JP6551163B2 - Heteroacene derivative, organic semiconductor layer, and organic thin film transistor - Google Patents

Description

  The present invention relates to a novel heteroacene derivative which can be developed into an electronic material such as an organic semiconductor material, an organic semiconductor layer and an organic thin film transistor using the same, and in particular, it is easily manufactured because of excellent solubility in a solvent. The present invention relates to a novel heteroacene derivative which enables preparation of an organic semiconductor solution for a film, an organic semiconductor layer and an organic thin film transistor using the same.

  Organic semiconductor devices typified by organic thin film transistors have recently been attracting attention because they have features not found in inorganic semiconductor devices such as energy saving, low cost and flexibility. This organic semiconductor device is composed of several kinds of materials such as an organic semiconductor layer, a substrate, an insulating layer, an electrode, etc. Among them, the organic semiconductor layer responsible for carrier movement of charge has a central role of the device. And, since the organic semiconductor device performance depends on the carrier mobility of the organic semiconductor material that constitutes this organic semiconductor layer, the appearance of an organic semiconductor material that gives high carrier mobility is desired.

  As a method of producing an organic semiconductor layer, generally known methods such as a vacuum evaporation method implemented by evaporating an organic material under high temperature vacuum, a coating method of dissolving the organic material in an appropriate solvent and coating the solution It is done. Among these, since the coating method can be carried out using printing technology without using high temperature and high vacuum conditions, it can be expected to significantly reduce the manufacturing cost of device fabrication, which is an economically preferable process It is.

  An organic semiconductor material used for such a coating method has a combination of heat resistance of 150 ° C. or more and solubility of 1.0% by weight or more at room temperature from the viewpoint of high carrier mobility and process of device fabrication Is preferred. Moreover, it is preferable to have high oxidation resistance. However, low-molecular-weight organic semiconductor materials that combine high carrier mobility, high heat resistance, high solubility, and high oxidation resistance are not known at present.

  At present, as low molecular weight materials, bis [(triisopropylsilyl) ethynyl] pentacene (see, for example, Non-Patent Document 1), dialkyl-substituted benzothienobenzothiophene (see, for example, Patent Document 1), 2,7- Dihexyl dithienobenzodithiophene (see, for example, Patent Document 2 and Patent Document 3) and the like have been proposed.

However, bis [(triisopropylsilyl) ethynyl] pentacene described in Non-Patent Document 1 has a mobility of 0.3 to 1.0 cm ² / Vs of the coating film after heat treatment at 120 ° C., There was a problem that it decreased to 0.2 cm ² / Vs. The dialkyl-substituted benzothienobenzothiophene described in Patent Document 1 also has a problem that the transistor operation is lost when heat treatment is performed at 130 ° C. Furthermore, the dihexyl dithienobenzodithiophene proposed in Patent Document 2 and Patent Document 3 exhibits a mobility of 0.1 cm ² / V · s by the drop casting method, but has a problem in solubility in a solvent at room temperature.

Patent reissued patent WO2008 / 047896 JP 2011/526588 gazette JP, 2012/209329, A

Journal of Polymer Science: Part B: Polymer Physics, 2006, 44, 3631-3641

  The present invention has been made in view of the above problems, and an object thereof is to provide a novel coating type organic semiconductor material having high carrier mobility, high heat resistance, high solubility and high oxidation resistance. It is in.

  As a result of intensive studies to solve the above problems, the present inventor provides an organic thin film transistor having high carrier mobility and high solubility, high heat resistance and high oxidation resistance by using a novel heteroacene derivative. It has been found that it is possible to complete the present invention.

  That is, the present invention relates to a heteroacene derivative represented by the following general formula (1), a method for producing the same, an organic semiconductor layer, and an organic thin film transistor using the same.

（ここで、置換基Ｒ^１〜Ｒ^６は、それぞれ独立して、水素、ハロゲン、炭素数１〜１４のアルキル基、炭素数１〜１４のアシル基、炭素数４〜１６のアリール基、炭素数２〜１４のアルケニル基、炭素数２〜１４のアルキニル基を示す。Ｔ^１及びＴ²は、それぞれ独立して硫黄原子又はセレン原子を示す。但し、Ｔ^１及びＴ²は、同時に硫黄であることはない。）
以下に本発明を詳細に説明する。

(Here, the substituents R ^{1 to} R ⁶ are each independently hydrogen, halogen, an alkyl group having 1 to 14 carbon atoms, an acyl group having 1 to 14 carbon atoms, an aryl group having 4 to 16 carbon atoms, or carbon. an alkenyl group having 2 to 14, .T ¹ and T ² indicates an alkynyl group having 2 to 14 carbon atoms, represents a sulfur atom or a selenium atom independently. However, ^{T 1} and T ^2, at the same time sulfur There is nothing to do.)
The present invention is described in detail below.

The heteroacene derivative used in the present invention is a derivative represented by the above general formula (1), and the substituents R ^{1 to} R ⁶ each independently represent hydrogen, halogen, an alkyl group having 1 to 14 carbon atoms, or carbon atoms An acyl group having 1 to 14 carbon atoms, an aryl group having 4 to 16 carbon atoms, an alkenyl group having 2 to 14 carbon atoms, and an alkynyl group having 2 to 14 carbon atoms.

The halogens in the substituents R ^{1 to} R ⁶ are, for example, chlorine, bromine, iodine, and fluorine, and bromine and iodine are preferable because of high reactivity.

The alkyl group having 1 to 14 carbon atoms in the substituents R ^{1 to} R ⁶ is, for example, methyl group, ethyl group, n-propyl group, n-butyl group, isobutyl group, n-pentyl group, n-hexyl group, n -A linear or branched alkyl group such as heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-dodecyl group, 2-ethylhexyl group, 3-ethylheptyl group, 3-ethyldecyl group and the like. And since it becomes a heteroacene derivative which shows especially high mobility and high solubility among them, a C3-C10 alkyl group is preferable, and n-propyl, n-butyl group, n-pentyl group, n-hexyl group And n-heptyl group and n-octyl group are more preferable.

Examples of the acyl group having 1 to 14 carbon atoms in the substituents R ^{1 to} R ⁶ include a formyl group, acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group, A linear or branched acyl group such as a decanoyl group, a dodecanoyl group, a 2-ethylhexanoyl group, a 3-ethylheptanoyl group, or a 3-ethyldecanoyl group. Among them, an acyl group having a carbon number of 3 to 10 is preferable because it is a heteroacene derivative exhibiting high mobility and high solubility, and is preferably a propionyl group, butyryl group, valeryl group, hexanoyl group, heptanoyl group, octanoyl group. It is further preferred that

The aryl group having 4 to 16 carbon atoms in the substituents R ^{1 to} R ⁶ is, for example, phenyl group, p-tolyl group, p- (n-hexyl) phenyl group, p- (n-octyl) phenyl group, p- Alkyl-substituted phenyl groups such as (2-ethylhexyl) phenyl group, 2-furyl group, 5-fluoro-2-furyl group, 5-methyl-2-furyl group, 5-ethyl-2-furyl group, 5- (n -Propyl) -2-furyl group, 5- (n-butyl) -2-furyl group, 5- (n-pentyl) -2-furyl group, 5- (n-hexyl) -2-furyl group, 5- (N-octyl) -2-furyl group, 5- (2-ethylhexyl) -2-furyl group, 2-thienyl group, 5-fluoro-2-thienyl group, 5-methyl-2-thienyl group, 5-ethyl -2-thienyl group, 5- (n-propyl) -2-thienyl group Group, 5- (n-butyl) -2-thienyl group, 5- (n-pentyl) -2-thienyl group, 5- (n-hexyl) -2-thienyl group, 5- (n-octyl) -2 And alkyl substituted chalcogenophene groups such as -thienyl group, 5- (2-ethylhexyl) -2-thienyl group and the like.

The alkenyl group having 2 to 14 carbon atoms in the substituents R ^{1 to} R ⁶ is, for example, ethenyl group, n-propenyl group, n-butenyl group, n-pentenyl group, n-hexenyl group, n-heptenyl group, n- Examples thereof include alkenyl groups such as octenyl group, n-nonel group, n-decenyl group and n-dodecenyl group.

Examples of the alkynyl group having 2 to 14 carbon atoms in substituents R ^{1 to} R ⁶ include ethynyl group, n-propynyl group, n-butynyl group, n-pentynyl group, n-hexynyl group, n-heptynyl group, and n -Octynyl group, n-nonynyl group, n-decynyl group, n-dodecynyl group.

As the types of substituents in the substituents R ^{1 to} R ⁶ , because of high mobility, R ¹ and R ² are hydrogen, halogen, an alkyl group having 1 to 14 carbon atoms, an acyl group having 1 to 14 carbon atoms, carbon It is selected from the group consisting of an aryl group of 4 to 16 atoms, an alkenyl group of 2 to 14 carbon atoms, and an alkynyl group of 2 to 14 carbon atoms, and it is preferable that R ^{3 to} R ⁶ be hydrogen. It is further preferable that R ¹ and R ² be an alkyl group having 1 to 14 carbon atoms, and R ^{3 to} R ⁶ be hydrogen.

T ¹ and T ² of the heteroacene derivative represented by the general formula (1) of the present invention each independently represent a sulfur atom or a selenium atom. However, T ¹ and T ² can not simultaneously be sulfur. In the present invention, T ¹ and T ² are particularly preferably high mobility when T ¹ is selenium, T ² is sulfur or T ¹ and T ² are selenium, and the synthesis of the raw material is preferable. It is further preferred that T ¹ is selenium and T ² is sulfur for ease of

  The following can be mentioned as specific examples of the heteroacene derivative used in the present invention.

なお、一般式（１）で示されるヘテロアセン誘導体としては、高溶解性、高移動度、及び高耐酸化性のため、２，７−ジ（ｎ−ブチル）ジチエノベンゾジセレノフェン（化合物２）、２，７−ジ（ｎ−ペンチル）ジチエノベンゾジセレノフェン（化合物３）、２，７−ジ（ｎ−ヘキシル）ジチエノベンゾジセレノフェン（化合物４）、２，７−ジ（ｎ−ヘプチル）ジチエノベンゾジセレノフェン（化合物５）、２，７−ジ（ｎ−オクチル）ジチエノベンゾジセレノフェン（化合物６）、２，７−ジ（ｎ−ノニル）ジチエノベンゾジセレノフェン（化合物７）が好ましい。

In addition, as the heteroacene derivative represented by the general formula (1), 2,7-di (n-butyl) dithienobenzodiselenophen (compound 2) because of high solubility, high mobility, and high oxidation resistance. ), 2,7-di (n-pentyl) dithienobenzo diselenophene (compound 3), 2,7-di (n-hexyl) dithienobenzo diselenophene (compound 4), 2,7-di (compound 3) n-Heptyl) dithienobenzodiselenophene (compound 5), 2,7-di (n-octyl) dithienobenzodiselenophene (compound 6), 2,7-di (n-nonyl) dithienobenzodi Selenophene (compound 7) is preferred.

As a method for producing the heteroacene derivative used in the present invention, any production method can be used as long as the heteroacene derivative can be produced. For example, in the case of producing a heteroacene derivative in which the substituents R ¹ and R ² are hydrogen or an alkyl group having 1 to 14 carbon atoms, and the substituents R ^{3 to} R ⁶ are hydrogen, the following steps (A) to (D) The heteroacene derivative (compound (1a) in the following reaction scheme) can be produced according to the production method.
(A) Step; 1,4-di (3-halochalcogenophenyl)-with 3-halochalcogenophenyl-2-zinc derivative and 1,4-dibromo-2,5-difluorobenzene in the presence of a palladium catalyst A step of producing 2,5-difluorobenzene.
Step (B): Unsubstituted by intramolecular cyclization of 1,4-di (3-halochalcogenophenyl) -2,5-difluorobenzene obtained by Step (A) in the presence of alkali metal salt of chalcogenide Process of manufacturing heteroacene.
Step (C): A step of producing diacyl heteroacene by Friedel-Crafts acylation reaction of unsubstituted heteroacene and acyl chloride compound in the presence of aluminum chloride as a catalyst.
Step (D): a step of subjecting the diacyl heteroacene obtained in step (C) to a reduction reaction to produce a heteroacene derivative.

  Then, a more specific production method which is preferable because the number of reaction steps is small is shown in the following reaction scheme.

（ここで、置換基Ｒ^１及びＲ^２は、それぞれ独立して、炭素数１〜１４のアルキル基を示し、置換基Ｒ^７は、水素、炭素数１〜１３のアルキル基を示す。Ｔ^１及びＴ²は、それぞれ独立して硫黄原子又はセレン原子を示す。但し、Ｔ^１及びＴ²は、同時に硫黄であることはない。置換基Ｘ^１及びＸ^２は、それぞれ独立して、ハロゲンを示す。）
ここで、（Ａ）工程は、パラジウム触媒の存在下、３−ハロカルコゲノフェニル−２−亜鉛誘導体と１，４−ジブロモ−２，５−ジフルオロベンゼンのクロスカップリングにより１，４−ジ（３−ハロカルコゲノフェニル）−２，５−ジフルオロベンゼンを製造する工程である。

(Here, the substituents R ¹ and R ² each independently represent an alkyl group having 1 to 14 carbon atoms, and the substituent R ⁷ represents hydrogen or an alkyl group having 1 to 13 carbon atoms. T ^1. And T ² each independently represent a sulfur atom or a selenium atom, provided that T ¹ and T ² are not simultaneously sulfur The substituents X ¹ and X ² each independently represent a halogen Show)
Here, the step (A) is carried out by cross-coupling of a 3-halochalcogenophenyl-2-zinc derivative with a 1,4-dibromo-2,5-difluorobenzene in the presence of a palladium catalyst. It is a step of producing 3-halochalcogenophenyl) -2,5-difluorobenzene.

  The 3-halochalcogenophenyl-2-zinc derivative is prepared by using, for example, an organometallic reagent such as isopropylmagnesium bromide, ethylmagnesium chloride, phenylmagnesium chloride, and the like. After exchanging with halide (preparation of Grignard reagent), it can be prepared by exchanging metal with zinc chloride. It is also possible to prepare a Grignard reagent of 2,3-dihalochalcogenophene using magnesium metal instead of the organometallic reagent. The conditions for preparing the 2,3-dihalochalcogenophene Grignard reagent are, for example, carried out in a solvent such as tetrahydrofuran (hereinafter referred to as THF) or diethyl ether within a temperature range of −80 ° C. to 50 ° C. can do. A 3-halochalcogenophenyl-2-zinc derivative can be prepared by reacting zinc chloride with a solution of the Grignard reagent. Zinc chloride may be used as it is, or it may be THF or diethyl ether solution. The reaction temperature of the Grignard reagent and zinc chloride can be carried out within a range of -80 ° C to 30 ° C.

  As a halogen of 3-halo chalcogeno phenyl 2-zinc derivative, chlorine, a bromine, a fluorine, and an iodine can be mentioned, for example. Specifically, 3-halochalcogenophenyl-2-zinc derivatives are, for example, 3-chlorothienyl-2-zinc derivatives, 3-bromothienyl-2-zinc derivatives, 3-iodothienyl-2-zinc derivatives, 3-fluorothienyl-2-zinc derivative, 3-chloroselenophenyl-2-zinc derivative, 3-bromoselenophenyl-2-zinc derivative, 3-iodoselenophenyl-2-zinc derivative, 3-fluoroselenophenyl-2 -Zinc derivatives and the like can be mentioned, and among them, 3-chlorothienyl-2-zinc derivatives and 3-bromothienyl-2-zinc derivatives are preferable because they are particularly excellent in reaction efficiency.

  1,4-di (3-halo chalco) by cross coupling of the prepared 3-halochalcogenophenyl-2-zinc derivative with 1,4-dibromo-2,5-difluorobenzene in the presence of a palladium catalyst Genophenyl) -2,5-difluorobenzene can be synthesized. In this case, examples of the palladium catalyst include tetrakis (triphenylphosphine) palladium, bis (triphenylphosphine) dichloropalladium, and the like, and the reaction temperature is 20 to 80 ° C. Can.

  The products obtained by the reaction include 1,4-di (3-chlorothienyl) -2,5-difluorobenzene, 1,4-di (3-bromothienyl) -2,5-difluorobenzene, 1, 4-di (3-iodothienyl) -2,5-difluorobenzene, 1,4-di (3-fluorothienyl) -2,5-difluorobenzene, 1,4-di (3-chloroselenophenyl) -2 , 5-difluorobenzene, 1,4-di (3-bromoselenophenyl) -2,5-difluorobenzene, 1,4-di (3-iodoselenophenyl) -2,5-difluorobenzene, 1,4- Di (3-fluorothienyl) -2,5-difluorobenzene is mentioned.

  Step (B) is a step of producing an unsubstituted heteroacene by intramolecular cyclization of 1,4-di (3-halochalcogenophenyl) -2,5-difluorobenzene in the presence of a chalcogenated alkali metal salt. .

  As the chalcogenide alkali metal salt, for example, sodium selenide, potassium selenide, lithium selenide, rubidium selenide, cesium selenide, sodium sulfide, potassium sulfide, lithium sulfide, rubidium sulfide, cesium sulfide, and hydrate thereof The intramolecular cyclization reaction is carried out in a solvent such as N-methylpyrrolidone (hereinafter referred to as NMP) or N, N-dimethylformamide (hereinafter referred to as DMF). It can be carried out in a temperature range of 80 ° C to 200 ° C.

  A commercially available product and one prepared by a known method can be used as the chalcogenide alkali metal salt used in this step. For example, sodium selenide can be used as it is obtained by reducing selenium with sodium borohydride in ethanol.

  Step (C) is a step of producing diacyl heteroacene by Friedel-Crafts acylation reaction of unsubstituted heteroacene and an acyl chloride compound in the presence of aluminum chloride as a catalyst.

  Examples of the acyl chloride compound include formyl chloride, acetyl chloride, propionyl chloride, butyryl chloride, isobutyryl chloride, valeroyl chloride, hexanoyl chloride, heptanoyl chloride, octanoyl chloride, 2-ethylhexanoyl chloride, noninoyl chloride, decanoyl chloride, chloride Examples include dodecanoyl, tetradecanoyl chloride and the like. The Friedel-Crafts acylation reaction can be performed, for example, in a solvent such as dichloromethane, 1,2-dichloroethane, toluene or the like at a temperature range of 0 ° C to 40 ° C.

  Step (D) is a step for producing a heteroacene derivative by subjecting diacyl heteroacene to a reduction reaction.

  In the reduction reaction of diacyl heteroacene, for example, sodium borohydride / aluminum chloride or lithium aluminum hydride / aluminum chloride is used as a reducing agent, and in a solvent of THF, diethyl ether, diisopropyl ether, or methyl tertiary butyl ether, It can be carried out in a temperature range of 10 ° C to 80 ° C. For example, it can also be carried out in a temperature range of 80 ° C. to 250 ° C. in the presence of potassium hydroxide or sodium hydroxide in diethylene glycol, ethylene glycol or triethylene glycol, using hydrazine as a reducing agent.

  Furthermore, the prepared heteroacene derivative can be purified by subjecting to column chromatography etc., and as separation agents in that case, for example, silica gel, activated alumina, solvents as hexane, heptane, toluene, dichloromethane, chloroform Etc. can be mentioned.

  The prepared heteroacene derivative can be decolorized and purified in a solution by using activated carbon, zeolite, activated clay and the like, and examples of the solvent include hexane, heptane, toluene, dichloromethane, chloroform and the like.

  The produced heteroacene derivative may be further purified by recrystallization, and the number of recrystallizations is preferably 2 to 5 in order to improve the purity. The purity can be improved by increasing the number of recrystallizations. Examples of the solvent used for recrystallization include hexane, heptane, octane, toluene, xylene, chloroform, chlorobenzene, dichlorobenzene, and the like, and a mixture of any ratio thereof may be used. As the recrystallization method, a solution of a heteroacene derivative is prepared by heating (the concentration of the solution at that time is preferably in the range of 0.01 to 10.0% by weight in order to efficiently remove impurities, The range of 5.0% by weight is more preferable), and the solution is cooled to precipitate and isolate crystals of the heteroacene derivative, but the final cooling temperature at the time of isolation is improved in purity and recovery rate. Therefore, the temperature is preferably in the range of -20 ° C to 40 ° C. In addition, when measuring purity, it is possible to analyze by liquid chromatography.

  The heteroacene derivative of the present invention can be made into a solution for forming an organic semiconductor layer by dissolving in a suitable solvent. As the solvent, any solvent can be used as long as it can dissolve the heteroacene derivative represented by the general formula (1), and when forming the organic semiconductor layer, the drying rate of the solvent is preferably selected. An organic solvent having a boiling point of 100 ° C. or higher at normal pressure is preferable.

  There is no restriction | limiting in particular as a solvent which can be used by this invention, For example, aromatic, such as toluene, mesitylene, o-xylene, isopropylbenzene, pentylbenzene, cyclohexylbenzene, 1,2,4-trimethylbenzene, tetralin, indane Hydrocarbons, anisole, 2-methylanisole, 3-methylanisole, 2,3-dimethylanisole, 3,4-dimethylanisole, 2,6-dimethylanisole, ethylphenyl ether, butylphenyl ether, 1,2- Aromatic ethers such as methylenedioxybenzene and 1,2-ethylenedioxybenzene, aromatic halogen compounds such as chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene and 1,4-dichlorobenzene, cyclohexanone , Octane, decane, Saturated hydrocarbons such as decane and decalin, dipropylene glycol dimethyl ether, dipropylene glycol diacetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3 -Butylene glycol diacetate, 1,3-butylene glycol diacetate, 1,6-hexanediol diacetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono Glycols such as butyl ether acetate, phenyl acetate, cyclohexanol acetate Esters such as 3-methoxybutyl acetate can be mentioned, and among them, since it has an appropriate drying rate, preferably toluene, o-xylene, mesitylene, 1,2,4-trimethylbenzene, tetralin, Indane, anisole, 2-methyl anisole, 3-methyl anisole, 2,3-dimethyl anisole, 3,4- dimethyl anisole, 2, 6-dimethyl anisole, ethyl phenyl ether, butyl phenyl ether, 1,2- methylene dioxy Benzene, 1,2-ethylenedioxybenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, more preferably toluene, o-xylene, mesitylene, tetralin, indane, Anisole, 2-Methylanisole, 3 Methyl anisole, 2,3-dimethyl anisole, 3,4-dimethyl anisole, 2,6-dimethyl anisole.

  As the solvent used in the present invention, it is possible to use one type of solvent alone or to use two or more types of solvents having different properties such as boiling point, polarity, solubility parameter and the like.

  The temperature for mixing and dissolving the heteroacene derivative represented by the general formula (1) in a solvent is preferably in the temperature range of 0 to 80 ° C., preferably 10 to 60 ° C., for the purpose of promoting dissolution. More preferably,

  In addition, the time for dissolving and mixing the heteroacene derivative represented by the general formula (1) in an organic solvent is preferably 1 minute to 1 hour in order to obtain a uniform solution.

  In the present invention, when the concentration of the heteroacene derivative represented by the general formula (1) in the solution for forming an organic semiconductor layer of the present invention is in the range of 0.1 to 10.0% by weight, handling becomes easy and the organic semiconductor layer It becomes more excellent by the efficiency at the time of formation. In addition, when the viscosity of the solution for forming an organic semiconductor layer is in the range of 0.3 to 10 mPa · s, more preferable coatability is exhibited.

  The solution can be suitably applied to the production of an organic thin film by a coating method because it can be prepared at a relatively low temperature because the heteroacene derivative itself has an appropriate cohesive property and has oxidation resistance. . That is, since it is not necessary to remove air from the atmosphere, the coating process can be simplified. Further, the solution may contain, as a binder, polymers such as polystyrene, poly (α-methylstyrene), polyvinyl naphthalene, ethylene-norbornene copolymer, polyphenylene ether, and polymethyl methacrylate. The concentration of these polymer binders is preferably 0.1 to 10.0% by weight for an appropriate solution viscosity. In addition, the solution preferably has a viscosity in the range of 0.5 to 50 mPa · s in order to have excellent coatability.

  The coating method for forming the organic semiconductor layer using the solution for forming an organic semiconductor layer of the present invention is not particularly limited as long as it is a method capable of forming an organic semiconductor layer, and, for example, spin coating, drop casting, dip Simple coating methods such as coating, cast coating, etc .; printing methods such as dispenser, inkjet, slit coating, blade coating, flexographic printing, screen printing, gravure printing, offset printing, etc. can be mentioned. In order to be able to do this, spin coating and inkjet are preferable.

  After applying the solution for forming an organic semiconductor layer of the present invention, the solvent can be dried and removed to form an organic semiconductor layer.

  When the solvent is dried and removed from the applied organic semiconductor layer, the drying conditions are not particularly limited, and for example, the solvent can be removed by drying under normal pressure or reduced pressure.

  There is no particular limitation on the temperature at which the organic solvent is dried and removed from the applied organic semiconductor layer, but the organic solvent can be dried and removed from the applied organic semiconductor layer efficiently, and an organic semiconductor layer can be formed, It is preferable to carry out in the temperature range of 10-150 degreeC.

  When the organic solvent is dried and removed from the applied organic semiconductor layer, the crystal growth of the heteroacene derivative represented by the general formula (1) can be controlled by adjusting the evaporation rate of the organic solvent to be removed.

  The film thickness of the organic semiconductor layer formed by the solution for forming an organic semiconductor layer of the present invention is not limited, and is preferably in the range of 1 nm to 1 μm, and in the range of 10 nm to 300 nm, because good carrier migration is obtained It is further preferred that

  The obtained organic semiconductor layer may be annealed at 40 to 180 ° C. after forming the organic semiconductor layer.

  The organic semiconductor layer formed from the solution for forming an organic semiconductor layer of the present invention can be used as an organic semiconductor layer of an organic semiconductor device, particularly an organic thin film transistor.

  The organic thin film transistor can be obtained by laminating an organic semiconductor layer provided with a source electrode and a drain electrode and a gate electrode on a substrate via an insulating layer, and the organic semiconductor layer is formed on the organic semiconductor layer according to the present invention. By using an organic semiconductor layer formed of a solution, an organic thin film transistor exhibiting excellent semiconductor and electrical characteristics can be obtained.

  The structure by the cross-sectional shape of a general organic thin-film transistor is shown in FIG. Here, (A) is a bottom gate-top contact type, (B) is a bottom gate-bottom contact type, (C) is a top gate-top contact type, and (D) is a top gate-bottom contact type. 1 is an organic semiconductor layer, 2 is a substrate, 3 is a gate electrode, 4 is a gate insulating layer, 5 is a source electrode, 6 is a drain electrode, and is formed from the solution for forming an organic semiconductor layer of the present invention. The organic semiconductor layer to be formed can be applied to any organic thin film transistor.

  The substrate according to the present invention is not particularly limited. For example, polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate, polymethyl acrylate, polyethylene, polypropylene, polystyrene, cyclic polyolefin, fluorinated cyclic polyolefin, polyimide, polycarbonate, polyvinyl phenol, Plastic substrates such as polyvinyl alcohol, poly (diisopropyl fumarate), poly (diethyl fumarate), poly (diisopropyl maleate), polyether sulfone, polyphenylene sulfide, cellulose triacetate; glass, quartz, aluminum oxide, silicon, highly doped silicon , Inorganic materials such as silicon oxide, tantalum dioxide, tantalum pentoxide, indium tin oxide, etc .; gold, copper, chromium Titanium, mention may be made of metal such as aluminum substrate, or the like. When highly doped silicon is used for the substrate, the substrate can also serve as the gate electrode.

  The gate electrode according to the present invention is not particularly limited. For example, aluminum, gold, silver, copper, highly doped silicon, tin oxide, indium oxide, indium tin oxide, chromium, titanium, tantalum, graphene, carbon nanotube, etc. And inorganic materials; organic materials such as doped conductive polymers (eg, PEDOT-PSS).

  The inorganic material can be used as a metal nanoparticle ink. The solvent in this case is a polar solvent such as water, methanol, ethanol, isopropanol, 1-butanol, 2-butanol and the like because of its appropriate dispersibility; hexane, heptane, octane, decane, dodecane, tetradecane, etc. 14 aliphatic hydrocarbon solvents; toluene, xylene, mesitylene, ethylbenzene, pentylbenzene, hexylbenzene, octylbenzene, cyclohexylbenzene, tetralin, indane, anisole, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1, It is preferable that they are C7-C14 aromatic hydrocarbon solvents, such as 2-dimethyl anisole, a 2, 3- dimethyl anisole, a 3, 4- dimethyl anisole. After the application of the nanoparticle ink, annealing is preferably performed in a temperature range of 80 ° C. to 200 ° C. in order to improve the conductivity.

  The gate insulating layer according to the present invention is not particularly limited. For example, silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, titanium oxide, tantalum dioxide, tantalum pentoxide, indium tin oxide, tin oxide, vanadium oxide, titanium Inorganic materials such as barium titanate and bismuth titanate; polymethyl methacrylate, polymethyl acrylate, polyimide, polycarbonate, polyvinyl phenol, polyvinyl alcohol, poly (diisopropyl fumarate), poly (diethyl fumarate), polyethylene terephthalate, polyethylene naphthalate, Ethyl polycinnamate, methyl polycinnamate, ethyl polycrotonate, polyether sulfone, polypropylene-co-1-butene, polyisobutylene, polypropylene, polycyclopentane Polymer insulation materials such as polycyclohexane, polycyclohexane-ethylene copolymer, polyfluorinated cyclopentane, polyfluorinated cyclohexane, polyfluorinated cyclohexane-ethylene copolymer, CytopTM, TeflonTM, etc. In addition, since the manufacturing method is simple, a polymer insulating material (polymer gate insulating layer) to which a coating method can be applied is preferable.

  There is no restriction | limiting in particular as a solvent used for melt | dissolving this polymer material, For example, C6-C14 aliphatic hydrocarbon solvents, such as hexane, heptane, octane, decane, dodecane, tetradecane; THF, 1, 2- dimethoxy Ether solvents such as ethane and dioxane; alcohol solvents such as ethanol, isopropyl alcohol, 1-butanol, 2-butanol and 2-ethylhexanol; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, diisopropyl ketone and acetophenone; acetic acid Ester solvents such as ethyl, γ-butyrolactone, cyclohexanol acetate and 3-methoxybutyl acetate; Amides solvents such as DMF and NMP; Dipropylene glycol dimethyl ether, Dipropylene glycol diacetate, Di Lopylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1,3-butylene glycol diacetate, 1,6-hexanediol diester Glycol solvents such as acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate; perfluorohexane, perfluorooctane, 2- (pentafluoroethyl) And fluorinated solvents such as hexane and 3- (pentafluoroethyl) heptane.

  The concentration of the polymer insulating material is, for example, 0.1 to 10.0% by weight at a temperature of 20 to 40 ° C. There is no restriction | limiting in the film thickness of the insulating layer obtained in the said density | concentration, From an insulation-resistant viewpoint, Preferably it is 100 nm-1 micrometer, More preferably, it is 150 nm-900 nm.

  The surfaces of these gate insulating layers are, for example, octadecyltrichlorosilane, decyltrichlorosilane, decyltrimethoxysilane, octyltrichlorosilane, octadecyltrimethoxysilane, β-phenethyltrichlorosilane, β-phenethyltrimethoxysilane, and phenyltrimethylsilane. It is also possible to use silanes such as chlorosilane and phenyltrimethoxysilane; phosphonic acids such as octadecylphosphonic acid, decylphosphonic acid and octylphosphonic acid; and silylamines such as hexamethyldisilazane. Generally, by performing surface treatment of the gate insulating layer, it is preferable that the carrier mobility and the current on / off ratio be improved and the threshold voltage be lowered in order to increase the crystal grain size of the organic semiconductor material and to improve the molecular orientation. The result is obtained.

  The material of the source electrode and the drain electrode of the organic thin film transistor of the present invention is not particularly limited, and the same material as the gate electrode can be used, and may be the same as or different from the material of the gate electrode. May be stacked. In order to increase the carrier injection efficiency, surface treatment can be performed on these electrode materials. Examples of the surface treatment agent used for surface treatment include benzenethiol, pentafluorobenzenethiol, 4-fluorobenzenethiol, 4-methoxybenzenethiol and the like.

The organic thin film transistor of the present invention preferably has a carrier mobility of 0.5 cm ² / V · s or more, for fast operability. In addition, it is preferable that the current on / off ratio is 1.0 × 10 ⁶ or more because of high switching characteristics.

  The organic thin film transistor of the present invention is used for organic semiconductor layers of transistors such as electronic paper, organic EL display, liquid crystal display, IC tag (RFID tag), pressure sensor, biosensor, etc .; organic EL display material; organic semiconductor laser material; It can be used for solar cell materials; electronic materials such as photonic crystal materials, and the heteroacene derivative represented by the general formula (1) is a crystalline thin film. Therefore, it is preferably used as a semiconductor layer for organic thin film transistors. .

  The novel heteroacene derivative of the present invention provides an organic thin film transistor that exhibits excellent semiconductor properties by coating because it has high carrier mobility and high heat resistance, high solubility, and high oxidation resistance. It is possible and its effect is extremely high.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

¹ H NMR spectrum, mass spectrum (MS), and liquid chromatography-mass spectrum (LCMS) analysis were used for product identification.

¹ H NMR spectrum analyzer; Nippon Electronics, (trade name) Delta V5 (400 MHz)
Mass spectrum (MS) analyzer; manufactured by Nippon Denshi, (trade name) JEOL JMS-700
MS ionization; electron impact (EI) method (70 electron volts)
Sample introduction; direct introduction Liquid chromatography-mass spectrum (LCMS) analyzer; Bruker Daltonics, (trade name) microTOF focus
MS ionization; atmospheric pressure chemical ionization (APCI) method LC conditions; conditions described below confirmation of the progress of the reaction, etc. are thin layer chromatography, gas chromatography (GC), gas chromatography-mass spectrometry (GCMS), liquid chromatography (LC) analysis was used.

Gas chromatography analyzer; manufactured by Shimadzu Corporation (trade name) GC14B
Column; manufactured by J & W Scientific, (trade name) DB-1, 30 m
Gas chromatography-mass spectrum analyzer; manufactured by PerkinElmer, (trade name) Auto System XL (MS unit: Turbomass Gold)
Column; manufactured by J & W Scientific, (trade name) DB-1, 30 m.

  Liquid chromatography analysis was used to measure the purity of the heteroacene derivative.

Liquid chromatography analyzer; manufactured by Tosoh (controller; PX-8020, pump; CCPM-II, degasser; SD-8022)
Column: Tosoh Corporation (trade name) ODS-100V, 5 μm, 4.6 mm × 250 mm
Column temperature; 30 ° C
Eluent; dichloromethane: acetonitrile = 2: 8 (volume ratio)
Flow rate; 1.0 ml / min detector; UV (manufactured by Tosoh, (trade name) UV-8020, wavelength: 254 nm).

Synthesis Example 1 (Synthesis of 1,4-di (3-bromothienyl) -2,5-difluorobenzene) (Step (A)))
Under a nitrogen atmosphere, 14.6 g (60.2 mmol) of 2,3-dibromothiophene (Wako Pure Chemical Industries) and 160 ml of THF (dehydration grade) were added to a 500 ml three-necked flask. The solution was cooled to 0 ° C., and 31.5 ml (63.0 mmol) of a THF solution of ethylmagnesium chloride (Sigma-Aldrich, 2.0M) was added dropwise. The mixture was aged at 0 ° C. for 10 minutes. On the other hand, 9.98 g (73.2 mmol) of zinc chloride (Wako Pure Chemical Industries, Ltd.) and 100 ml of THF (dehydration grade) were added to another 1000 ml three-necked flask under a nitrogen atmosphere, and cooled to 0 ° C. To this white fine slurry solution, the 2,3-dibromothiophene Grignard reagent prepared above was added dropwise using a Teflon cannula, and further 5 ml of THF (dehydrated grade) was added to a 500 ml three-necked flask and a Teflon canal. Nuller was added while washing. The resulting mixture was stirred at 0 ° C. for 30 minutes and further at room temperature for 15 minutes. Into a white fine slurry of the formed 3-bromothienyl-2-zinc derivative, 5.44 g (20.0 mmol) of 1,4-dibromo-2,5-difluorobenzene (Wako Pure Chemical Industries) and tetrakis (triol) as a catalyst Phenylphosphine) palladium (Tokyo Kasei Kogyo) 347 mg (0.300 mmol, 1.50 mol% based on 1,4-dibromo-2,5-difluorobenzene) was added. After carrying out the reaction at 50 ° C. for 25 hours, the vessel was water-cooled and the reaction was stopped by adding 90 ml of 1N hydrochloric acid. It was extracted with toluene and the organic phase was washed with brine and dried over anhydrous sodium sulfate. After concentration under reduced pressure, the obtained residue was purified by silica gel column chromatography (developing solvent: toluene). After concentration under reduced pressure, the obtained residue was washed with 30 ml of hexane. The resulting residue was recrystallized from heptane / toluene = 2/1 to give 5.27 g of a pale yellow solid of 1,4-di (3-bromothienyl) -2,5-difluorobenzene (yield 60) %).
¹ H NMR (CDCl ₃ , 21 ° C.): δ = 7.44 (d, J = 5.4 Hz, 2H), 7.39 (t, J = 7.8 Hz, 2H), 7.11 (d, J = 5.4 Hz, 2 H).
MS m / z: 436 (M ^<+> , 100%), 276 (M ^<+ > ^- 2Br, 13).

Example 1 (Synthesis of Unsubstituted Heteroacene (Compound 1)) (Step (B))
Sodium selenide was prepared as follows according to the method described in Organic Letters (U.S.A.), 2009, Vol. 11, pp. 2473-2475, and was used as a raw material for an intramolecular cyclization reaction.

Under a nitrogen atmosphere, 691 mg (8.75 mmol) of selenium (Wako Pure Chemical Industries) and 20 ml of ethanol (dehydrated grade) were added to a 100 ml Schlenk reaction vessel. After ice cooling, 335 mg (8.86 mmol) of sodium borohydride (Wako Pure Chemical Industries, Ltd.) was added little by little, and the mixture was stirred for 40 minutes under ice cooling to prepare sodium selenide. Here, 46 ml of NMP (dehydration grade) was added and heated to 120 ° C. to distil off ethanol. After cooling to room temperature, 1.09 g (2.50 mmol) of 1,4-di (3-bromothienyl) -2,5-difluorobenzene obtained in Synthesis Example 1 was added. The resulting mixture was heated at 160 ° C. for 5 hours and then cooled to room temperature. Water was added to the reaction mixture under ice cooling, and the precipitated solid was filtered. The solid was washed with water and methanol, dried, and recrystallized from toluene to obtain 412 mg of a pale yellow solid of unsubstituted heteroacene (yield 42%).
¹ H NMR (CDCl ₃ , 23 ° C.): δ = 8.33 (s, 2H), 7.49 (d, J = 5.5 Hz, 2H), 7.35 (d, J = 5.2 Hz, 2H ).
MS m / z: 400 (M ⁺ +2, 39%), 398 (M ⁺ , 100%), 396 (M ⁺ -2, 85%), 394 (M ⁺ -64, 61%), 199 (M ⁺ / 2, 15).

Example 2 (Synthesis of Diacyl Heteroacene) (Step (C))
To the 200 ml three-necked flask, 682 mg (1.72 mmol) of unsubstituted heteroacene synthesized in Example 1 and 54 ml of dichloromethane (dehydrated grade) were added. The mixture was ice-cooled, and 801 mg (6.01 mmol) of aluminum chloride (Wako Pure Chemical Industries, Ltd.) and 721 mg (5.36 mmol) of hexanoyl chloride (Sigma-Aldrich) were added. The resulting mixture was stirred at room temperature for 50 hours, cooled with ice, and quenched by addition of water. The resulting mixture was heated to distill off dichloromethane. The obtained yellow slurry liquid was filtered, and the yellow solid was washed with water, 1 M hydrochloric acid, water and methanol and then dried under reduced pressure to obtain 844 mg of a diacyl heteroacene yellow solid (yield 83%).
¹ H NMR (heavy benzene, 70 ° C.): δ = 7.79 (s, 2 H), 7. 27 (s, 2 H), 2.62 (t, J = 7.3 Hz, 4 H), 1.76 ( m, 4 H), 1.32 (m, 8 H), 0.899 (t, J = 6.9 Hz, 6 H).

Example 3 (Synthesis of Heteroacene Derivative (Compound 4)) (Step (D))
Under a nitrogen atmosphere, 826 mg (1.39 mmol) of the diacyl heteroacene synthesized in Example 2 and 50 ml of THF (dehydrated grade) were added to a 200 ml three-necked flask. The mixture was ice-cooled, and 934 mg (7.00 mmol) of aluminum chloride (Wako Pure Chemical Industries, Ltd.) and 547 mg (14.5 mmol) of sodium borohydride (Wako Pure Chemical Industries) were added in this order. The mixture was stirred under heating and reflux for 9 hours, cooled with water, and water was added to quench the reaction. The mixture was extracted with toluene, and the organic phase was washed with 1 M hydrochloric acid, saturated brine and dried over anhydrous sodium sulfate. The reaction solution is concentrated under reduced pressure, and the obtained residue is purified by silica gel column chromatography (developing solvent: hexane / toluene = 10/1), and further, the resulting hexane / toluene = 3/1 is recrystallized and purified three times to obtain a heteroacene derivative 406 mg of pale yellow crystals of (compound 4) were obtained (yield 52%).

The purity of the obtained heteroacene derivative (compound 4) was 99.3% by liquid chromatography.
¹ H NMR (Heavy benzene, 23 ° C.): δ = 7.87 (s, 2 H), 6.67 (s, 2 H), 2.67 (t, J = 7.8 Hz, 4 H), 1.60 ( m, 4 H), 1. 24 (m, 12 H), 0.906 (t, J = 7.3 Hz, 6 H).
LCMS m / z: 567 (M ^{+ +1,} 100%), 565 (M ⁺ -1, 96%), 563 (M ⁺ -3, 65%), 399 (M ⁺ -C ₅ H ₁₁ , 57), _{^{328 (M + -2C 5 H 11}} , 47).
Melting point: 168.2-168.5 ° C.

Example 4 (Synthesis of Diacyl Heteroacene) (Step (C))
A yellow solid of diacylheteroacene was obtained in a yield of 85% by the same method as in Example 2 except that butyryl chloride (Sigma-Aldrich) was used instead of hexanoyl chloride used in Example 2.

Example 5 (Synthesis of Heteroacene Derivative (Compound 2)) (Step (D))
A light yellow crystal of a heteroacene derivative (compound 2) is obtained in the same manner as in Example 3, except that the diacyl heteroacene synthesized in Example 4 is used instead of the diacyl heteroacene synthesized in Example 2. Obtained at 55%.

Example 6 (Synthesis of Diacyl Heteroacene) (Step (C))
A yellow solid of diacylheteroacene was obtained in a yield of 81% by the same method as in Example 2 except that octanoyl chloride (Sigma-Aldrich) was used instead of hexanoyl chloride used in Example 2.

Example 7 (Synthesis of Heteroacene Derivative (Compound 6)) (Step (D))
A light yellow crystal of a heteroacene derivative (compound 6) is obtained in the same manner as in Example 3 except that the diacyl heteroacene synthesized in Example 6 is used instead of the diacyl heteroacene synthesized in Example 2. Obtained at 49%.

Example 8
(Preparation of organic semiconductor layer forming solution)
Under air, 13.5 mg of the heteroacene derivative (compound 4) obtained in Example 3 and 1.21 g of toluene (Wako Pure Chemical Industries, pure grade) are added to a 10 ml sample tube, heated and dissolved at 50 ° C., and room temperature It was left under (25 ° C.) for 12 hours. Since no crystal precipitation was observed and the solution state of 1.10% by weight was maintained, it was confirmed that the material was suitable for film formation by inkjet.

(Preparation of organic semiconductor layer)
Under air, 1.5 mg of the heteroacene derivative (compound 4) obtained in Example 3 and 0.75 g of toluene (Wako Pure Chemical Industries, pure grade) were added to a 10 ml sample tube and heated to 40 ° C. to prepare a solution (0.20% by weight).

  A syringe was filled with 0.5 ml of the obtained solution on an n-type highly doped silicon substrate (Miyoshi, resistance value: 0.004Ω, with a 200 nm silicon oxide film on the surface) having a diameter of 2 inches under air. Drop cast solution through a 2 μm filter. The film was naturally dried at room temperature (25 ° C.) to prepare a thin film of a heteroacene derivative (compound 4) having a thickness of 54 nm.

(Fabrication of organic thin film transistor)
A shadow mask with a channel length of 40 μm and a channel width of 500 μm was placed on the organic thin film, and gold was vacuum deposited to form an electrode, whereby a bottom gate-top contact type p-type organic thin film transistor was produced.

Evaluation of transfer characteristics by scanning the gate voltage (Vg) from +5 to -80 V in 1 V steps with a drain voltage (Vd = -80 V) using a semiconductor parameter analyzer (Keithley 4200 SCS) for the electrical properties of the produced organic thin film transistor Did. The carrier mobility of the holes was 0.79 cm ² / V · s, and the current on / off ratio was 2.0 × 10 ⁷ .

Furthermore, the electrical properties of the organic thin film transistor after annealing at 150 ° C. for 15 minutes were measured. The hole carrier mobility was 0.75 cm ² / V · s, the current on / off ratio was 1.7 × 10 ⁷ , and almost no deterioration in performance due to heat treatment was observed.

Example 9
(Preparation of organic semiconductor layer forming solution)
Under air, 12.9 mg of the heteroacene derivative (compound 6) obtained in Example 7 and 1.16 g of toluene (Wako Pure Chemical Industries, pure grade) were added to a 10 ml sample tube, and dissolved by heating to 50 ° C. It was left under (25 ° C.) for 12 hours. Since no crystal precipitation was observed and the solution state of 1.10% by weight was maintained, it was confirmed that the material was suitable for film formation by inkjet.

(Preparation of organic semiconductor layer)
Under air, 1.4 mg of the heteroacene derivative (compound 6) obtained in Example 7 and 0.75 g of toluene (Wako Pure Chemical Industries, pure grade) were added to a 10 ml sample tube and heated to 40 ° C. to prepare a solution (0.19% by weight).

  In a syringe, 0.5 ml of the resulting solution is placed on a silicon substrate (Miyoshi, resistance value: 0.001 to 0.004Ω, with a 200 nm silicon oxide film on the surface) of n-type n-type having a diameter of 2 inches in a syringe. The solution was packed and dropped through a 0.2 μm filter. It air-dried at room temperature (25 degreeC), and produced the thin film of the heteroacene derivative (compound 6) with a film thickness of 49 nm.

(Fabrication of organic thin film transistor)
By the same method as in Example 8, a bottom gate-top contact type p-type organic thin film transistor was produced.

The carrier mobility of holes was 0.86 cm ² / V · s, and the current on / off ratio was 2.5 × 10 ⁷ . After annealing for 15 minutes at 150 ° C., the carrier mobility of holes is 0.82 cm ² / V · s, the current on / off ratio is 2.2 × 10 ⁷ , and a decrease in performance due to heat treatment is observed. It was not.

Comparative Example 1
(Preparation of solution for forming organic semiconductor layer)
Under air, add 14.5 mg of di n-octylbenzothienobenzothiophene (C8-BTBT, Sigma-Aldrich) and 1.20 g of toluene (Wako Pure Chemical Industries, Pure Grade) to a 10 ml sample tube and heat to 50 ° C After dissolution, it was left at room temperature (25 ° C.) for 12 hours. Since no crystal precipitation was observed and the solution state of 1.19% by weight was maintained, it was confirmed that the material was suitable for film formation by inkjet.

(Preparation of organic semiconductor layer)
Under air, 1.5 mg of di-n-octylbenzothienobenzothiophene and 0.75 g of toluene (Wako Pure Chemical Industries, pure grade) were added to a 10 ml sample tube, and the solution was heated to 40 ° C. to prepare a solution (0.20 weight%).

  In a syringe, 0.5 ml of the resulting solution is placed on a silicon substrate (Miyoshi, resistance value: 0.001 to 0.004Ω, with a 200 nm silicon oxide film on the surface) of n-type n-type having a diameter of 2 inches in a syringe. The solution was packed and dropped through a 0.2 μm filter. It air-dried under room temperature (25 degreeC), and produced the thin film of di n-octyl benzothieno benzothiophene with a film thickness of 58 nm.

(Fabrication of organic thin film transistor)
By the same method as in Example 8, a bottom gate-top contact type p-type organic thin film transistor was produced.

The carrier mobility of holes was 0.14 cm ² / V · s, and the current on / off ratio was 2.2 × 10 ⁶ . The carrier mobility of holes after annealing at 150 ° C. for 15 minutes was 0.001 cm ² / V · s, and a significant decrease in performance due to heat treatment was observed. It was confirmed from microscopic observation that the organic semiconductor thin film was destroyed by heating.

  The organic thin film transistor according to the present invention can be expected to be applied as a semiconductor device material typified by an organic thin film transistor since it provides high carrier mobility and is excellent in heat resistance, solubility and oxidation resistance.

FIG. 5 is a view showing a structure based on the cross-sectional shape of the organic thin film transistor.

(A): bottom gate-top contact type organic thin film transistor (B): bottom gate-bottom contact type organic thin film transistor (C): top gate-top contact type organic thin film transistor (D): top gate-bottom contact type organic thin film transistor 1: Organic semiconductor layer 2: substrate 3: gate electrode 4: gate insulating layer 5: source electrode 6: drain electrode

Claims (7)

A heteroacene derivative represented by the following general formula (1).

(Here, the substituents R ^{1 to} R ⁶ are each independently hydrogen, halogen, an alkyl group having 1 to 14 carbon atoms, an acyl group having 1 to 14 carbon atoms, an aryl group having 4 to 16 carbon atoms, or carbon. an alkenyl group having 2 to 14, .T ¹ and T ² indicates an alkynyl group having 2 to 14 carbon atoms, represents a sulfur atom or a selenium atom independently. However, ^{T 1} and T ^2, at the same time sulfur There is nothing to do.) The substituents R ¹ and R ² are each independently hydrogen, halogen, an alkyl group having 1 to 14 carbon atoms, an acyl group having 1 to 14 carbon atoms, an aryl group having 4 to 16 carbon atoms, or 2 to 14 carbon atoms. The heteroacene derivative according to claim 1, wherein the heteroacene derivative is selected from the group consisting of an alkenyl group and an alkynyl group having 2 to 14 carbon atoms, and the substituents R ^{3 to} R ⁶ are hydrogen. The substituents R ¹ and R ² are each independently selected from the group consisting of hydrogen, an alkyl group having 1 to 14 carbon atoms, and an acyl group having 1 to 14 carbon atoms, and the substituents R ^{3 to} R ⁶ are hydrogen. The heteroacene derivative according to claim 1 or 2, characterized in that The substituents R ¹ and R ² are each independently an alkyl group having 1 to 14 carbon atoms, and the substituents R ^{3 to} R ⁶ are hydrogen. The heteroacene derivative described in (4). A solution for forming an organic semiconductor layer, which is obtained by dissolving the heteroacene derivative according to any one of claims 1 to 4 in a solvent. An organic semiconductor layer characterized by being obtained using the solution for forming an organic semiconductor layer according to claim 5. It is obtained using the organic-semiconductor layer of Claim 6, The organic thin-film transistor characterized by the above-mentioned.

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