JP5948772B2 - Dithienobenzodithiophene derivative composition and organic thin film transistor using the same - Google Patents

Description

  The present invention relates to a dithienobenzodithiophene derivative composition that can be developed into an electronic material such as an organic semiconductor material, and an organic thin film transistor using the same, and is particularly excellent in solubility in a solvent and has a high carrier mobility. The present invention relates to a novel dithienobenzodithiophene derivative composition that can be easily developed into an organic semiconductor material and the like, and an organic thin film transistor using the same.

  Organic semiconductor devices typified by organic thin film transistors have been attracting attention in recent years 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, and an electrode. Among them, the organic semiconductor layer responsible for charge carrier movement has a central role of the device. And since organic-semiconductor device performance is influenced by the carrier mobility of the organic material which comprises this organic-semiconductor layer, the appearance of the organic material which gives a high carrier mobility is desired.

  In addition, as a method for producing the organic semiconductor layer, a method such as a vacuum deposition method in which an organic material is vaporized under a high temperature vacuum, a coating method in which an organic material is dissolved in an appropriate solvent, and a solution thereof is applied is generally used. Known.

  In the coating method, the coating can be carried out using a printing technique without using high temperature and high vacuum conditions. Therefore, the coating method is an economically preferable process because it can greatly reduce the manufacturing cost of device fabrication by printing. And the organic-semiconductor material used for such an application | coating method has a low molecular type and a high molecular type, and it is preferable to have a solubility of 1.0 weight% or more. In general, a low molecular weight material having a high carrier mobility is preferable, but the types of low molecular weight organic semiconductor materials that have a solubility of 1.0% by weight or more and provide high mobility are extremely limited. Currently.

  Examples of the low molecular weight material include bis ((triisopropylsilyl) ethynyl) pentacene (see, for example, Non-Patent Document 1) and dialkyl-substituted benzothienobenzothiophene (highly soluble in a hydrocarbon solvent such as toluene). For example, refer to Patent Document 1), dihexyl dithienobenzodithiophene (for example, refer to Patent Document 2), and the like.

Re-published patent WO2008 / 047896 (see, for example, the claims) WO 2010/000670 (see, for example, claims)

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

However, bis ((triisopropylsilyl) ethynyl) pentacene described in Non-Patent Document 1 exhibits high solubility in non-polar solvents such as hexane, but when heated to 120 ° C. or higher, the thin film changes in quality and mobility increases. It had the subject that it falls from 1.0 cm < ² > / Vs to 0.2 cm < ² > / Vs. In addition, the dialkyl-substituted benzothienobenzothiophene described in Patent Document 1 can achieve a mobility of 1.0 cm ² / Vs or more by heat treatment at 100 ° C. or more as a spin coat film. When not applied, the temperature was as low as 0.08 to 0.17 cm ² / Vs, the melting point was as low as 120 to 130 ° C., and there was a problem in heat resistance. The dihexyl dithienobenzodithiophene proposed in Patent Document 2 shows a mobility of 0.112 cm ² / Vs by a drop cast method, but has a problem in solubility in a solvent at room temperature.

Further, in order to drive a display such as organic electroluminescence, the transistor needs to have a mobility of at least 0.5 cm ² / Vs, and there is a heating process such as electrode formation for device fabrication. However, there is no known organic semiconductor material having a heat resistance of 150 ° C. or higher and a solubility of 1.0% by weight or more at room temperature. Desired.

  Accordingly, an object of the present invention is to provide a novel organic semiconductor material that can be easily developed into an organic semiconductor material or the like because of its excellent solubility in a solvent.

  As a result of intensive studies to solve the above problems, the present inventors have found that a novel dithienobenzodithiophene derivative composition gives high carrier mobility and exhibits excellent solubility in a solvent. The invention has been completed.

  That is, the present invention provides a dithienobenzodithiophene derivative 99 to 80% by weight represented by the following general formula (1) and a dithienobenzodithiophene derivative 1 to 20% by weight represented by the following general formula (2). The present invention relates to a thienobenzodithiophene derivative composition and an organic thin film transistor using the same.

（ここで、置換基Ｒ^１及びＲ^２は同一又は異なって、ｎ−ペンチル基、ｎ−ヘキシル基、ｎ−ヘプチル基及びｎ−オクチル基からなる群より選択される置換基を示す。）

(Here, the substituents R ¹ and R ² are the same or different and represent a substituent selected from the group consisting of an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group.)

（ここで、置換基Ｒ^３及びＲ^４は同一又は異なって、エチル基、ｎ−プロピル基及びｎ−ブチル基からなる群より選択される置換基を示す。）
以下に、本発明を詳細に説明する。

(Here, the substituents R ³ and R ⁴ are the same or different and represent a substituent selected from the group consisting of an ethyl group, an n-propyl group, and an n-butyl group.)
The present invention is described in detail below.

  The dithienobenzodithiophene derivative composition of the present invention comprises 99 to 80% by weight of the dithienobenzodithiophene derivative represented by the general formula (1) and the dithienobenzodithiophene derivative 1 represented by the general formula (2). It is composed of ˜20% by weight, and is particularly excellent in handleability and solubility, and gives high carrier mobility, so that the dithienobenzodithiophene derivative represented by the general formula (1) is in the range of 99 to 90% by weight. % And a dithienobenzodithiophene derivative represented by the general formula (2) is preferably 1 to 10% by weight. Here, when the dithienobenzodithiophene derivative represented by the general formula (1) exceeds 99% by weight, the resulting composition has poor solubility in a solvent, and is obtained by a coating method (for example, an inkjet method). There is a problem in film formation. On the other hand, when the dithienobenzodithiophene derivative represented by the general formula (1) is less than 80% by weight, the resulting composition cannot give high carrier mobility.

The substituents R ¹ and R ² of the dithienobenzodithiophene derivative represented by the above general formula (1) constituting the dithienobenzodithiophene derivative composition of the present invention are the same or different, and an n-pentyl group, It is a substituent selected from the group consisting of an n-hexyl group, an n-heptyl group, and an n-octyl group. Among them, since it becomes a dithienobenzodithiophene derivative composition giving particularly high carrier mobility, it is preferably selected from the group consisting of n-pentyl group, n-hexyl group and n-heptyl group, The substituents R ¹ and R ² are the same and are preferably selected from the group consisting of an n-pentyl group, an n-hexyl group, and an n-heptyl group. Specific examples of the dithienobenzodithiophene derivative represented by the general formula (1) include di-n-pentyldithienobenzodithiophene, di-n-hexyldithienobenzodithiophene, and di-n-heptyldithienobenzodi. Examples include thiophene, n-pentyl-n-hexyldithienobenzodithiophene, n-pentyl-n-heptyldithienobenzodithiophene, and among others, di-n-pentyldithienobenzodithiophene, di-n-hexyl. Dithienobenzodithiophene and di-n-heptyldithienobenzodithiophene are preferable.

The substituents R ³ and R ⁴ of the dithienobenzodithiophene derivative represented by the general formula (2) constituting the dithienobenzodithiophene derivative composition of the present invention are the same or different, and may be an ethyl group, n- It is a substituent selected from the group consisting of a propyl group and an n-butyl group. Among them, an n-propyl group and / or an n-butyl group is preferable because a dithienobenzodithiophene derivative composition giving particularly high solubility is obtained. Specific examples of the dithienobenzodithiophene derivative represented by the general formula (2) include di-n-propyldithienobenzodithiophene, di-n-butyldithienobenzodithiophene, and n-propyl-n-butyldi. Examples include thienobenzodithiophene, among which di-n-propyldithienobenzodithiophene and di-n-butyldithienobenzodithiophene are preferable.

  Specific preferred examples of the dithienobenzodithiophene derivative represented by the general formula (1) and the dithienobenzodithiophene derivative represented by the general formula (2) constituting the dithienobenzodithiophene derivative composition of the present invention Examples of combinations include high carrier mobility and high solubility in a solvent. For example, di-n-hexyldithienobenzodithiophene, di-n-butyldithienobenzodithiophene, and di-n-pentyldithienobenzodithiophene. And di-n-butyldithienobenzodithiophene, di-n-heptyldithienobenzodithiophene and di-n-butyldithienobenzodithiophene, di-n-hexyldithienobenzodithiophene and di-n-propyldithienobenzodithiophene Etc. are combinations.

  The dithienobenzodithiophene derivative composition of the present invention is suitable for film formation by a coating method, a drop cast method, particularly an ink jet method, and therefore exhibits a solubility of 1% by weight or more with respect to a solvent at room temperature. Preferably, the solvent at that time is, for example, an aromatic hydrocarbon solvent such as toluene, xylene, mesitylene, biphenyl, ethylbenzene, hexylbenzene, octylbenzene; hexane, heptane, octane, decane, dodecane, tetradecane, etc. Aliphatic hydrocarbon solvents; halogen solvents such as o-dichlorobenzene, chlorobenzene, trichlorobenzene, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, chloroform, dichloromethane; tetrahydrofuran (hereinafter referred to as THF). ), Aether such as dioxane Solvent, ester solvents such as ethyl acetate and γ-butyrolactone; amide solvents such as N, N-dimethylformamide and N-methyl-2-pyrrolidone (hereinafter referred to as NMP); Since a solution having a boiling point can be obtained, an aromatic hydrocarbon solvent having 7 to 13 carbon atoms such as toluene, xylene, and ethylbenzene is preferable, and toluene and xylene are particularly preferable. Here, room temperature is generally referred to as room temperature, and examples thereof include a temperature of 20 to 24 ° C.

  When preparing a solution of the dithienobenzodithiophene derivative composition of the present invention, the dithienobenzodithiophene derivative composition and the above-mentioned solvent are mixed, heated and stirred, and listed above. The dithienobenzodithiophene derivative represented by the general formula (1) and the dithienobenzodithiophene derivative represented by (2) are mixed, heated and stirred. The temperature at the time of heating and stirring is preferably 30 to 150 ° C, particularly preferably 40 to 100 ° C. The concentration of the dithienobenzodithiophene derivative during stirring is preferably 0.1 to 10.0% by weight.

  As a method for producing the dithienobenzodithiophene derivative represented by the above general formula (1) and the dithienobenzodithiophene derivative represented by the above general formula (2) constituting the dithienobenzodithiophene derivative composition of the present invention, As long as it is possible to produce these dithienobenzodithiophene derivatives, any production method can be used, and among them, it is particularly easy to produce a high-purity dithienobenzodithiophene derivative. Therefore, it is preferable to produce these dithienobenzodithiophene derivatives by a production method that includes at least the following steps (A) to (D).

  Step (A): 1,4-di (3-bromo-2-thienyl) -2 with 3-bromothiophene-2-zinc derivative and 1,4-dibromo-2,5-difluorobenzene in the presence of a palladium catalyst , 5-Difluorobenzene production step.

  Step (B): Dithieno by intramolecular cyclization of 1,4-di (3-bromo-2-thienyl) -2,5-difluorobenzene obtained in Step (A) in the presence of an alkali metal sulfide. A process for producing benzodithiophene.

  Step (C): A diacylate of dithienobenzodithiophene is produced by Friedel-Crafts acylation reaction of dithienobenzodithiophene obtained in step (B) and an acyl chloride compound in the presence of aluminum chloride as a catalyst. Process.

  (D) Process; The process of using the diacyl body of the dithienobenzodithiophene obtained by the (C) process for a reductive reaction, and manufacturing a dithienobenzodithiophene derivative.

  And the more specific manufacturing scheme of a preferable manufacturing method is shown below.

ここで、（Ａ）工程は、パラジウム触媒の存在下、３−ブロモチオフェン−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−ブロモ−２−チエニル）−２，５−ジフルオロベンゼンを製造する工程である。

Here, in the step (A), 1,4-di (3- (3) is obtained by cross-coupling of a 3-bromothiophene-2-zinc derivative and 1,4-dibromo-2,5-difluorobenzene in the presence of a palladium catalyst. This is a process for producing bromo-2-thienyl) -2,5-difluorobenzene.

  The 3-bromothiophene-2-zinc derivative is prepared by using an organometallic reagent such as ethylmagnesium chloride, isopropylmagnesium bromide, phenylmagnesium chloride, etc., replacing bromine at the 2-position of 2,3-dibromothiophene with magnesium halide, and then chlorinating. It can be prepared by exchanging metal with zinc. It is also possible to prepare a Grignard reagent of 2,3-dibromothiophene using magnesium metal instead of the organometallic reagent. The conditions for preparing the 2,3-dibromothiophene Grignard reagent can be carried out, for example, in a solvent such as THF or diethyl ether within a temperature range of -80 ° C to 70 ° C. A 3-bromothiophene-2-zinc derivative can be prepared by reacting the Grignard reagent solution with zinc chloride. Zinc chloride may be used as it is, or it may be THF or diethyl ether solution. As temperature, it can implement within the range of -80 degreeC-30 degreeC.

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

  Step (B) is a step of producing dithienobenzodithiophene by intramolecular cyclization of 1,4-di (3-bromo-2-thienyl) -2,5-difluorobenzene in the presence of an alkali metal sulfide. It is.

  Examples of the alkali metal sulfide include sodium sulfide, potassium sulfide, lithium sulfide, rubidium sulfide, and hydrates thereof. Examples of the intramolecular cyclization reaction include NMP, N, N-dimethylformamide, and the like. In the temperature range of 80 ° C. to 200 ° C.

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

  Examples of the acyl chloride compound include acetyl chloride, propionyl chloride, butyryl chloride, pentanoyl chloride, hexanoyl chloride, heptanoyl chloride, octanoyl chloride and the like. The Friedel-Crafts acylation reaction can be carried out in a temperature range of 0 ° C. to 40 ° C. in a solvent such as dichloromethane, 1,2-dichloroethane, toluene and the like.

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

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

  Further, the produced dithienobenzodithiophene derivative can be purified by subjecting it to column chromatography or the like. As the separating agent at that time, for example, silica gel, alumina, as a solvent, hexane, heptane, toluene, xylene , Chloroform, dichloromethane and the like.

  Further, the produced dithienobenzodithiophene derivative may be further purified by recrystallization, and the number of recrystallizations is preferably 2 to 5 times. 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 dithienobenzodithiophene derivative is prepared by heating (the concentration of the solution is preferably in the range of 0.01 to 10.0% by weight, and 0.05 to 5.0% by weight). The crystal of the dithienobenzodithiophene derivative is precipitated and isolated by cooling the solution, and the final cooling temperature during the isolation is in the range of −20 ° C. to 40 ° C. It is preferable that it exists in. In addition, when measuring purity, it is possible to analyze by liquid chromatography.

  The dithienobenzodithiophene derivative composition of the present invention has excellent properties as an organic semiconductor material because it provides high carrier mobility, and has high solubility in a solvent. In particular, an organic semiconductor layer can be formed easily and efficiently by a method such as an inkjet method.

  The organic thin film transistor is obtained by laminating an organic semiconductor layer provided with a source electrode and a drain electrode on a substrate and a gate electrode through an insulating layer, and the dithienobenzo of the present invention is formed on the organic semiconductor layer. By using an organic semiconductor layer made of a dithiophene derivative composition, an organic thin film transistor can be obtained.

  FIG. 1 shows a structure of a general organic thin film transistor by a sectional shape. 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 the dithienobenzodithiophene derivative composition of the present invention The organic semiconductor layer formed can be applied to any organic thin film transistor.

  Examples of the substrate include polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate, polymethyl acrylate, polyethylene, polypropylene, polystyrene, cyclic polyolefin, polyimide, polycarbonate, polyvinyl phenol, polyvinyl alcohol, poly (diisopropyl fumarate), poly ( (Diethyl fumarate), poly (diisopropyl maleate), polyethersulfone, polyphenylene sulfide, cellulose triacetate and other plastic substrates; glass, quartz, aluminum oxide, silicon, highly doped silicon, silicon oxide, tantalum dioxide, tantalum pentoxide, indium Inorganic material substrates such as tin oxide; Metal substrates such as gold, copper, chromium, titanium, aluminum, etc. Can. When highly doped silicon is used for the substrate, the substrate can also serve as the gate electrode.

  Examples of the gate electrode include aluminum, gold, silver, copper, highly doped silicon, tin oxide, indium oxide, indium tin oxide, inorganic materials such as chromium, titanium, tantalum, graphene, and carbon nanotube; doped conductivity An organic material such as a polymer (for example, PEDOT-PSS) can be used.

  Examples of the gate insulating layer include inorganic materials such as silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, titanium oxide, tantalum dioxide, tantalum pentoxide, indium tin oxide, tin oxide, vanadium oxide, barium titanate, and bismuth titanate. Material substrate: Plastic materials such as polymethyl methacrylate, polymethyl acrylate, polyimide, polycarbonate, polyvinyl phenol, polyvinyl alcohol, poly (diisopropyl fumarate), poly (diethyl fumarate), polyethylene terephthalate, polyethylene naphthalate, polyethersulfone Can be mentioned. The surfaces of these gate insulating layers are, for example, octadecyltrichlorosilane, decyltrichlorosilane, decyltrimethoxysilane, octyltrichlorosilane, octadecyltrimethoxysilane, β-phenethyltrichlorosilane, β-phenethyltrimethoxysilane, phenyltrichlorosilane. Silanes such as phenyltrimethoxysilane and phenyltriethoxysilane; and those modified with silylamines such as hexamethyldisilazane can also be used. In general, the surface treatment of the gate insulating layer is preferable in order to increase the crystal grain size and molecular orientation of the organic semiconductor material, and to improve the carrier mobility and current on / off ratio, and to lower the threshold voltage. Results are obtained.

  As a material of the source electrode and the drain electrode, the same material as that of the gate electrode can be used, and the material may be the same as or different from the material of the gate electrode, or different materials may be stacked. In order to increase the carrier injection efficiency, surface treatment can be performed on these electrode materials. Examples thereof include benzene thiol and pentafluorobenzene thiol.

  Further, the dithienobenzodithiophene derivative composition of the present invention may be one in which a polymer binder coexists. Examples of the polymer binder include polystyrene, poly α-methylstyrene, polyethylene naphthalate, polymethyl methacrylate, and the like. It can mention as a suitable thing. The amount of the polymer binder used is preferably 1 to 1000% by weight based on the dithienobenzodithiophene derivative composition.

  When the organic semiconductor layer is an organic semiconductor layer comprising the dithienobenzodithiophene derivative composition of the present invention, for example, a drop casting method such as spin coating, cast coating, or ink jet; blade coating; dip coating, screen It is possible to use a method such as printing, gravure printing, etc., and among them, it is possible to easily and efficiently form an organic semiconductor layer, so that it may be a drop casting method such as spin coating, cast coating, inkjet, etc. Particularly preferred is an ink jet. Moreover, there is no restriction | limiting in the film thickness of the organic-semiconductor layer in that case, Preferably they are 1 nm-1 micrometer, Most preferably, they are 10 nm-300 nm.

  The organic semiconductor layer containing the dithienobenzodithiophene derivative composition of the present invention can be annealed at 40 to 150 ° C. after coating and drying.

  The dithienobenzodithiophene derivative composition of the present invention is used for an organic semiconductor layer of a transistor such as an electronic paper, an organic EL display, a liquid crystal display, and an IC tag (RFID tag); an organic EL display material; an organic semiconductor laser material; Thin film solar cell materials; can be used for electronic materials such as photonic crystal materials.

  The novel dithienobenzodithiophene derivative composition of the present invention provides a high carrier mobility and is excellent in solubility in a solvent, so that an organic semiconductor thin film can be easily produced. As a semiconductor device material, the effect is extremely high.

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

For the identification of the product, ¹ H-NMR spectrum and mass spectrum were used. The ¹ H-NMR spectrum was measured using JEOL GSX-270WB (270 MHz) manufactured by JEOL. Mass spectrum (MS) was measured by electron impact (EI) method (70 electron volts) using JEOL JMS-700 (trade name) manufactured by JEOL directly with the sample introduced.

  Confirmation of the progress of the reaction was performed by thin layer chromatography, gas chromatography (GC) and gas chromatography-mass spectrum (GCMS) analysis.

Gas chromatography analyzer; manufactured by Shimadzu Corporation (trade name) GC14B
Column; 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; J & W Scientific (trade name) DB-1, 30 m.

Liquid chromatographic analysis was used to determine the purity of the dithienobenzodithiophene derivative.
Device: manufactured by Tosoh (controller; PX-8020, pump; CCPM-II, degasser; SD-8022)
Column: manufactured by Tosoh (trade name) ODS-100V, 5 μm, 4.6 mm × 250 mm
Column temperature: 23 ° C
Eluent: dichloromethane: acetonitrile = 4: 6 (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-bromo-2-thienyl) -2,5-difluorobenzene (step (A)))
Under a nitrogen atmosphere, 1.9 ml (3.8 mmol) of a THF solution of ethylmagnesium chloride (manufactured by Sigma-Aldrich, 2.0 mol / l) and 10 ml of THF were added to a 100 ml Schlenk reaction vessel. The mixture was cooled to −75 ° C., and 873 mg (3.61 mmol) of 2,3-dibromothiophene (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise. After aging at 15 ° C. for 20 minutes, 491 mg (3.60 mmol) of zinc chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was added. After 15 minutes of reaction at 15 ° C., the mixture was aged at 26 ° C. for 10 minutes. To the obtained white slurry (3-bromo-2-thienyl-2-zinc chloride), 272 mg (1.00 mmol) of 1,4-dibromo-2,5-difluorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.) as a catalyst Tetrakis (triphenylphosphine) palladium (manufactured by Tokyo Chemical Industry Co., Ltd.) 23.1 mg (0.0200 mmol, 2.00 mol% based on 1,4-dibromo-2,5-difluorobenzene) was added. After carrying out the reaction for 3 hours at 60 ° C., the vessel was cooled with water and the reaction was stopped by adding 3 ml of 3N hydrochloric acid. Extraction was performed with toluene, and the organic phase was washed with brine and dried over anhydrous sodium sulfate. The residue obtained by concentration under reduced pressure was filtered through silica gel column chromatography (toluene). The residue obtained by concentrating the filtrate was washed with hexane, recrystallized and purified from heptane / toluene = 2/1, and diluted with 1,4-di (3-bromo-2-thienyl) -2,5-difluorobenzene. 262 mg of a yellow solid was obtained (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, 2H).
MS m / z: 436 (M ^<+> , 100%), 276 (M ^<+ > ^- 2Br, 13).

Synthesis example 2
(Synthesis of dithienobenzodithiophene (step (B)))
Under a nitrogen atmosphere, 10 ml of NMP and 240 mg (1.00 mmol) of sodium sulfide nonahydrate (manufactured by Wako Pure Chemical Industries, Ltd.) were added to a 100 ml Schlenk reaction vessel. This mixture was heated at 170 ° C. for 2 hours, and water was distilled out of the system. The obtained mixture was cooled to room temperature, 200 mg (0.458 mmol) of 1,4-di (3-bromo-2-thienyl) -2,5-difluorobenzene was added, and the mixture was heated at 170 ° C. for 6 hours. The resulting reaction mixture was cooled to room temperature. After adding toluene and water, the phases were separated, and the organic phase was washed with water twice and dried over anhydrous sodium sulfate. After concentration under reduced pressure, the resulting residue was washed twice with hexane to obtain 95 mg of a light yellow solid of dithienobenzodithiophene (yield 69%).
¹ H-NMR (CDCl ₃ , 60 ° C.): δ = 8.28 (s, 2H), 7.51 (d, J = 5.2 Hz, 2H), 7.30 (d, J = 5.2 Hz, 2H).
MS m / z: 302 (M ^<+> , 100%), 270 (M ^<+> -S, 5), 151 (M ^<+ > / 2, 10).

Synthesis example 3
(Synthesis of di-n-hexanoyldithienobenzodithiophene (step (C)))
To a 100 ml Schlenk reaction vessel were added 86.8 mg (0.286 mmol) of dithienobenzodithiophene and 14 ml of dichloromethane. This mixture was ice-cooled, and 134 mg (1.00 mmol) of aluminum chloride (manufactured by Wako Pure Chemical Industries) and 115 mg (0.854 mmol) of hexanoyl chloride (manufactured by Wako Pure Chemical Industries) were added. The resulting mixture was stirred at room temperature for 30 hours, then ice-cooled and water was added to stop the reaction. Hexane was added to the resulting slurry mixture for phase separation. After removing the supernatant liquid of the obtained yellow slurry of the organic phase, methanol was added to the residue, and the mixture was stirred and allowed to stand. The residue obtained by removing the supernatant was dried under reduced pressure, and 128 mg of a yellow solid of di-n-hexanoyldithienobenzodithiophene was obtained (yield 90%).
¹ H-NMR (heavy benzene, 80 ° C.): δ = 7.73 (s, 2H), 7.26 (s, 2H), 2.58 (t, J = 7.2 Hz, 4H), 1.71 (M, 4H), 1.28 (m, 8H), 0.86 (t, J = 7.0 Hz, 6H).
_{^{MS m / z: 498 (M}} +, 100%), 442 (M + -C 4 H 9 +1,46), 427 (M + -C 5 H 11, 13).

Synthesis example 4
(Synthesis of di-n-hexyldithienobenzodithiophene (dithienobenzodithiophene derivative represented by the general formula (1)) (step (D)))
Under a nitrogen atmosphere, in a 100 ml Schlenk reaction vessel, 120 mg (0.241 mmol) of di-n-hexanoyldithienobenzodithiophene, 177 mg (1.33 mmol) of aluminum chloride (Wako Pure Chemical Industries), sodium borohydride (Wako Pure Chemical) 84.0 mg (2.22 mmol) and 6 ml of THF were added. The mixture was stirred for 3 hours under reflux with heating, cooled with water, and water was added to stop the reaction. Extracted with toluene, the organic phase was washed with water and dried over anhydrous sodium sulfate. Concentrated under reduced pressure, the resulting residue was filtered through a silica gel column (toluene), concentrated under reduced pressure, and the resulting residue was washed with hexane and further recrystallized and purified four times from toluene (pure grade manufactured by Wako Pure Chemical Industries). 39.7 mg of pale yellow scaly crystals of n-hexyldithienobenzodithiophene were obtained (yield 35%).

The purity of the obtained di-n-hexyldithienobenzodithiophene was 99.55% by liquid chromatography.
¹ H-NMR (CDCl ₃ , 21 ° C.): δ = 8.17 (s, 2H), 7.00 (s, 2H), 2.97 (t, J = 7.2 Hz, 4H), 1.78 (M, 4H), 1.28 (m, 12H), 0.88 (t, J = 7.0 Hz, 6H).
_{^{MS m / z: 470 (M}} +, 100%), 399 (M + -C 5 H 11, 57), 328 (M + -2C 5 H 11, 47).
Melting point: 190.2-190.4 ° C.

Synthesis example 5
(Synthesis of di-n-pentanoyldithienobenzodithiophene (step (C)))
The same procedure as in Synthesis Example 3 was repeated except that pentanoyl chloride (manufactured by Wako Pure Chemical Industries) was used instead of hexanoyl chloride (manufactured by Wako Pure Chemical Industries) of Synthesis Example 3, and di-n-pentanoyl dithienobenzo was used. A yellow solid of dithiophene was obtained (yield 92%).
¹ H-NMR (heavy benzene, 80 ° C.): δ = 7.73 (s, 2H), 7.26 (s, 2H), 2.58 (t, J = 7.2 Hz, 4H), 1.71 (M, 4H), 1.35 (m, 4H), 0.90 (t, J = 7.0 Hz, 6H).
_{^{MS m / z: 470 (M}} +, 100%), 428 (M + -C 3 H 7 +1,49), 413 (M + -C 4 H 9, 20).

Synthesis Example 6
(Synthesis of di-n-pentyldithienobenzodithiophene (dithienobenzodithiophene derivative represented by the general formula (1)) (step (D)))
In place of di-n-hexanoyldithienobenzodithiophene in Synthesis Example 4, the same operation as in Synthesis Example 4 was repeated except that di-n-pentanoyldithienobenzodithiophene obtained in Synthesis Example 5 was used. Pale yellow scaly crystals of di-n-pentyldithienobenzodithiophene were obtained (35% yield).

The purity of the obtained di-n-pentyldithienobenzodithiophene was 99.48% by liquid chromatography.
¹ H-NMR (CDCl ₃ , 21 ° C.): δ = 8.16 (s, 2H), 7.00 (s, 2H), 2.94 (brs, 4H), 1.78 (m, 4H), 1.36 (m, 8H), 0.92 (t, J = 7.0 Hz, 6H).
_{^{MS m / z: 442 (M}} +, 100%), 385 (M + -C 4 H 9, 51), 328 (M + -2C 4 H 9, 44).
Melting point: 197.9-198.3 ° C.

Synthesis example 7
(Synthesis of di-n-butanoyldithienobenzodithiophene (step (C)))
A procedure similar to that in Synthesis Example 3 was repeated except that butyryl chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of hexanoyl chloride in Synthesis Example 3 to obtain a yellow solid of di-n-butanoyldithienobenzodithiophene. (93% yield).
¹ H-NMR (heavy benzene, 80 ° C.): δ = 7.78 (s, 2H), 7.25 (s, 2H), 2.55 (t, J = 7.2 Hz, 4H), 1.73 (M, 4H), 0.92 (t, J = 7.0 Hz, 6H).
_{^{MS m / z: 442 (M}} +, 100%), 414 (M + -C 2 H 5 +1,51), 399 (M + -C 3 H 7, 18).

Synthesis Example 8
(Synthesis of di-n-butyldithienobenzodithiophene (dithienobenzodithiophene derivative represented by the general formula (2)) (step (D)))
The same procedure as in Synthesis Example 4 was repeated except that di-n-butanoyldithienobenzodithiophene obtained in Synthesis Example 7 was used instead of di-n-hexanoyldithienobenzodithiophene in Synthesis Example 4. A pale yellow crystal of di-n-butyldithienobenzodithiophene was obtained (yield 36%).

The purity of the obtained di-n-butyldithienobenzodithiophene was 99.44% by liquid chromatography.
¹ H-NMR (CDCl ₃ , 21 ° C.): δ = 8.16 (s, 2H), 7.00 (s, 2H), 2.95 (t, J = 7.2 Hz, 4H), 1.73 (M, 4H), 1.46 (m, 4H), 0.97 (t, J = 7.0 Hz, 6H).
_{^{MS m / z: 414 (M}} +, 100%), 371 (M + -C 3 H 7, 61), 328 (M + -2C 3 H 7, 49).
Melting point: 205.0-205.2 ° C.

Synthesis Example 9
(Synthesis of di-n-propionyldithienobenzodithiophene (step (C)))
The same procedure as in Synthetic Example 3 was repeated except that proonyl chloride was used instead of hexanoyl chloride in Synthetic Example 3 to obtain di-n-propionyl dithienobenzodithiophene solid.

Synthesis Example 10
(Synthesis of di-n-bromodithienobenzodithiophene (dithienobenzodithiophene derivative represented by the general formula (2)) (step (D)))
Instead of di-n-hexanoyldithienobenzodithiophene in Synthesis Example 4, the same operation as in Synthesis Example 4 was repeated except that di-n-propionyldithienobenzodithiophene obtained in Synthesis Example 9 was used. Crystals of di-n-propyldithienobenzodithiophene were obtained.

Example 1
Di-n-hexyldithienobenzodithiophene 14.7 mg obtained in Synthesis Example 4 and di-n-butyldithienobenzodithiophene 0.78 mg obtained in Synthesis Example 8 were mixed to obtain a dithienobenzodithiophene derivative composition. The product (dithienobenzodithiophene derivative represented by the general formula (1) / dithienobenzodithiophene derivative represented by the general formula (2) = 95 wt% / 5 wt%) was obtained. The total amount of the dithienobenzodithiophene derivative composition and 1.39 g of toluene (Pure Grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed, dissolved by heating at 50 ° C., and then allowed to stand at room temperature (23 ° C.) for 12 hours. Since no crystal precipitation was observed and the solution state was 1.17% by weight, it was confirmed that the material was suitable for film formation by inkjet.

  Further, 17.5 mg of di-n-hexyldithienobenzodithiophene (95% by weight of a dithienobenzodithiophene derivative represented by the general formula (1)), 0.92 mg of di-n-butyldithienobenzodithiophene (general formula ( 2) dithioenobenzodithiophene derivative (5% by weight) and 9.10 g of toluene (pure grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and heated to 40 ° C. to prepare a dithienobenzodithiophene derivative composition solution. (0.20% by weight).

  Then, the obtained dithienobenzodidioxide is obtained on an n-type highly doped silicon substrate (manufactured by Semitech, resistance value: 0.001 to 0.004Ω, with a silicon oxide film of 200 nm on the surface) having a diameter of 2 inches in air. A syringe was filled with 0.5 ml of the thiophene derivative composition solution, and the solution passed through a 0.2 μm filter was drop-cast. A dithienobenzodithiophene derivative composition comprising 95% by weight of di-n-hexyldithienobenzodithiophene and 5% by weight of di-n-butyldithienobenzodithiophene having a film thickness of 58 nm, which is naturally dried at room temperature (23 ° C.) A thin film was prepared.

  A shadow mask having a channel length of 45 μm and a channel width of 1500 μm was placed on the organic thin film, and gold was vacuum-deposited to form an electrode. Thus, a bottom gate-top contact type p-type organic thin film transistor was produced.

The electrical properties of the produced organic thin film transistor were measured in the air using a semiconductor parameter analyzer (manufactured by Agilent Technologies, (trade name) B1500A) at a drain voltage (Vd = -50V) and a gate voltage (Vg) of +10 to -60V. And the transfer characteristics were evaluated. The hole carrier mobility was 1.14 cm ² / V · s, and the current on / off ratio was 5.6 × 10 ⁷ .

Example 2
18.5 mg of di-n-pentyldithienobenzodithiophene obtained in Synthesis Example 6 and 0.97 mg of di-n-butyldithienobenzodithiophene obtained in Synthesis Example 8 were mixed to obtain a dithienobenzodithiophene derivative composition. The product (dithienobenzodithiophene derivative represented by the general formula (1) / dithienobenzodithiophene derivative represented by the general formula (2) = 95 wt% / 5 wt%) was obtained. Then, the total amount of the dithienobenzodithiophene derivative composition and 1.73 g of toluene (Pure Grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed, heated and dissolved at 50 ° C., and then allowed to stand at room temperature (23 ° C.) for 12 hours. Since no crystal precipitation was observed and the solution state of 1.11% by weight was maintained, it was confirmed that the material was suitable for film formation by inkjet.

  Further, 17.1 mg of di-n-pentyldithienobenzodithiophene (95% by weight of dithienobenzodithiophene derivative represented by the general formula (1)), 0.90 mg of di-n-butyldithienobenzodithiophene (general formula ( The dithienobenzodithiophene derivative represented by 2) (5% by weight) and 9.00 g of toluene (Pure Grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and heated to 40 ° C. to prepare a solution (0.20% by weight).

Then, a bottom gate-top contact type p-type organic thin film transistor was fabricated by the same method as in Example 1. The hole carrier mobility was 0.89 cm ² / V · s, and the current on / off ratio was 2.1 × 10 ⁷ .

Example 3
Din-pentyldithienobenzodithiophene 9.54 mg obtained in Synthesis Example 6 and din-butyldithienobenzodithiophene 1.06 mg obtained in Synthesis Example 8 were mixed to obtain a dithienobenzodithiophene derivative composition. The product (dithienobenzodithiophene derivative represented by the general formula (1) / dithienobenzodithiophene derivative represented by the general formula (2) = 90% by weight / 10% by weight) was obtained. Then, the total amount of the dithienobenzodithiophene derivative composition and 0.927 g of m-xylene (Sigma-Aldrich dehydrated grade) were mixed, dissolved by heating at 50 ° C., and then allowed to stand at room temperature (23 ° C.) for 12 hours. . Since no crystal precipitation was observed and the solution state was 1.13 wt%, it was confirmed that the material was suitable for film formation by inkjet.

  Further, di-n-pentyldithienobenzodithiophene 6.89 mg (dithienobenzodithiophene derivative represented by the general formula (1) 90% by weight), di-n-butyldithienobenzodithiophene 0.77 mg (general formula ( The dithienobenzodithiophene derivative represented by 2) (10% by weight) and 3.83 g of toluene (pure grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and heated to 40 ° C. to prepare a solution (0.20% by weight).

Then, a bottom gate-top contact type p-type organic thin film transistor was fabricated by the same method as in Example 1. The hole carrier mobility was 0.72 cm ² / V · s, and the current on / off ratio was 1.9 × 10 ⁷ .

Example 4
Din-pentyldithienobenzodithiophene 9.01 mg obtained in Synthesis Example 6 and di-n-butyldithienobenzodithiophene 1.59 mg obtained in Synthesis Example 8 were mixed to obtain a dithienobenzodithiophene derivative composition. The product (dithienobenzodithiophene derivative represented by the general formula (1) / dithienobenzodithiophene derivative represented by the general formula (2) = 85 wt% / 15 wt%) was obtained. Then, 0.913 g of the total amount of the dithienobenzodithiophene derivative composition and 0.913 g of toluene (dehydrated grade manufactured by Sigma-Aldrich) were mixed, heated and dissolved at 50 ° C., and then allowed to stand at room temperature (23 ° C.) for 12 hours. Since no crystal precipitation was observed and the solution state was 1.15% by weight, it was confirmed that the material was suitable for film formation by inkjet.

  In addition, 6.51 mg of di-n-pentyldithienobenzodithiophene (85% by weight of a dithienobenzodithiophene derivative represented by the general formula (1)), 1.15 mg of di-n-butyldithienobenzodithiophene (general formula ( The dithienobenzodithiophene derivative represented by 2) (15% by weight) and 3.83 g of toluene (Pure grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and heated to 40 ° C. to prepare a solution (0.20% by weight).

Then, a bottom gate-top contact type p-type organic thin film transistor was fabricated by the same method as in Example 1. The hole carrier mobility was 0.70 cm ² / V · s, and the current on / off ratio was 1.7 × 10 ⁷ .

Example 5
Di n-hexyl dithienobenzodithiophene 9.54 mg obtained in Synthesis Example 4 and di n-propyldithienobenzodithiophene 1.06 mg obtained in Synthesis Example 10 were mixed to obtain a dithienobenzodithiophene derivative composition. The product (dithienobenzodithiophene derivative represented by the general formula (1) / dithienobenzodithiophene derivative represented by the general formula (2) = 90% by weight / 10% by weight) was obtained. Then, the total amount of the dithienobenzodithiophene derivative composition and 0.927 g of toluene (dehydrated grade manufactured by Sigma-Aldrich) were mixed, dissolved by heating at 50 ° C., and then allowed to stand at room temperature (23 ° C.) for 12 hours. Since no crystal precipitation was observed and the solution state was 1.13 wt%, it was confirmed that the material was suitable for film formation by inkjet.

  In addition, di-n-hexyldithienobenzodithiophene 6.89 mg (dithienobenzodithiophene derivative represented by general formula (1) 90% by weight), di-n-propyldithienobenzodithiophene 0.77 mg (general formula (1) The dithienobenzodithiophene derivative represented by 2) (10% by weight) and 3.83 g of toluene (pure grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and heated to 40 ° C. to prepare a solution (0.20% by weight).

Then, a bottom gate-top contact type p-type organic thin film transistor was fabricated by the same method as in Example 1. The hole carrier mobility was 1.07 cm ² / V · s, and the current on / off ratio was 4.5 × 10 ⁷ .

Example 6
The di-n-pentyldithienobenzodithiophene 9.01 mg obtained in Synthesis Example 6 and the di-n-propyldithienobenzodithiophene 1.59 mg obtained in Synthesis Example 10 were mixed to obtain a dithienobenzodithiophene derivative composition. The product (dithienobenzodithiophene derivative represented by the general formula (1) / dithienobenzodithiophene derivative represented by the general formula (2) = 85 wt% / 15 wt%) was obtained. Then, 0.913 g of the total amount of the dithienobenzodithiophene derivative composition and 0.913 g of toluene (dehydrated grade manufactured by Sigma-Aldrich) were mixed, heated and dissolved at 50 ° C., and then allowed to stand at room temperature (23 ° C.) for 12 hours. Since no crystal precipitation was observed and the solution state was 1.15% by weight, it was confirmed that the material was suitable for film formation by inkjet.

  Further, 6.51 mg of di-n-pentyldithienobenzodithiophene (85% by weight of dithienobenzodithiophene derivative represented by the general formula (1)), 1.15 mg of di-n-propyldithienobenzodithiophene (general formula ( The dithienobenzodithiophene derivative represented by 2) (15% by weight) and 3.83 g of toluene (Pure grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and heated to 40 ° C. to prepare a solution (0.20% by weight).

Then, a bottom gate-top contact type p-type organic thin film transistor was fabricated by the same method as in Example 1. The hole carrier mobility was 0.69 cm ² / V · s, and the current on / off ratio was 1.71 × 10 ⁷ .

Comparative Example 1
15.5 mg of di-n-hexyldithienobenzodithiophene obtained in Synthesis Example 4 and 1.40 g of toluene (pure grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed, dissolved by heating at 50 ° C, and then at room temperature (23 ° C) For 3 hours. Since scale-like crystals were precipitated, it was filtered. When the solution portion was concentrated, 8.77 mg was recovered. Accordingly, the solution concentration of di-n-hexyldithienobenzodithiophene at room temperature was 0.62% by weight. Di-n-hexyldithienobenzodithiophene was a compound not suitable for ink-jet film formation because it did not show a solubility of 1.0% by weight or more.

  Further, 0.88 mg of the di-n-hexyldithienobenzodithiophene and 435 mg of toluene (Pure Grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and heated to 50 ° C. to prepare a solution (0.20% by weight).

Then, a bottom gate-top contact type p-type organic thin film transistor was fabricated by the same method as in Example 1. The hole carrier mobility was 1.28 cm ² / V · s, and the current on / off ratio was 5.1 × 10 ⁷ .

Comparative Example 2
16.3 mg of di-n-pentycyldithienobenzodithiophene obtained in Synthesis Example 6 and 1.54 g of toluene (pure grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed, dissolved by heating at 50 ° C, and then at room temperature (23 ° C ) For 4 hours. Since scale-like crystals were precipitated, it was filtered. When the solution portion was concentrated, 10.3 mg was recovered. Accordingly, the solution concentration of di-n-pentycyldithienobenzodithiophene at room temperature was 0.66% by weight. Di-n-pentycyldithienobenzodithiophene is a compound that is not suitable for film formation by ink jet because it does not have a solubility of 1.0% by weight or more.

  In addition, 0.84 mg of the di-n-pentycyldithienobenzodithiophene and 421 mg of toluene (Pure Grade manufactured by Wako Pure Chemical Industries, Ltd.) were added, and heated to 50 ° C. to prepare a solution (0.20% by weight).

Then, a bottom gate-top contact type p-type organic thin film transistor was fabricated by the same method as in Example 1. The hole carrier mobility was 0.94 cm ² / V · s, and the current on / off ratio was 2.5 × 10 ⁷ .

Comparative Example 3
21.4 mg of di-n-butycyldithienobenzodithiophene obtained in Synthesis Example 8 and 1.53 g of toluene (Pure Grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed, dissolved by heating at 40 ° C, and then at room temperature (23 ° C ) For 12 hours. No crystal precipitation was observed, and the solution state of 1.38% by weight was maintained. Since di-n-butycyldithienobenzodithiophene has a solubility of 1.0% by weight or more, it was confirmed that it is a material suitable for film formation by inkjet.

  Further, 0.85 mg of the di-n-butyldithienobenzodithiophene and 425 mg of toluene (Pure grade manufactured by Wako Pure Chemical Industries, Ltd.) were added and heated to 50 ° C. to prepare a solution (0.20% by weight).

Then, a bottom gate-top contact type p-type organic thin film transistor was fabricated by the same method as in Example 1. The hole carrier mobility was 0.27 cm ² / V · s, and the current on / off ratio was 1.2 × 10 ⁷ . Therefore, since the mobility did not reach 0.5 cm ² / V · s, the material was insufficient in performance.

Comparative Example 4
Di n-pentyldithienobenzodithiophene (7.42 mg) obtained in Synthesis Example 6 and di-n-butyldithienobenzodithiophene (3.18 mg) obtained in Synthesis Example 8 were mixed to obtain a composition (general formula (1 ) / Thienobenzodithiophene derivative represented by the general formula (2) = 70 wt% / 30 wt%). Then, the total amount of the composition and 0.913 g of toluene (dehydrated grade made by Sigma-Aldrich) were mixed, dissolved by heating at 50 ° C., and then allowed to stand at room temperature (23 ° C.) for 12 hours. No crystal precipitation was observed, and the solution state of 1.15% by weight was maintained. Since the composition exhibited a solubility of 1.0% by weight or more, it was confirmed that the composition was a material suitable for film formation by inkjet.

  In addition, 5.36 mg of di-n-pentyldithienobenzodithiophene (70% by weight of a dithienobenzodithiophene derivative represented by the general formula (1)), 2.30 mg of di-n-butyldithienobenzodithiophene (general formula ( The dithienobenzodithiophene derivative (30% by weight) shown in 2) and 3.83 g of toluene (Pure grade manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and heated to 40 ° C. to prepare a solution (0.20% by weight).

Then, a bottom gate-top contact type p-type organic thin film transistor was fabricated by the same method as in Example 1. The hole carrier mobility was 0.37 cm ² / V · s, and the current on / off ratio was 1.3 × 10 ⁷ . Therefore, since the mobility did not reach 0.5 cm ² / V · s, the material was insufficient in performance.

  The novel dithienobenzodithiophene derivative composition of the present invention provides a high carrier mobility and is excellent in solubility in a solvent, so that an organic semiconductor thin film can be easily produced. Application as a semiconductor device material is expected.

; It is a figure which shows the structure by the cross-sectional shape of an 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 (1)

A method for producing an organic thin film transistor in which an organic semiconductor layer provided with a source electrode and a drain electrode and a gate electrode are laminated on a substrate via an insulating layer, wherein the organic semiconductor layer is an aromatic system having 7 to 14 carbon atoms An organic semiconductor layer formed by subjecting a solution of a dithienobenzodithiophene derivative composition having a solubility of 1% by weight or more to a hydrocarbon solvent at room temperature to a drop casting method, the dithienobenzodithiophene derivative composition dithienobenzodithiophenes derivatives 99 to 80 wt% and dithienobenzodithiophenes derivatives 1-20 wt% of the following general formula (2) represented by the following general formula (1) Tona distearate Chienobenzo A method for producing an organic thin film transistor, which is a dithiophene derivative composition.

(Here, the substituents R ¹ and R ² are the same or different and represent a substituent selected from the group consisting of an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group.)

(Here, the substituents R ³ and R ⁴ are the same or different and represent a substituent selected from the group consisting of an ethyl group, an n-propyl group, and an n-butyl group.)

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