JP2018043947A - Heteroacene derivative, organic semiconductor layer, and organic thin-film transistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel heteroacene derivative which is a coating type organic semiconductor material having high carrier mobility, high solubility, and high oxidation resistance, and to provide an organic semiconductor layer and an organic thin-film transistor using the heteroacene derivative.SOLUTION: The heteroacene derivative is represented by general formula (1) (where substituents R-Reach independently represent hydrogen, a halogen, a 2-20C alkyl group, a 1-20C acyl group, a 2-20C alkenyl group, or a 2-20C alkynyl group, provided that the case where all of the substituents R-Rare simultaneously hydrogen is excluded; and Tand Teach independently represent a sulfur atom, an oxygen atom, or a selenium atom).SELECTED DRAWING: None

Description

  The present invention relates to a novel heteroacene derivative that 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 has particularly excellent electrical characteristics, solubility, and oxidation resistance. In addition, the present invention relates to a novel heteroacene derivative applicable to various device manufacturing processes, an organic semiconductor layer using the same, and an organic thin film transistor.

  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-semiconductor material which comprises this organic-semiconductor layer, the appearance of the organic-semiconductor material which gives a high carrier mobility is desired.

  As a method for producing an organic semiconductor layer, generally known are a vacuum deposition method in which an organic material is vaporized under a high temperature vacuum, and a coating method in which an organic material is dissolved in an appropriate solvent and applied. It has been. Of these, the coating method can be carried out using printing technology that does not require high-temperature and high-vacuum conditions, so it can be expected to greatly reduce the manufacturing cost of device fabrication, and is an economically preferable process. is there.

  The organic semiconductor material used in such a coating method preferably has a solubility of 1.0% by weight or more at room temperature from the viewpoint of adapting to the printing process. Moreover, it is preferable to have oxidation resistance in order to operate stably in the atmosphere.

  Here, it is generally known that a low molecular semiconductor has a high crystallinity compared to a high molecular semiconductor and thus easily exhibits high carrier mobility. However, there are few known low molecular organic semiconductor materials that combine high carrier mobility, high solubility, and high oxidation resistance.

  Currently, pentacene is widely known as a low molecular weight material. Although pentacene is known to have high carrier mobility, it has a problem in oxidation resistance such as being easily oxidized by air in a solution state.

  As a low molecular weight material having oxidation resistance, a substance having a thiophene ring has been proposed. For example, 2,7-dihexyldithienobenzodithiophene (see, for example, Patent Document 1 and Patent Document 2), dialkyl substitution. Dinaphthothienothiophene (see, for example, Patent Document 3) has been proposed.

However, the 2,7-dihexyldithienobenzodithiophene proposed in Patent Document 1 and Patent Document 2 shows a mobility of 0.1 cm ² / V · s by the drop cast method, but has a solubility in a solvent at room temperature. Has a problem. Further, the dialkyl-substituted dinaphthothienothiophene proposed in Patent Document 3 shows high mobility by the vacuum deposition method, but the solubility in toluene at 60 ° C. is less than 0.01 wt%, and it is difficult to adapt to the printing process. is there.

  On the other hand, other substances having a thiophene ring have been developed, and anthra [1,2-b: 8,7-b ′] dithiophene is disclosed (for example, see Patent Document 4 and Non-Patent Documents 1 to 3). .) However, various anthrac [1,2-b: 8,7-b ′] dithiophene derivatives have been synthesized so far, but no compound for use in a coated organic transistor element has been reported. .

Special table 2011/526588 gazette JP 2012/209329 A Japanese Patent No. 5675916 Korean Patent No. 1094701

Journal of American Chemical Society, 1997, 119, 4578-4593 Journal of the Indian Chemical Society, 1999, 76, 569-573 Synthetic Communication, 2000, 30, 3569-3573

  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 solubility, and high oxidation resistance.

  As a result of intensive studies to solve the above problems, the present inventor can obtain an organic thin film transistor having high carrier mobility, high solubility, and high oxidation resistance by using a novel heteroacene derivative. As a result, the present invention has been completed.

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

（ここで、置換基Ｒ^１〜Ｒ^９は、それぞれ独立して、水素、ハロゲン、炭素数２〜２０のアルキル基、炭素数１〜２０のアシル基、炭素数２〜２０のアルケニル基、又は炭素数２〜２０のアルキニル基を示す。ただし、置換基Ｒ^１〜Ｒ^９が全て同時に水素である場合を除く。Ｔ^１及びＴ^２は、それぞれ独立して硫黄原子、酸素原子、又はセレン原子を示す。）
以下に本発明を詳細に説明する。

(Here, the substituents R ^{1 to} R ⁹ are each independently hydrogen, halogen, an alkyl group having 2 to 20 carbon atoms, an acyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or An alkynyl group having 2 to 20 carbon atoms, except that the substituents R ^{1 to} R ⁹ are all simultaneously hydrogen, and T ¹ and T ² are each independently a sulfur atom, an oxygen atom, or a selenium atom. Is shown.)
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 each of the substituents R ^{1 to} R ⁹ is independently hydrogen, halogen, an alkyl group having 2 to 20 carbon atoms, or a carbon number. An acyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms is shown. However, the case where the substituents R ^{1 to} R ⁹ are all simultaneously hydrogen is excluded. T ¹ and T ² each independently represent a sulfur atom, an oxygen atom, or a selenium atom.

Examples of the halogen in the substituents R ^{1 to} R ⁹ include chlorine, bromine, iodine, fluorine and the like, and bromine and iodine are preferable because of high reactivity.

Examples of the alkyl group having 2 to 20 carbon atoms in the substituents R ^{1 to} R ⁹ include an ethyl group, an n-propyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an n-hexyl group, and an n-heptyl group. N-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group And linear or branched alkyl groups such as n-octadecyl group, n-nonadecyl group, n-icosyl group, 2-ethylhexyl group, 3-ethylheptyl group, and 3-ethyldecyl group. Among them, an alkyl group having 3 to 10 carbon atoms is preferable because it is a heteroacene derivative exhibiting particularly high mobility and high solubility, and includes n-butyl group, n-pentyl group, n-hexyl group, and n-heptyl. And more preferably an n-octyl group.

Examples of the acyl group having 1 to 20 carbon atoms in the substituents R ^{1 to} R ⁹ include a formyl group, acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group, Decanoyl group, undecanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, pentadecanoyl group, hexadecanoyl group, heptadecanoyl group, octadecanoyl group, nonadecanoyl group, icosanoyl group, 2-ethylhexanoyl group, 3- Examples thereof include linear or branched acyl groups such as an ethylheptanoyl group and a 3-ethyldecanoyl group. Among them, an acyl group having 3 to 10 carbon atoms is preferable because it is a heteroacene derivative exhibiting particularly high mobility and high solubility, and is preferably a butyryl group, a valeryl group, a hexanoyl group, a heptanoyl group, or an octanoyl group. Further preferred.

Examples of the alkenyl group having 2 to 20 carbon atoms in the substituents R ^{1 to} R ⁹ include ethenyl group, n-propenyl group, n-butenyl group, n-pentenyl group, n-hexenyl group, n-heptenyl group, n- Octenyl, n-nonel, n-decenyl, n-undecenyl, n-dodecenyl, n-tridecenyl, n-tetradecenyl, n-pentadecenyl, n-hexadecenyl, n-heptadecenyl, n- Examples thereof include alkenyl groups such as octadecenyl group, n-nonadecenyl group, and n-icosenyl group.

Examples of the alkynyl group having 2 to 20 carbon atoms in the substituents R ^{1 to} R ⁹ include ethynyl group, n-propynyl group, n-butynyl group, n-pentynyl group, n-hexynyl group, n-heptynyl group, n -Octynyl group, n-noninyl group, n-decynyl group, n-undecynyl group, n-dodecynyl group, n-tridecynyl group, n-tetradecynyl group, n-pentadecynyl group, n-hexadecynyl group, n-heptadecynyl group, n -Alkynyl groups, such as an octadecynyl group, n-nonadecynyl group, n-icosinyl group, are mentioned.

In the present invention, when all of the substituents R ^{1 to} R ⁹ are simultaneously hydrogen, the solubility is reduced due to a strong π-π interaction between rigid heteroacene condensed polycyclic skeletons. Further, the heteroacene derivative according to the present invention has a lower solubility due to its structural characteristics. That is, in the heteroacene derivative, due to the presence of T ¹ and T ² having high electronegativity, the line symmetry axis direction of the heteroacene derivative according to the present invention (the direction of the line connecting the center point of T ¹ and T ² and R ⁹⁾ ), Polarization occurs. Due to the presence of the polarization, the heteroacene derivative according to the present invention is polar and has low solubility in a general-purpose organic solvent (nonpolar solvent). Therefore, in the present invention, when all of the substituents R ^{1 to} R ⁹ are hydrogen at the same time, the highly soluble heteroacene derivative, which is a feature of the present invention, cannot be obtained. Therefore, in the present invention, the substituents R ^{1 to} R ⁹ are The case of all hydrogen at the same time is excluded.

In the present invention, the substituents R ^{5 to} R ⁹ are preferably hydrogen because of high mobility. Examples of the substituents ^R 1 to R ^4, for high mobility, halogen, alkyl group having 2 to 20 carbon atoms, an acyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, 2 carbon atoms It is preferably selected from the group consisting of 20 alkynyl groups, and in order to achieve both high mobility and high solubility, R ^{1 to} R ⁴ are more preferably alkyl groups having 2 to 20 carbon atoms, and R ¹ and It is particularly preferable that R ² is an alkyl group having 2 to 20 carbon atoms, and R ³ and R ⁴ are hydrogen. In the present invention, since the heteroacene derivative according to the present invention is a heteroacene derivative having the substituent, in addition to strong π-π interaction between rigid heteroacene fused polycyclic skeletons, aggregation between alkyl side chains The effect enables favorable molecular arrangement, and better carrier mobility can be expressed. At the same time, higher solubility can be expressed by the bent heteroacene fused polycyclic skeleton and the degree of freedom of the alkyl side chain. Thereby, an organic semiconductor material having both higher carrier mobility and higher solubility becomes possible.

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, an oxygen atom, or a selenium atom. In the present invention, a sulfur atom, an oxygen atom, or a selenium atom having a higher electronegativity than a carbon atom is introduced into the condensed ring skeleton, so that the HOMO level is lowered and the oxidation resistance is improved. It is what.

In the present invention, T ¹ and T ² are preferably sulfur atoms because of their particularly high mobility.

  Specific examples of the heteroacene derivative used in the present invention include the following.

なお、一般式（１）で示されるヘテロアセン誘導体としては、より高い移動度、より高い溶解性、及びより高い耐酸化性のため、Ｒ^１及びＲ^２が炭素数４〜８の直鎖アルキル鎖、Ｒ^３〜Ｒ^９が水素、並びにＴ^１及びＴ^２が硫黄であるヘテロアセン誘導体（化合物１〜化合物５）が好ましい。

As the heteroacene derivative represented by the general formula (1), R ¹ and R ² are linear alkyl chains having 4 to 8 carbon atoms for higher mobility, higher solubility, and higher oxidation resistance. , R ^{3 to} R ⁹ are hydrogen, and T ¹ and T ² are sulfur heteroacene derivatives (compounds 1 to 5).

  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, when producing a heteroacene derivative in which the substituents R ¹ and R ² are alkyl groups having 2 to 20 carbon atoms and the substituents R ^{3 to} R ⁹ are hydrogen, The Journal of Organic Chemistry, 1985, Volume 50, A heteroacene derivative can be produced by the method described in pages 3104 to 3110 (a production method through the steps of the following reaction scheme (A)) and a production method through the following steps (B) to (D).
Step (A): A step of producing 1,5-dibromo-2,4-diiodobenzene from 1,3-dibromobenzene and iodine in concentrated sulfuric acid.
(B) step; 2-alkylthiophene-5-zinc derivative derived from 2-alkyl-5-bromothiophene in the presence of a palladium catalyst, and 1,5-dibromo-2, obtained by step (A) A step of producing 1,5-dibromo-2,4-di (5-alkylthiophen-2-yl) benzene from 4-diiodobenzene.
(C) Step; Sonogashira Cup of 1,5-dibromo-2,4-di (5-alkylthiophen-2-yl) benzene and trimethylsilylacetylene obtained by (B) step in the presence of palladium / copper catalyst A step of producing 1,5-diethynyl-2,4-di (5-alkylthiophen-2-yl) benzene by a ring and detrimethylsilyl reaction.
Step (D): In the presence of a ruthenium catalyst, heteroacene derivative (1) is obtained by intramolecular cyclization of 1,5-diethynyl-2,4-di (5-alkylthiophen-2-yl) benzene obtained in Step (C). The step of producing 1a).
And since the number of reaction steps is small, a more specific production method which is preferable is shown in the following reaction scheme.

（ここで、置換基Ｒ^１０は、炭素数２〜２０のアルキル基を示す。）
ここで、（Ａ）〜（Ｄ）工程の詳細を以下に示す。

(Here, the substituent R ¹⁰ represents an alkyl group having 2 to 20 carbon atoms.)
Here, the details of the steps (A) to (D) are shown below.

  Here, step (A) in the reaction scheme is a step of producing 1,5-dibromo-2,4-diiodobenzene from 1,3-dibromobenzene and iodine in concentrated sulfuric acid. As reaction temperature, it can implement within the range of 50 to 150 degreeC.

  Step (B) in the reaction scheme includes a 2-alkylthiophene-5-zinc derivative derived from 2-alkyl-5-bromothiophene in the presence of a palladium catalyst and 1,5 obtained by step (A). A process for producing 1,5-dibromo-2,4-di (5-alkylthiophen-2-yl) benzene from dibromo-2,4-diiodobenzene.

  Examples of the palladium catalyst include tetrakis (triphenylphosphine) palladium, dichlorobis (triphenylphosphine) palladium and the like, and the reaction temperature can be carried out within a range of 20 ° C to 80 ° C.

  The 2-alkylthiophene-5-zinc derivative is obtained by exchanging bromine at the 5-position of 2-alkyl-5-bromothiophene with lithium using an organic metal reagent such as n-butyllithium or tert-butyllithium (mono). Preparation of lithium salt) and metal exchange with zinc chloride. Alternatively, a magnesium metal can be used in place of the organometallic reagent to prepare a Grignard reagent of 2-alkyl-5-bromothiophene, and metal exchange with zinc chloride is possible.

  The conditions for preparing the monolithium salt of 2-alkyl-5-bromothiophene are, for example, carried out in a temperature range of −80 ° C. to 20 ° C. in a solvent such as tetrahydrofuran (hereinafter referred to as THF) or diethyl ether. can do. When zinc chloride is reacted with the monolithium salt solution, the zinc chloride may be used as it is, or it may be a THF or diethyl ether solution. The temperature of the reaction between the monolithium salt and zinc chloride can be carried out within a range of -80 ° C to 30 ° C.

  Step (C) in the reaction scheme is carried out in the presence of a palladium / copper catalyst in the presence of 1,5-dibromo-2,4-di (5-alkylthiophen-2-yl) benzene and trimethylsilyl obtained in step (B). In this process, 1,5-diethynyl-2,4-di (5-alkylthiophen-2-yl) benzene is produced by Sonogashira coupling of acetylene and detrimethylsilyl reaction.

  In this case, examples of the palladium catalyst include tetrakis (triphenylphosphine) palladium, dichlorobis (triphenylphosphine) palladium, and the copper catalyst includes copper iodide (I), copper bromide (I), copper chloride. (I) etc. can be mentioned. The Sonogashira coupling can be carried out in a temperature range of 20 ° C. to 80 ° C. in a solvent such as triethylamine, pyridine, toluene, and THF.

  The detrimethylsilyl reaction can be carried out using a desilylating agent such as tetrabutylammonium fluoride and dilute hydrochloric acid in a solvent such as THF, toluene, dichloromethane and the like in a temperature range of 0 ° C to 50 ° C.

  In step (D) in the reaction scheme, an intramolecular ring of 1,5-diethynyl-2,4-di (5-alkylthiophen-2-yl) benzene obtained in step (C) in the presence of a ruthenium catalyst. This is a process for producing a heteroacene derivative (1a) by crystallization.

  Examples of the ruthenium catalyst include a triphenylphosphine (cymene) ruthenium chloride complex, and the intramolecular cyclization can be carried out in a temperature range of 20 to 100 ° C. in a solvent such as 1,2-dichloroethane. it can. In addition, it is preferable to coexist ammonium hexafluorophosphate for promoting the reaction.

  Furthermore, the produced heteroacene derivative can be purified by subjecting it to column chromatography or the like, and as a separating agent at that time, for example, silica gel, activated alumina, and as a solvent, hexane, heptane, toluene, dichloromethane, chloroform Etc.

  The produced heteroacene derivative can be decolorized and purified in a solution by subjecting it to activated carbon, zeolite, activated clay, etc. Examples of the solvent include hexane, heptane, toluene, dichloromethane, chloroform and the like.

  Further, the produced heteroacene derivative may be further purified by recrystallization, and the number of recrystallizations is preferably 2 to 5 times in order to improve the purity and yield. 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 further preferred.) By cooling the solution, crystals of the heteroacene derivative are precipitated and isolated, but the final cooling temperature at the time of isolation is to improve purity and recovery. Therefore, it 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 may be used as long as it can dissolve the heteroacene derivative represented by the general formula (1), and when the organic semiconductor layer is formed, the drying rate of the solvent is preferably set. 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 Group hydrocarbons: anisole, 2-methylanisole, 3-methylanisole, 2,3-dimethylanisole, 3,4-dimethylanisole, 2,6-dimethylanisole, ethylphenylether, butylphenylether, 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; cyclohexane , Octane, decane, de Saturated hydrocarbons such as can 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 -Glycols such as 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 monobutyl ether acetate; phenyl acetate , Cyclohexanol acetate, 3-methoxybutyl acetate, etc. Among them, among them, since it has an appropriate drying rate, preferably toluene, o-xylene, mesitylene, 1,2,4-trimethylbenzene, tetralin, indane, anisole, 2-methylanisole, 3-methylanisole, 2,3-dimethylanisole, 3,4-dimethylanisole, 2,6-dimethylanisole, ethylphenyl ether, butylphenyl ether, 1,2-methylenedioxybenzene, 1,2-ethylenedioxy Benzene, 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 aniso And 3,4-dimethylanisole and 2,6-dimethylanisole.

  In addition, the solvent used by this invention can use one type of solvent independently, It is also possible to mix and use two or more types of solvents from which properties differ, such as a boiling point, a polarity, and a solubility parameter.

  As the temperature at which the heteroacene derivative represented by the general formula (1) is mixed and dissolved in a solvent, it is preferably performed in a temperature range of 0 to 80 ° C. for the purpose of promoting dissolution, and a temperature range of 10 to 60 ° C. 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 organic semiconductor layer forming solution of the present invention is in the range of 0.1 to 10.0% by weight, the handling becomes easy. It becomes more excellent in the efficiency at the time of forming. Moreover, when the viscosity of the solution for forming an organic semiconductor layer is in the range of 0.3 to 10 mPa · s, more suitable coating properties are 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, for example, a polymer such as polystyrene, poly (α-methylstyrene), polyvinyl naphthalene, ethylene-norbornene copolymer, polyphenylene ether, polymethyl methacrylate, polyarylamine, polyfluorene as a binder. The concentration of these polymer binders is preferably 0.1 to 10.0% by weight for an appropriate solution viscosity. Moreover, since the solution when making a polymer exist as a binder has the outstanding applicability | paintability, it is preferable that it is the viscosity of the range of 0.5-50 mPa * s.

  The coating method for forming the organic semiconductor layer using the organic semiconductor layer forming solution of the present invention is not particularly limited as long as it is a method capable of forming the organic semiconductor layer. For example, spin coating, drop cast, 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. Therefore, spin coating and ink jet are preferable.

  After applying the organic semiconductor layer forming solution of the present invention, the organic semiconductor layer can be formed by drying and removing the solvent.

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

  Although there is no restriction | limiting in particular in the temperature which dry-removes an organic solvent from the apply | coated organic-semiconductor layer, Since an organic solvent can be efficiently removed by dry-dry from the apply | coated organic-semiconductor layer, an organic-semiconductor layer can be formed. , Preferably in the temperature range of 10 to 150 ° C.

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

  The film thickness of the organic semiconductor layer formed by the organic semiconductor layer forming solution of the present invention is not limited, and good carrier movement is obtained. Therefore, it is preferably in the range of 1 nm to 1 μm, and in the range of 10 nm to 300 nm. More preferably.

  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 organic semiconductor layer forming solution 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 that exhibits excellent semiconductor and electrical characteristics 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 is formed from the organic semiconductor layer forming solution of the present invention. The organic semiconductor layer to be applied 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, polyvinylphenol, Plastic substrates such as polyvinyl alcohol, poly (diisopropyl fumarate), poly (diethyl fumarate), poly (diisopropyl maleate), polyethersulfone, polyphenylene sulfide, cellulose triacetate; glass, quartz, aluminum oxide, silicon, highly doped silicon Inorganic material substrates such as silicon oxide, tantalum dioxide, tantalum pentoxide, and indium tin oxide; 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 such as doped conductive polymers (eg, PEDOT-PSS).

  The inorganic material can be used as a metal nanoparticle ink. In this case, the solvent is a polar solvent such as water, methanol, ethanol, isopropanol, 1-butanol, and 2-butanol for moderate dispersibility; carbon number 6 to 6 such as hexane, heptane, octane, decane, dodecane, and tetradecane. 14 aliphatic hydrocarbon solvents; toluene, xylene, mesitylene, ethylbenzene, pentylbenzene, hexylbenzene, octylbenzene, cyclohexylbenzene, tetralin, indane, anisole, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1, It is preferably an aromatic hydrocarbon solvent having 7 to 14 carbon atoms such as 2-dimethylanisole, 2,3-dimethylanisole, and 3,4-dimethylanisole. After applying the nanoparticle ink, it is preferable to perform an annealing treatment in a temperature range of 80 ° C. to 200 ° C. in order to improve 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 acid and bismuth titanate; polymethyl methacrylate, polymethyl acrylate, polyimide, polycarbonate, polyvinyl phenol, polyvinyl alcohol, poly (diisopropyl fumarate), poly (diethyl fumarate), polyethylene terephthalate, polyethylene naphthalate, Polyethyl cinnamate, polymethyl cinnamate, ethyl polycrotonate, polyethersulfone, polypropylene-co-1-butene, polyisobutylene, polypropylene, polycyclopentane Polycyclohexane, polycyclohexane-ethylene copolymer, polyfluorinated cyclopentane, polyfluorinated cyclohexane, polyfluorinated cyclohexane-ethylene copolymer, BCB resin (manufactured by Dow Chemical (trade name: Cycloten)), Cytop ( (Trademarks), Teflon (trademark), Parylene (trademarks) such as Parylene C, and the like, and because the manufacturing method is simple, a polymer insulation material (polymer gate insulation layer) to which a coating method can be applied It is preferable that

  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 dimethylformamide and N-methylpyrrolidone; Dipropylene glycol dimethyl ether and 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, Glycol solvents such as 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 monobutyl ether acetate; perfluorohexane, perfluorooctane, 2 -(Pentafluoroethyl) hexane, 3- (pentafluoroethyl) heptane, etc. Examples include fluorinated solvents.

  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 a viewpoint of insulation resistance, 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, phenyltri Silanes such as chlorosilane and phenyltrimethoxysilane; phosphonic acids such as octadecylphosphonic acid, decylphosphonic acid and octylphosphonic acid; 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 carrier mobility, current on / off ratio, and threshold voltage. Results are 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, which may be the same as or different from the material of the gate electrode. May be laminated. In order to increase the carrier injection efficiency, surface treatment can be performed on these electrode materials. Examples of the manifestation treatment agent used for the 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 operation. In addition, the current on / off ratio is preferably 1.0 × 10 ⁶ or more for 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 high carrier mobility and high solubility and high oxidation resistance. Therefore, it is possible to provide an organic thin film transistor that exhibits excellent semiconductor characteristics upon coating. The effect is extremely high.

; It is a figure which shows the structure by the cross-sectional shape of an organic thin-film transistor.

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

  The product was identified by mass spectrum (MS), gas chromatography-mass spectrum (GCMS), and liquid chromatography-mass spectrum (LCMS) analysis.

<Mass spectrum (MS) analysis>
Device: JEOL (trade name) JEOL JMS-700
MS ionization; electron impact (EI) method (70 electron volts)
Sample introduction; direct introduction <Gas chromatography-mass spectrum analysis>
Equipment: Perkin Elmer, (trade name) Auto System XL (MS part: Turbomass Gold)
Column; J & W Scientific (trade name) DB-1, 30 m.
MS ionization; electron impact (EI) method (70 electron volts)
<Liquid chromatography-mass spectrum (LCMS) analysis>
Equipment: Bruker Daltonics, (trade name) microTOF focus
MS ionization; atmospheric pressure chemical ionization (APCI) method LC conditions; conditions described in the following liquid chromatography analysis items The confirmation of the progress of the reaction, etc. was performed using gas chromatography (GC) and liquid chromatography (LC) analysis.

<Gas chromatography analysis>
Equipment: Made by Shimadzu Corporation (trade name) GC14B
Column; made by J & W Scientific, (trade name) DB-1, 30 m
Liquid chromatographic analysis was used to measure the purity of the heteroacene derivative.

<Liquid chromatography analysis>
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: 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 1,5-dibromo-2,4-diiodobenzene) (step (A))
Under a nitrogen atmosphere, in a 200 ml Schlenk reaction vessel, 1.3-dibromobenzene (Tokyo Chemical Industry) 2.18 g (9.26 mmol), iodine (Tokyo Chemical Industry) 4.94 g (19.4 mmol), and concentrated at room temperature. 50 mL of sulfuric acid was added and stirred at 130 ° C. for 6 hours. The vessel was cooled to room temperature, and the resulting mixture was poured into ice water to stop the reaction. The precipitated crystals were filtered and washed sequentially with an aqueous sodium bisulfite solution, sodium bicarbonate, and water, respectively. The obtained crystals were recrystallized and purified once from toluene to obtain 2.71 g of white crystals of 1,5-dibromo-2,4-diiodobenzene (yield 60%).
MS m / z: 488 (M ^<+> ).

Synthesis Example 2 (Synthesis of 1,5-dibromo-2,4-di (5-n-hexylthiophen-2-yl) benzene) (Step (B))
Under a nitrogen atmosphere, 3.94 g (15.9 mmol) of 2-bromo-5-n-hexylthiophene (Tokyo Chemical Industry) and 100 ml of diethyl ether (dehydrated grade) were added to a 500 ml Schlenk reaction vessel. This solution was cooled to −78 ° C., and 10.9 ml (17.5 mmol) of a hexane solution of n-butyllithium (Kanto Chemical, 1.6M) was added dropwise. The mixture was aged at -78 ° C for 1 hour. On the other hand, 3.79 g (20.4 mmol) of zinc chloride (Wako Pure Chemical Industries) and 60 ml of THF (dehydrated grade) were added to another 200 ml Schlenk reaction vessel in a nitrogen atmosphere and cooled to 0 ° C. The obtained white fine slurry solution was dropped into the previously prepared monolithium salt of 2-bromo-5-n-hexylthiophene using a Teflon cannula, and further using 5 ml of THF (dehydrated grade). A 200 ml Schlenk reaction vessel and a Teflon cannula were added while washing. The resulting mixture was stirred while gradually warming to room temperature. To the produced slurry of 2-n-hexylthiophene-5-zinc derivative, 2.59 g (5.32 mmol) of 1,5-dibromo-2,4-diiodobenzene synthesized in Synthesis Example 1 and tetrakis ( 307 mg (0.266 mmol, 5.00 mol% based on 1,5-dibromo-2,4-diiodobenzene) of triphenylphosphine) palladium (Tokyo Chemical Industry) was added. After carrying out the reaction at 50 ° C. for 15 hours, the vessel was cooled with water and the reaction was stopped by adding 25 ml of 1M hydrochloric acid. Extraction was performed with toluene, and the organic phase was washed with brine and dried over anhydrous sodium sulfate. The residue was purified by silica gel column chromatography (developing solvent: toluene). Concentrated under reduced pressure, and the resulting residue was washed with hexane. The obtained residue was purified by recrystallization from hexane / toluene = 3/1 to obtain 1.36 g of a light yellow solid of 1,5-dibromo-2,4-di (5-n-hexylthiophen-2-yl) benzene. Obtained (yield 45%).
MS m / z: 568 (M ^<+> ).

Synthesis Example 3 (Synthesis of 1,5-diethynyl-2,4-di (5-n-hexylthiophen-2-yl) benzene) (Step (C))
In a 100 ml Schlenk reaction vessel in a nitrogen atmosphere, 1.33 g (2.34 mmol) of 1,5-dibromo-2,4-di (5-n-hexylthiophen-2-yl) benzene synthesized in Synthesis Example 2 and dichlorobis (Triphenylphosphine) palladium (Wako Pure Chemical Industries) 32.8 mg (0.0468 mmol), copper (I) iodide (Wako Pure Chemical Industries) 17.8 mg (0.0936 mmol), THF 8 ml, triethylamine 4 ml, trimethylsilylacetylene ( 506 mg (5.15 mmol) of Wako Pure Chemical Industries) was added. The mixture was reacted at room temperature (25 ° C.) for 20 hours. Toluene and 1M hydrochloric acid aqueous solution were added to the obtained reaction mixture, and after phase separation, the organic phase was washed with water and dried over anhydrous sodium sulfate. The organic phase was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (solvent; hexane: toluene = 20: 1 to 5: 1). To the purified isolate, 10 ml of THF and 6.0 ml (6.0 mmol) of tetrabutylammonium fluoride (Sigma-Aldrich, 1.0 mol / l THF solution) were added, followed by detrimethylylsilyl treatment by stirring at room temperature for 1 hour. . Toluene and 1M aqueous hydrochloric acid were added, and after phase separation, the organic phase was washed with water and dried over anhydrous sodium sulfate. The organic phase was concentrated under reduced pressure to obtain 612 mg of yellow solid of 1,5-diethynyl-2,4-di (5-n-hexylthiophen-2-yl) benzene (57% yield).
MS m / z: 458 (M ^<+> , 100%).

Example 1 (Synthesis of heteroacene derivative (2,10-di-n-hexylanthra [1,2-b: 8,7-b ′] dithiophene) (compound 3)) (step (D))
Under a nitrogen atmosphere, in a 100 ml Schlenk reaction vessel, 70.5 mg (0.124 mmol) of triphenylphosphine (cymene) ruthenium chloride complex (Strem), 40.4 mg (0.248 mmol) of ammonium hexafluorophosphate (Wako Pure Chemical Industries), And 15 ml of 1,2-dichloroethane were added and heated to 60 ° C. A solution comprising 568 mg (1.24 mmol) of 1,5-diethynyl-2,4-di (5-n-hexylthiophen-2-yl) benzene synthesized in Synthesis Example 3 and 15 ml of 1,2-dichloroethane was added dropwise. The mixture was added dropwise using a funnel and heated at 60 ° C. for 8 hours. After removing the solvent under reduced pressure, toluene and water were added, and the precipitated solid was filtered. The solid was washed with water and methanol, and then purified by silica gel column chromatography (developing solvent: hexane / toluene = 10/1), and the obtained compound was recrystallized and purified from hexane / toluene = 3/1 three times. 142 mg of pale yellow crystals of the heteroacene derivative (2,10-di-n-hexylanthra [1,2-b: 8,7-b ′] dithiophene) (compound 3) were obtained (yield 25%).

The purity of the obtained heteroacene derivative (2,10-di-n-hexylanthra [1,2-b: 8,7-b ′] dithiophene) (compound 3) was 99.3% by liquid chromatography.
LCMS m / z: 459 (M ⁺ +1, 100%)
Synthesis Example 4 (Synthesis of 1,5-dibromo-2,4-di (5-n-octylthiophen-2-yl) benzene) (Step (B))
Instead of 2-bromo-5-n-hexylthiophene used in Synthesis Example 2, 2-bromo-5-n-octylthiophene (Tokyo Chemical Industry) was used in the same manner as in Synthesis Example 2, A pale yellow solid of 1,5-dibromo-2,4-di (5-n-octylthiophen-2-yl) benzene was obtained in a yield of 50%.

Synthesis Example 5 (Synthesis of 1,5-diethynyl-2,4-di (5-n-octylthiophen-2-yl) benzene) (Step (C))
Instead of 1,5-dibromo-2,4-di (5-n-hexylthiophen-2-yl) benzene used in Synthesis Example 3, 1,5-dibromo-2,4- synthesized in Synthesis Example 4 was used. Except that di (5-n-octylthiophen-2-yl) benzene was used, 1,5-diethynyl-2,4-di (5-n-octylthiophen-2-yl) was obtained in the same manner as in Synthesis Example 3. I) A yellow solid of benzene was obtained in a yield of 62%.

Example 2 (Synthesis of heteroacene derivative (2,10-di-n-octylanthra [1,2-b: 8,7-b ′] dithiophene) (compound 5)) (step (D))
1,5-diethynyl-2,4- synthesized in Synthesis Example 5 instead of 1,5-diethynyl-2,4-di (5-n-hexylthiophen-2-yl) benzene used in Example 1 Except for using di (5-n-octylthiophen-2-yl) benzene, a heteroacene derivative (2,10-di-n-octylanthra [1,2-b: 8, 7-b ′] dithiophene) (compound 5) was obtained in a yield of 30%.

Example 3
(Preparation of organic semiconductor layer forming solution)
In a 10 ml sample tube under air, 13.5 mg of the heteroacene derivative (2,10-di-n-hexylanthra [1,2-b: 8,7-b ′] dithiophene) obtained in Example 1 (Compound 3) And 1.34 g of toluene (Wako Pure Chemical Industries, Pure Grade) were added, dissolved by heating at 50 ° C., and then left at room temperature (25 ° C.) for 12 hours. Since no crystal precipitation was observed and the solution state of 1.0% by weight was maintained, it was confirmed that the material was suitable for the printing process.

  In addition, for confirmation of oxidation resistance, the purity was confirmed immediately after the preparation of the solution and after contact with the outside air. The purity of the compound immediately after preparation of the solution was 99.3% by liquid chromatography. The solution was brought into contact with the outside air, stirred at 70 ° C., and then analyzed by liquid chromatography. As a result, no decrease in purity was observed, confirming that it had oxidation resistance.

(Production of organic semiconductor layer)
In a 10 ml sample tube under air, 1.5 mg of the heteroacene derivative (2,10-di-n-hexylanthra [1,2-b: 8,7-b ′] dithiophene) obtained in Example 1 (compound 3) And toluene (Wako Pure Chemical Industries, pure grade) 0.75g was added, and it heated at 40 degreeC, and prepared the solution (0.20 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. The solution that passed through a 2 μm filter was drop cast. A thin film of a heteroacene derivative (2,10-di-n-hexylanthra [1,2-b: 8,7-b ′] dithiophene) (compound 3) having a film thickness of 49 nm is naturally dried at room temperature (25 ° C.). Produced.

(Production of organic thin film transistor)
A shadow mask having a channel length of 50 μm and a channel width of 500 μm was placed on the organic thin film, and gold was vacuum-deposited to form an electrode, thereby producing a bottom gate-top contact type p-type organic thin film transistor.

Using the semiconductor parameter analyzer (Keutley 4200SCS), the electrical properties of the fabricated organic thin film transistor are scanned with a drain voltage (Vd = −70 V) and a gate voltage (Vg) from +5 to −70 V in increments of 1 V to evaluate transfer characteristics. Went. The hole carrier mobility was 0.56 cm ² / V · s, and the current on / off ratio was 1.5 × 10 ⁷ .

Example 4
(Preparation of organic semiconductor layer forming solution)
In a 10 ml sample tube under air, 12.9 mg of the heteroacene derivative (2,10-di-n-octylanthra [1,2-b: 8,7-b ′] dithiophene) obtained in Example 2 (Compound 5) And 1.28 g of toluene (Wako Pure Chemical Industries, Pure Grade) were added, dissolved by heating at 50 ° C., and then left at room temperature (25 ° C.) for 12 hours. Since no crystal precipitation was observed and the solution state of 1.0% by weight was maintained, it was confirmed that the material was suitable for the printing process.

  In addition, for confirmation of oxidation resistance, the purity was confirmed immediately after the preparation of the solution and after contact with the outside air. The purity of the compound immediately after preparation of the solution was 99.2% by liquid chromatography. The solution was brought into contact with the outside air, stirred at 70 ° C., and then analyzed by liquid chromatography. As a result, no decrease in purity was observed, confirming that it had oxidation resistance.

(Production of organic semiconductor layer)
In a 10 ml sample tube under air, 1.5 mg of the heteroacene derivative (2,10-di-n-octylanthra [1,2-b: 8,7-b ′] dithiophene) obtained in Example 2 (Compound 5) And toluene (Wako Pure Chemical Industries, pure grade) 0.75g was added, and it heated at 40 degreeC, and prepared the 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 filled and passed through a 0.2 μm filter was drop cast. A thin film of 55 nm-thick heteroacene derivative (2,10-di-n-octylanthra [1,2-b: 8,7-b ′] dithiophene) (compound 5) was dried at room temperature (25 ° C.). Produced.

(Production of organic thin film transistor)
A bottom gate-top contact type p-type organic thin film transistor was produced in the same manner as in Example 3.

The hole carrier mobility was 0.53 cm ² / V · s, and the current on / off ratio was 1.1 × 10 ⁷ .

Comparative Example 1
(Synthesis of organic semiconductors)
By the production method described in Non-Patent Document 2, unsubstituted heteroacene (anthra [1,2-b: 8,7-b ′] dithiophene) was obtained.

(Preparation of organic semiconductor layer forming solution)
In air, 13.5 mg of the above-mentioned unsubstituted heteroacene and 1.34 g of toluene (Wako Pure Chemical Industries, Pure Grade) were added to a 10 ml sample tube, heated and dissolved at 50 ° C., and then left at room temperature (25 ° C.) for 12 hours. (The concentration of unsubstituted heteroacene was 1.0% by weight). Crystallization was observed, a problem with solubility was confirmed, and it was confirmed that the material was not suitable for the printing process.

Comparative Example 2
(Synthesis of organic semiconductors)
By the production method described in Non-Patent Document 1, a heteroacene derivative represented by the following general formula (2) (4,8-bis (4-dodecyloxyphenyl) -2,10-dimethylanthra [1,2-b : 8,7-b ′] dithiophene).

（有機半導体層形成用溶液の調製）
空気下、１０ｍｌサンプル管に、上記ヘテロアセン誘導体１３．５ｍｇ及びトルエン（和光純薬工業、ピュアーグレード）１．３４ｇを添加し、５０℃に加熱溶解後、室温下（２５℃）に２４時間放置した。結晶の析出は見られず１．０重量％の溶液状態を保持していたことから、印刷プロセスに適した材料であることを確認した。

(Preparation of organic semiconductor layer forming solution)
Under air, 13.5 mg of the above heteroacene derivative and 1.34 g of toluene (Wako Pure Chemical Industries, Pure Grade) were added to a 10 ml sample tube, heated and dissolved at 50 ° C., and then allowed to stand at room temperature (25 ° C.) for 24 hours. . Since no crystal precipitation was observed and the solution state of 1.0% by weight was maintained, it was confirmed that the material was suitable for the printing process.

(Production of organic semiconductor layer)
Under air, 1.5 mg of the heteroacene derivative 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 wt%).

  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. The solution that passed through a 2 μm filter was drop cast. The film was naturally dried at room temperature (25 ° C.) to produce a 51 nm thick heteroacene derivative thin film.

(Production of organic thin film transistor)
A bottom gate-top contact type p-type organic thin film transistor was fabricated by the same method as in Example 3, and the transfer characteristics were evaluated. The carrier mobility of holes was 8.0 × 10 ⁻⁵ cm ² / A very low value of V · s was exhibited.

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

(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 (6)

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

(Here, the substituents R ^{1 to} R ⁹ are each independently hydrogen, halogen, an alkyl group having 2 to 20 carbon atoms, an acyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or An alkynyl group having 2 to 20 carbon atoms, except that the substituents R ^{1 to} R ⁹ are all simultaneously hydrogen, and T ¹ and T ² are each independently a sulfur atom, an oxygen atom, or a selenium atom. Is shown.) The heteroacene derivative according to claim 1, wherein the substituents R ^{1 to} R ⁹ are hydrogen or an alkyl group having 2 to 20 carbon atoms. The heteroacene derivative according to claim 1 or 2, wherein T ¹ and T ² are sulfur atoms. An organic semiconductor layer forming solution obtained by dissolving the heteroacene derivative according to any one of claims 1 to 3 in a solvent. An organic semiconductor layer obtained by using the organic semiconductor layer forming solution according to claim 4. An organic thin film transistor obtained by using the organic semiconductor layer according to claim 5.

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