials that are produced in Examples

2 and 3 by using a transmission microscope; and

FIGS.4 and 5 are characteristic curves of an organic transistor

that is produced in Experimental Example 1.

[Best Mode]

Hereinafter, the present invention will be described in detail.

An organic transistor according to the present invention is

characterized in that the organic transistor includes an organic

semiconductor layer containing a material having conductive particles and

an organic semiconductor polymer chemically bonded to each other.

In the present invention, examples of the conductive particles

include noble metal particles, for example, Au, Ag, and Pt particles, or

metal oxide particles, for example, ITO, IZO, and ZnO particles. It is

preferable that the particle size of the above conductive particle be in

the range of 5 nm to 1 μm. If the particle has the particle size of less

than 5 nm, it is difficult to synthesize the particles and to control the

particle diameter of the particles. If the particle has the particle size

of more than 1 JM, a difference between devices may be increased since

it is difficult to statistically control the number of particles in the

channel of the organic transistor.

In the present invention, the above organic semiconductor polymer

may be represented by the following Formula 1.

[Formula 1]

I ^λ D 2

In the above Formula, X is a conductive polymer, and Bl and B2 are

end capping functional groups of X and are capable of being chemically

bonded to the conductive particles.

According to the present invention, Bl and B2 that are the

functional groups provided at X of the above organic semiconductor polymer

may be chemically bonded to the conductive particles such as metals or

metal oxides to prepare a material that includes the organic semiconductor

polymer and the conductive particles chemically bonded to each other and

can be used in a solution process, and the material may be used to produce

an organic transistor having excellent performance. Specifically, the

conductive polymer and the conductive particles maybe bonded to each other

by chemical bonding using Bl and B2 that are the end capping functional

groups to minimize contact resistance which may occur during movement of

electric charges as compared to the case of when the two materials are

simply mixed with each other. In addition, the organic semiconductor

polymer maybe used to ensure the solubi lity of the above material required

in the solution process.

The organic semiconductor polymer of the above Formula 1 may be

reacted with the conductive particles such as metals or metal oxides to

prepare a material having the above conductive particles and the organic

semiconductor polymer chemically bonded to each other. In addition, the

metal or metal oxide particle precursor may be mixed with the organic

semiconductor polymer that is represented by Formula 1 to prepare a

material having the above conductive particles and the organic

semiconductor polymer chemically bonded to each other. In connection

with this, the metal or metal oxide particle precursor means an ionically

bonded compound having metal ions, and examples of the metal or metal oxide

particle precursor may include HAuCl ₄ , AgNOs, silver citrate and the like.

For example, in order to prepare the material having Au or Ag particles

chemically bonded thereto, among the compounds that are represented by

Formula 1, the material having -SH as Bl and B2 that are the functional

groups is used, the Au or Ag precursor is mixed with the material, and

a reducing agent is used to prepare a material having metal particles and

an organic semiconductor polymer bonded to each other. During the

preparation process, a solvent may be used. In connection with this, a

solvent that is capable of desirably dissolving the organic semiconductor

polymer may be used as the above solvent, and it is preferable to use a

solvent having chlorine such as chlorobenzene and chloroform.

It is preferable that the above organic semiconductor polymer and

the conductive particles be contained in the organic semiconductor layer

of the organic transistor according to the present invention at a weight

ratio of 10:1 to 1:10,000. More preferably, the organic semiconductor

polymer and the conductive particles are contained at a weight ratio of

10:1 to 1:10. If the weight ratio is less than 10:1, since the amount

of the conductive particles is reduced, the effect of the present invention

is reduced. If the weight ratio is more than 1:10,000, it is difficult

to perform the solution process due to the aggregation between the

conductive particles.

In the present invention, it is preferable that the organic

semiconductor layer including the material having the above conductive

particles and the organic semiconductor polymer chemically bonded to each

other have a thickness in the range of 10 nm to 1 μm. If the thickness

is less than 10 nm, the charge conductive layer formed to have a thickness

of 5 nm or less is easily degraded due to moisture or oxygen. If the

thickness is more than 1 μm, there is a problem in that an on/off ratio

is reduced.

In the present invention, X which is the above conductive polymer

is not limited, but a polymer that includes thiophene, aniline, pyrrole

or the like may be used. It is preferable to use the conductive polymer

that is capable of preparing a solution having a concentration of 0.1 wt%

or more in respects to the solvent that is used to form the organic

semiconductor layer of the organic transistor, and it is more preferable

to use the conductive polymer that is capable of preparing a solution

having a concentration of 1 wt% or more. Any solvent that is known in

the art may be used as the solvent that is used to form the above organic

semiconductor layer. For example, as described above, the solvent that

contains chlorine may be used, but the solvent of the present invention

is not limited thereto.

It is preferable that the above conductive polymer have a molecular

weight of 3,000 or more. More preferably, the molecular weight is 5,000

or more. In the case of when the conductive polymer having the molecular

weight of 3,000 or more is used, it is possible to obtain the desirable

solubility in respects to the solvent. Thus, it is easy to perform the

process.

For example, Bl and B2 may be groups containing -SH in the case of

when the conductive particles are noble metal particles such as Au or Ag

particles, or may be groups containing a phosphate group in the case of

when the conductive particles are metal oxide particles, for example, ITO,

IZO, and ZnO particles.

In the above Formula 1, X may include a structural unit that is

represented by the following Formula 2.

[Formula 2]

In the above Formula 2, x, y, and z are a ratio of the structural

units, x is a real number with 0<x≤l, y is a real number with 0≤y<l,

z is a real number with 0<z<l, and x+y+z = 1,

n is an integer in the range of 5 to 1,000, and more preferably an

integer in the range of 10 to 1,000,

Ar and Ar' are the same as or different from each other, and are

independently a bivalent cyclic or non-cyclic hydrocarbon group having

a conjugated structure, or a bivalent heterocyclic group having a

conjugated structure,

A and B are the same as or different from each other, and are

independently a bivalent cyclic or non-cyclic hydrocarbon group having

a conjugated structure, a bivalent heterocyclic group having a conjugated

structure, or an acyclic group as follows:

In the above Formulae, R' and R' ' are the same as or different from

each other, and may be independently a hydrogen atom; a halogen atom; a

linear, branched, or cyclic alkyl group; a linear, branched, or cyclic

alkoxy group; a thioalkoxy group; a nitri Ie group; anitrogroup! an amino

group; a substituted or unsubstituted aryl group, or a substituted or

unsubstituted heteroaryl group, and the dotted line is a portion linked

to a main chain of Formula 2.

In the above Formula 2, Ar and Ar' may be an arylene group or

heteroarylene group having a conjugated structure.

In the above Formula 2, it is preferable that A or B be an aromatic

group (Ar ").

As an example of A or B, the above aromatic group (Ar' ' ) is an arylene

group or a heteroarylene group, and preferably a group that is represented

by the following Formulae.

In the above Formulae, X is an 0, S, Se, NR ³ , SiR ³ R ⁴ , or CR ³ R ⁴ group,

and R ³ and R ⁴ are the same as or different from each other , are independently

a hydrogen atom; a linear, branched, or cyclic alkyl group; or an aryl

group, and may be bonded to each other to form a ring,

R ¹ and R ² are the same as or different from each other, and are

independently a hydrogen atom, a hydroxy1 group, a halogen atom, anitrile

group, a nitro group, an ester group, an ether group, an amino group, an

imide group, a silane group, a thioester group, a substituted or

unsubstituted and linear, branched, or cyclic alkyl group having 1 to 20

carbon atoms, a substituted or unsubstituted and linear, branched, or

cyclic alkoxy group having 1 to 20 carbon atoms, a substituted or

unsubstituted and linear, branched, or cyclic thioalkoxy group having 1

to 20 carbon atoms, a substituted or unsubstituted aryl group, or a

substituted or unsubstituted heteroaryl group,

two or more carbon atoms which are contained in R ¹ and/or R ² and

are not adjacent to each other may be linked by 0, S, NH, -NR ⁰ -, SiR ⁰ R ⁰⁰ -,

-00-,-COO-, -0C0-, -0C00-, -S-CO-, -CO-S-, -CH=CH-, a substituted or

unsubstituted aryl group, or a substituted or unsubstituted heteroaryl

group, R ⁰ and R ⁰⁰ are the same as or different from each other, and are

independently hydrogen, an aryl group, or an alkyl group having 1 to 12

carbon atoms, and

R ¹ and R ² may be bonded to each other to form a ring.

In the above Formulae, in the case of when R ¹ or R ² is a substituted

alkyl, alkoxy, or thioalkoxy group having 1 to 20 carbon atoms, the

hydrogen atom bonded thereto can be substituted with at least one

substituent group of fluorine, chlorine, bromine, iodine, and nitrile.

In the above Formulae, in the case of when R ¹ or R ² is a substituted

aryl or heteroaryl group, it can be substituted with at least one

substituent group of a halogen group, a nitrile group, a hydroxyl group,

an alkyl group, an alkoxy group, a vinyl group, an acetylene group, a

thioalkoxy group, a nitro group, an amide group, an imide group, an ester

group, an ether group, an amino group, and a si lane group.

Examples of Ar, Ar ¹ and Ar' ' in the above Formulae will be listed

as follows. However, these examples are for the illustrative purpose only,

and the invention is not intended to be limited thereto.

In the above Formulae, the position, at which no substituent is

presented, may be a hydrogen atom, and may be substituted with at least

one of a halogen group, an alkyl group, an alkoxy group, a thioalkoxy group,

an aryl group, an amino group, a nitrile group, a nitro group, an ester

group, an ether group, an amide group, an amide group, an imide group,

a hetero group, a vinyl group, an acetylene group, a si lane group, or the

like, R, R ¹ and R' ' are the same as or different from each other and are

independently a hydrogen atom, an alkyl group, or an aryl group, and m

is an integer in the range of 1 to 10 and more preferably an integer in

the range of 1 to 6.

The compound that is represented by the above Formula 2 may contain

a structural unit of the following Formula 3.

[Formula 3]

In the above Formula 3,

R ⁵ to R ⁸ are the same as or different from each other, and are

independently a hydrogen atom, a hydroxyl group, a halogen atom, a nitri Ie

group, a nitro group, an ester group, an ether group, an amino group, an

imide group, a si lane group, a thioester group, a substituted or

unsubstituted and linear, branched, or cyclic alkyl group having 1 to 20

carbon atoms, a substituted or unsubstituted and linear, branched, or

cyclic alkoxy group having 1 to 20 carbon atoms, a substituted or

unsubstituted and linear, branched, or cyclic thioalkoxy group having 1

to 20 carbon atoms, a substituted or unsubstituted aryl group, or a

substituted or unsubstituted heteroaryl group,

two or more carbon atoms which are contained in R ⁵ to R ⁸ and are

not adjacent to each other may be linked by 0, S, NH, -NR ⁰ -, SiR ⁰ R ⁰⁰ -,

-CO-,-C00-, -0C0-, -0C00-, -S-CO-, -CO-S-, -CH=CH-, a substituted or

unsubstituted aryl group, or a substituted or unsubstituted heteroaryl

group, R ⁰ and R ⁰⁰ are the same as or different from each other, and are

independently hydrogen, an aryl group, or an alkyl group having 1 to 12

carbon atoms,

R ⁵ and R ⁶ or R ⁷ and R ⁸ may be bonded to each other to form a ring,

and

n, x, y, z, A, and B are as defined by Formula 2.

In the above Formula 3, in the case of when at least one of R ⁵ to

R ⁸ is a substituted alkyl, alkoxy, or thioalkoxy group, the hydrogen atom

substituted thereto can be substituted with at least one group of fluorine,

chlorine, bromine, iodine, and nitrile.

In the above Formula 3, in the case of when at least one of R° to

R ⁸ is a substituted aryl or heteroaryl group, it can be substituted with

at least one of a halogen group, a nitrile group, a hydroxyl group, an

alkyl group, an alkoxy group, a vinyl group, an acetylene group, a

thioalkoxy group, a nitro group, an amide group, an imide group, an ester

group, an ether group, an amino group, and a si lane group.

In the preferred embodiment of the present invention, specific

examples of the above Formula 2 are represented by the following Formulae.

However, these examples are for the illustrative purpose only, and the

invention is not intended to be limited thereto.

Formul a R-I Formula R-2

Formul a S-I Formul a S-2

Formula S-3 Formula S-4

Formula S-5 Formula S-6

Formula S-7 Formula S-8

Formula S-9 Formula S-IO

Formula R-3

Formula S- 11

Formula S-12

Formula S- 13

Formula S- 14

Formul a R-4

Formula S- 15

Formula S-16

Formula S-17

Formula S-18

Formula S- 19

Formula S-20

Formula S-21

Formula S-22

Formula S-23

Formula S-24

Formul a S-25 Formul a S-26

Formula S~27 Formula S~28

Formula S-29

Formula S-30

Formula S-31

Formula R-5

Formula S-32

Formula S-33

Formula S-34

Formula S-35

Formula S-36

Formula S-37

Formula S-38

Formula S-39

Formula S-40

Formula S-41

wherein R to R' contained in the above Formulae R-I to R-5 and

S-I to S-41 are the same as or different from each other, and are

independently a hydrogen atom, a hydroxyl group, a halogen atom, a nitri Ie

group, a nitro group, an ester group, an ether group, an amino group, an

imide group, a si lane group, a thioester group, a substituted or

unsubstituted and linear, branched, or cyclic alkyl group having 1 to 20

carbon atoms, a substituted or unsubstituted and linear, branched, or

cyclic alkoxy group having 1 to 20 carbon atoms, a substituted or

unsubstituted and linear, branched, or cyclic thioalkoxy group having 1

to 20 carbon atoms, a substituted or unsubstituted aryl group, or a

substituted or unsubstituted heteroaryl group. Theymay be bonded to each

other to form a ring, and n, x, and y are as defined by Formula 2.

In the organic transistor according to the present invention, the

above organic semiconductor layer may be produced by preparing the

solution of the material having the conductive particles and the organic

semiconductor polymer chemically bonded to each other and performing a

printing process such as screen printing, inkjet printing, or microcontact

printing.

The organic transistor according to the present invention may be

produced by using a method and a material that are known in the art , except

that the organic semiconductor layer is formed by using the

above-mentioned material.

For example, the organic transistor according to the present

invention can be prepared by layering an insulating layer 9, a gate

electrode 10, a source electrode 11, a drain electrode 12, and an organic

semiconductor layer 13 on a substrate 8 according to a PVD (physical vapor

deposition) process such as sputtering or e-beam evaporation or a solution

coating process, but the scope of the present invention is not limited

thereto. In connection with this, the above organic semiconductor layer

maybe formed to have a single layer structure or a multi layered structure.

[Mode for Invention]

Hereinafter, the present invention will be described in detail with

reference to Examples. Examples are provided only for the purpose of

illustrating the present invention, and accordingly it is not intended

that the present invention is limited thereto.

EXAMPLE

PREPARATION EXAMPLE

Synthesis of 3-dodecylthiophene

Dried ethyl ether (40 ml) was added to activated magnesium (1.22

g; 50 mmol), and 1-bromododecane (12.46 g; 50 mmol) was added thereto to

prepare a Grignard reagent. Then, Ni(dppρ)Cl2 (33 mg) was added thereto,

and 3-bromothiophene (8 g; 49 mmol) dissolved in 10 ml of ether was slowly

added dropwise. The reaction solution was refluxed for one day, and then

a mixture of 2N HCl/ice (50 ml) was added to terminate the reaction. The

resultant was extracted by using ethyl ether, and the solvent was disti lied

off under reduced pressure. The residue was dissolved in DMF (50 ml) and

filtered to remove remaining paraffin. The filtrate was concentrated,

and then the residue was distilled off under vacuum to obtain a colorless

liquid of 3-dodecylthiophene (10.5 g; 85%).

Synthesis of 2-bromo-3-dodecylthiophene

A solution of N-bromosuccinimide (NBS) (48 g; 0.27 mol) dissolved

in DMF (160 ml) was slowly added to a solution of 3-dodecylthiophene (68

g; 0.27 mol) dissolved in DMF (110 ml). After the reaction solution was

stirred for one day, 750 ml of water was added thereto. An organic

material was extracted by using ethyl ether (3 x 300 ml), and washed with

brine and water, and then the residual moisture was removed over anhydrous

magnesium sulfate. After removing the solvent , the residue was disti lied

off under reduced pressure at 125 ^° C/~5 niniHg to obtain a product (84.85

g, yield of 94%).

Synthesis of 3-dodecylthiophene-2-carboaldehyde

After magnesium (0.63 g; 25.8 mmol) and anhydrous THF (25 ml) were

put into a flask, 2-bromo-3-dodecylthiophene (7.78 g! 23.5 mmol) was

slowly added thereto. After starting Grignard reaction, the solution was

refluxed until magnesium was almost removed. The purified DMF (3.65 g;

~4 ml; 50 mmol) was slowly added dropwise to the reaction solution. The

reaction solution was refluxed for one day, and cooled to 0 ^° C , and 5% HCl

(100 ml) was added thereto to terminate the reaction. An organic layer

was extracted by using ethyl ether, and the obtained organic layer was

washed sequentially with NaHCOs, a saturated NaCl aqueous solution, and

water. The residual moisture was removed over anhydrous magnesium

sulfate. After removing the solvent, the residue was subjected to a

column separation process by using silica gel (ethyl acetate/hexane = 1/9)

to obtain 3-dodecylthiophene-2-carboaldehyde (3.6 g; 55%).

Synthesis of 5,5'-bis(3-dodecyl-2-thienyl)-thiazolothiazole

3-dodecylthiophene-2 ^~ carboaldehyde (3.9 g; 14 mmol) and

dithiooxamide (0.8 g; 6.6 mmol) were put into a flask, heated at 180"C

for one hour, and then cooled to room temperature. Chloroform was added

thereto, and stirring and filtering were performed. The obtained

material was recrystallized by using hexane three times, and further

recrystallized by using acetone/ethyl acetate to obtain a product (1.5

g; 35%) having a purity of 99.57% (the purity measured by HPLC). The

melting point of the material was 60 ^° C .

Synthesis of

2,2'-bis(bromo)-5,5'-bis(3-dodecyl-2-thienyl)-thiazolothi azole

After shielding light , a NBS (0.28 g, 1.57 mmol) solution dissolved

in a mixture of chloroform/acet ic acid (20/10 ml ) was slowly added dropwise

to 5,5'-bis(3-dodecyl-2-thienyl)-thiazolothiazole (0.5 g, 0.78 mmol)

dissolved in a CHCh/AcOH mixture (20/10 ml ) at 0 ^° C . The reaction solution

was stirred at the same temperature for 2 hours, and then stirred at room

temperature for one day. The reaction solution was washed with water,

and treated with anhydrous magnesium sulfate. The resultant was

recrystallized by using an acetone/hexane (líl) solvent to obtain

2,2'-bis(bromo)-5,5'-bis(3-dodecyl-2-thienyl)-thiazolothi azole (0.6 g,

96% of yield).

Synthesis of 5,5'-bis(3-dodecyl)-2,2'-dithiophene

Under nitrogen atmosphere, 2-bromo-3-dodecylthiophene (6.Og, 18

mmol) was added dropwise to 35 ml of a THF solution, in which magnesium

(0.22 g, 9 mmol) was dispersed. After preparing a Grignard reagent, the

reaction solution was cooled to room temperature.

Pd(dppp)Cl2((l,3-bis[diphenylphosphino]propane)dichloroni ckel (II)

bisdiphenylphosphospinoethanedichloronickel) (0.2 g, 0.4 mmol) and 15ml

of anhydrous THF were added thereto, and the reflux was performed for 24

hours. After terminating the reaction with a 5% HCl aqueous solution,

the resultant was diluted with ethyl ether, and washed with water, and

moisture was removed over anhydrous magnesium sulfate. After removing

the solvent, the residue was subjected to a column purification process

with n-hexane on silica gel to obtain

5,5'-bis(3-dodecyl)-2,2'-dithiophene (2.5 g; 54% of yield).

Synthesis of

2,2'-bis(trimethylstenyl)5,5'-bis(3-dodecyl-2-thienyl)

5,5'-bis(3-dodecyl)-2,2'-dithiophene (14.3 g; 28.4mmol) and TMEDA

(13 ml; 85.3 mmol) were dissolved in 350 ml of dried hexane, and the 2.5

M n-BuLi (2.5 M in hexane) solution (30 ml; 71 mmol) was slowly added

thereto dropwise at -78 ^° C. The temperature of the reaction solution was

increased to 0 ^° C , the solution was stirred for one hour, and the cooling

was performed so that the temperature was reduced to -78°C . Trimethyltin

chloride (17 g; 85.3 mmol) that was diluted in 30 ml of hexane was added

thereto, the temperature of the reaction solution was increased to normal

temperature, and the stirring was performed for a day. The reaction

solution was diluted by using hexane, and washed with water, and moisture

was removed by using anhydrous magnesium sulfate. After pressure was

reduced to remove the solvent, the residue (-24 g) was recrystallized by

using ethanol/acetone (350 ml / 100 ml) and additionally recrystallized

by using ethanol (600 ml) to obtain a pure product (21.4 g; yield: 91%).

EXAMPLE 1

Synthesis of thiophenol-end capped

poly(tetra(dodecylthiophene)thiazolothiazole) (polymer 1)

The magnet i c bar ,

2,2'-bis(5-bromo-3-dodecylthio-thienyl)thiazolothiazole (0.80089 g; 1

mmol), 2,2'-bis(trimethylstenyl)-5,5 ^l -bis(3-dodecyl-2-thienyl)

(0.92791 g; 1.12 mmol), tris(dibenzylideneacetone) dipalladium(4.6 mg;

0.5 mol%), tri(o-tolyl)phosphine (12.1 g", 4.5 mol%), and

o-dichlorobenzene (5 ml) were put into a glass for microwave reactors,

the reaction was performed at 180 ^° C for lOinin, and the resultant was cooled

to 50 ^° C. 4-bromothiophenol (0.2 g; 1 mmol) that was dissolved in 0.4 ml

of o-dichlorobenzene was added thereto, and the reaction solution was

reacted at 180 ^° C for 120 sec. After the reaction, the resulting solution

was cooled to 50°C, and added to a solvent mixture of methanol and a 37%

hydrochloric acid (10: 1) to obtain a product . After the drying in a vacuum,

the polymer and N,N-diethylphenylazothioformamide (150 mg) were dissolved

in chloroform (120 ml), and stirred in a nitrogen atmosphere for 2 hours

to remove metal . After pressure was reduced to obtain a solid, a Soxhlet

purification process was performed by sequentially using methanol,

acetone, hexane, and methylene chloride to obtain a product.

EXAMPLE 2

Synthesis of poly(tetra(dodecylthiophene)thiazolothiazole)-gold

nanoparticles (polymer : Au = 2:1)

The solution of HAuCU (50 mg) that was dissolved in chloroform (2

ml) and the solution of the polymer 1 (100 mg of the polymer 1 was dissolved

in 20 ml of chloroform) were mixed with each other in the dry box. The

reaction solution was stirred at normal temperature for one hour, and the

5 lithium triethyl borohydride (1.0 M in THF) solution was added thereto

until the gas was not generated any more. After the reaction solution

was strongly stirred in an argon atmosphere at normal temperature for an

additional period of time of 2 hours, the reaction solution was

precipitated in ethanol. The obtained solid was subjected to a Sohxlet

10 process by using acetone to perform the purification, and then subjected

to vacuum drying to obtain a dark red product.

EXAMPLE 3

Synthesis of poly(tetra(dodecylthiophene)thiazolothiazole)-gold

nanoparticles (polymer : Au = 10:1)

The solution of HAuCl ₄ (10 mg) that was dissolved in chloroform (2

ml) and the solution of the polymer 1 (100 mg of the polymer 1 was dissolved

in 20 ml of chloroform) were mixed with each other in the dry box. The

reaction solution was stirred at normal temperature for one hour, and the

lithium triethyl borohydride (1.0 M in THF) solution was added thereto

until the gas was not generated any more. After the reaction solution

was strongly stirred in an argon atmosphere at normal temperature for an

additional period of time of 2 hours, the reaction solution was

precipitated in ethanol. The obtained solid was subjected to a Sohxlet

process by using acetone to perform the purification, and then subjected

to vacuum drying to obtain a dark red product (97 mg; yield of 94%).

The materials of the above Examples 2 and 3 were observed by using

a transmission electron microscope (TEM). In result, as shown in FIGS.

2 and 3, the Au nanoparticle had the size of about 10 run. In addition,

it could be seen that the number and the size of the particles were

controlled as the amount of the Au precursor was reduced.

EXPERIMENTAL EXAMPLE 1

The organic transistor that had the structure shown in FIG. 1 was

produced. The n-dopped silicon wafer was used as the substrate and the

gate electrode, and silicon oxide (300 run) that was grown and formed by

using heat treatment was used as the gate insulating layer thereon. The

source electrode and the drain electrode that were made of gold were formed

on the gate insulating layer by using an e-beam. The substrate thus

prepared was treated by using HMDS (hexamethyldisi lazane) . The solut ion

of the material that was prepared in Example 3 and dissolved in

chlorobenzene in an amount of 0.1 w/v% was applied on the substrate on

which the source electrode and the drain electrode were formed by using

spin coating at a rate of 500 rpm for 30 sec, subjected to preanealing

at 70°C, and subjected to heat treatment at 100 ^° C for 1 hour to form an

organic semiconductor layer. In connection with this, the width and the

length of the channel of the organic transistor were 300 μm and 10 μm,

respectively.

The results of the above transistor are shown in FIGS.4 and 5. In

result, the charge mobility of the transistor was 3.5 X 10 ^"4 cm ² /V.s and

the on/off ratio thereof was 10 ³ in a saturation region.