JP2010083785A - Compound having molecular structure high in planarity and organic transistor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compound which can especially form a stable thin film on a bottom contact type organic transistor by a solution-coating method, and can form an organic semiconductor film having high mobility and a low threshold voltage and enabling stable operations in the atmosphere, and to provide an organic transistor using the compound. <P>SOLUTION: There is provided the compound represented by formula (I). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel compound having a highly planar molecular structure. Furthermore, this invention relates to the thin film, organic-semiconductor film, and organic transistor using the said compound.

  Conventionally, silicon has been used as an inorganic semiconductor material for transistors. When forming a thin film made of silicon on a substrate, a high temperature process and a high vacuum process are essential. However, since a high temperature process is required, plastic cannot be used as the substrate. Therefore, flexibility cannot be given to a product incorporating a transistor, and weight reduction cannot be achieved. In addition, since a high vacuum process is required, it is difficult to increase the area and cost of a product incorporating a transistor.

  Therefore, in recent years, research on organic transistors using organic semiconductor materials, particularly organic field effect transistors (hereinafter also referred to as “organic FETs”. Organic thin film transistors (hereinafter also referred to as “organic TFTs”) are also included in this organic FET classification. Research is actively conducted.

  An organic semiconductor material can be formed over a plastic substrate or the like because a manufacturing process temperature can be significantly reduced as compared with an inorganic semiconductor material such as silicon. Furthermore, when the organic semiconductor material has high solubility in a solvent and good film formability, a high vacuum process is not required, so a thin film is formed by a coating method, for example, a coating method using an inkjet apparatus. can do. Therefore, it is possible to increase the area and cost of a product incorporating a semiconductor device.

  As described above, organic semiconductor materials are advantageous in terms of large area, flexibility, weight reduction, cost reduction, and the like compared to inorganic semiconductor materials. Applications are actively being made. For example, it is applied to displays such as information tags, large area sensors such as electronic artificial skin sheets and sheet-type scanners, liquid crystal displays, electrophoretic displays (electronic paper), and organic EL panels.

The main performance required for an organic transistor using an organic semiconductor material is as follows. Note that the performance of a transistor is sometimes referred to as FET performance.
(1) The on / off ratio (on current / off current) is large and the off current is small.
(2) The threshold voltage is low.
(3) The cut-off frequency is high.
(4) Operates stably in the atmosphere and has little deterioration over time.
(5) The variation in the characteristics of (1) to (4) is small.
The characteristics required for the organic semiconductor material to satisfy these performances are as follows.
(I) Field effect mobility (μ) is high.
(Ii) The thin film formation process is easy and the film formability is excellent.
(Iii) Resistant to oxygen and moisture and stable in the atmosphere.
In particular, it is a major premise that the field effect mobility of (i) (hereinafter abbreviated as “mobility”) is high. From this viewpoint, in recent years, organic semiconductor materials having field effect mobility comparable to amorphous silicon have been reported one after another. The thin film formation process in (ii) includes a vacuum deposition method and a coating method. In the case of the vacuum vapor deposition method, it is preferable that vapor deposition can be performed at room temperature rather than high temperature from the viewpoint of easy thin film formation process. Further, when a coating method can be used, it is more preferable than the vacuum deposition method. The excellent film formability means that in the thin film formation process, the adhesion between the source / drain electrodes and the gate insulating film is good, and a uniform and continuous thin film can be formed.

  Organic semiconductor materials are roughly classified into low molecular weight systems (including oligomers) and high molecular weight systems. An example of the low molecular organic semiconductor material is pentacene. It has been reported that an organic FET using pentacene has high mobility (for example, see Non-Patent Document 1). However, since pentacene has a high affinity for oxygen, there is a problem that an organic FET using pentacene cannot operate stably in the atmosphere. Further, in order to obtain a stable organic FET with little variation in characteristics, a vacuum deposition method, which is a high vacuum process, is essential as a method for forming a pentacene thin film. As a method for forming a pentacene thin film, a coating method, for example, a method of forming a pentacene crystal in a dilute solution of trichlorobenzene has been proposed (for example, see Patent Document 1). It is difficult to obtain a stable organic FET. The deterioration and variation of the organic FET characteristics are caused by crystal grain boundaries.

  Thus, a liquid crystal organic semiconductor utilizing liquid crystallinity has been proposed as a low molecular weight organic semiconductor material that is not affected by crystal grain boundaries and is soluble in an organic solvent (see, for example, Non-Patent Document 2). The mobility of the liquid crystal organic semiconductor can be increased by orientation control using a known method. However, the mobility value is low and insufficient. In general, a liquid crystal organic semiconductor is in a crystalline state at room temperature because the temperature range showing a liquid crystal phase is higher than room temperature. For this reason, the liquid crystal organic semiconductor exhibits stable carrier transportability in the temperature range showing the liquid crystal phase, but does not exhibit stable carrier transportability at room temperature due to the influence of crystal grain boundaries (for example, see Non-Patent Document 3).

  As an organic transistor using a polymer organic semiconductor material, for example, an organic FET using polythiophene is disclosed (for example, see Patent Document 2). The organic FET is excellent in film formability in that a thin film can be easily formed by solution coating, but has low mobility and on / off ratio (on current / off current). Further, since the ionization potential is relatively low and the device is susceptible to doping in the air, the deterioration of the device in the air is large. Many attempts have been made to improve the stability of polythiophene (for example, see Non-Patent Document 4), but an organic FET having sufficient characteristics has not been obtained.

  From the viewpoint of increasing the mobility of organic FETs, low molecular organic semiconductor materials are generally denser in packing between molecules than polymer organic semiconductor materials, and the overlap between molecular orbitals is larger. This is advantageous. On the other hand, from the viewpoint of the film-forming property of the FET element manufacturing process, generally, a high molecular organic semiconductor material has better solubility in a solvent than a low molecular organic semiconductor material, and crystal grains This is advantageous because it is not affected by variations in the characteristics of the organic FET caused by the field. As described above, although many developments such as low molecular weight and high molecular weight materials have been made as organic semiconductor materials, each has advantages and disadvantages, and has led to the development of organic semiconductor materials that sufficiently satisfy various characteristics. Not in.

  Industrially, even with low molecular weight organic semiconductor materials, as with high molecular weight organic semiconductor materials, it is possible to form films by various printing methods, and good organic materials with little variation without strict control of film formation conditions. Development of a material capable of manufacturing an FET is strongly desired, but there are few reports (for example, see Patent Document 1, Non-Patent Document 5, and Non-Patent Document 6).

Generally, a low molecular weight organic semiconductor material can be formed into a good thin film by a vacuum deposition method, and the performance of the obtained organic FET is stable. However, according to the solution coating method, it is easy to form independent small plate crystals, and it is very difficult to obtain a continuous film (continuous uniform thin film) of large crystals with little influence of grain boundaries. The performance of the organic FET is remarkably deteriorated, the performance of the organic FET does not appear at all, and often does not function as a transistor at all. In addition, the yield decreases.

  Patent Document 3 discloses a 1,4-dithienylbenzene derivative as one of liquid crystalline organic semiconductor materials. Although an organic FET manufactured by a vacuum deposition method has been reported, it is manufactured by a solution coating method. Organic FETs are not described and there are no reports.

Non-Patent Document 7 describes the synthesis of methylene-bridged bis (2-thienyl) benzene and its polymerization, but it has not been studied as an organic semiconductor material.
Non-Patent Document 8 describes various derivatives as organic semiconductor materials. In general, a structure in which oxygen is bonded to methylene carbon having a methylene bridge structure is ionized according to electronic state calculation (PC GAMESS). In the case of an FET having a large potential and gold as a source / drain electrode, the hole injection barrier becomes large, so that it tends to be unsuitable as a material for a P-type organic transistor.

Organic transistor types can be broadly classified into top contact types and bottom contact types. As the performance of the FET, the top contact type often has better performance from the viewpoint of excellent carrier injection efficiency. However, in order to manufacture a large area organic FET at low cost, a bottom contact type material that can be manufactured simply by solution-coating an organic transistor material on the source and drain electrode portions previously manufactured on the base substrate. Is suitable. Therefore, a material capable of exhibiting sufficient FET performance even with a bottom contact type by solution coating is desired.
JP 2005-281180 A JP-A-63-076378 JP 2007-59558 A Yen-Yi Lin., “IEEE Transaction on Electron Device”, (USA), 1997, Vol.44 No8, p.1325 M. Funahashi and J. Hanna, “Japanese Journal of Applied Physics”, 1999, Vol. 38, p.L132-135 M. Funahashi, “Applied Physics Letters”, (USA), 1998, Vol.73 No.25, p.3733-3735 IAIN MCCULLOCH, MARTIN HEENEY et al., “NATURE MATERIALS”, April 2006, Vol.5, p.328-333 DAE HO SONG, MIN HEE CHOI, JUNE YOUNG KIM, AND JIN JANG, “APPLIED PHYSICS LETTERS 90”, (USA), 2007, 053504 Marcia M. Payne, Sean R. Parkin, John E. Anthony, Chung-Chen Kou, and Thomas N. Jackson, “Journal of the American Chemical Society”, (USA), 2005, 127, p.4986-4987 Xiaoyong M. Hong and David M. Collard, “Polymer Preprints”, 2000, 41 (1), 189 Chunchang Zhao, Yong Zhang, and Man-Kit Ng, “The Journal of Organic Chemistry”, American Chemical Society Published on Web 07/18/2007

  An object of the present invention is to provide a compound having high mobility, resistance to oxygen and moisture, easy formation of a thin film, and excellent film forming properties. In particular, it is an object of the present invention to provide a compound capable of forming a stable thin film by a solution coating method in the manufacture of a bottom contact type organic transistor.

  The present invention also relates to an organic transistor using the compound, particularly an organic transistor using the compound, which has a large on-off ratio, a low threshold voltage, and operates stably in the atmosphere and has little deterioration with time. It is an object to provide a transistor, particularly an organic FET.

  According to the organic semiconductor material of a compound having a specific structure with high molecular planarity, the present inventors can easily form a film by a solution coating method and exhibit stable performance even in a low molecular system. The inventors have found that an organic transistor can be manufactured, and have completed the present invention.

The present invention has the following configuration.
[1] A compound represented by the following formula (I).

(In formula (I), R ¹ and R ² are each independently hydrogen, halogen, cyano, or alkyl having 1 to 30 carbon atoms;
R ³ and R ⁴ are each independently halogen, cyano, alkyl having 1 to 30 carbons or phenyl, and in the phenyl, any hydrogen may be replaced by halogen, cyano or alkyl having 1 to 30 carbons. Often,
A is a tetravalent group derived by removing any four hydrogen atoms from the benzene ring, a tetravalent group derived by removing any four hydrogen atoms from the naphthalene ring, or any four groups from the anthracene ring. In the anthracene ring, the 9-position and 10-position hydrogens may be replaced with alkyl having 1 to 30 carbon atoms,
Ar is each independently arylene or heteroarylene, and in the arylene or heteroarylene, any hydrogen may be replaced by halogen, cyano, or alkyl having 1 to 30 carbons;
In any of the above alkyl groups having 1 to 30 carbon atoms, any hydrogen may be replaced with a halogen, and any —CH ₂ — represents —O—, —S—, —COO—, —OCO—, —CH =
CH— or —C≡C— may be replaced, and any carbon may be replaced with silicon;
j and k are independently integers of 0 to 3. )
[2] In the above formula (I), Ar is independently a heteroarylene represented by the following formula (II), the following formula (III), or the following formula (IV). The compound according to Item.

(In the formulas (II), (III) and (IV), R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently hydrogen, halogen, cyano or alkyl having 1 to 20 carbon atoms, In the alkyl having 1 to 20 carbon atoms, arbitrary hydrogen may be replaced by halogen, and arbitrary —CH ₂ — represents —O—, —S—, —COO—, —OCO—, —CH═CH—. Or -C≡C- and any carbon may be replaced by silicon.)
[3] In the formula (I), R ³ and R ⁴ are each independently alkyl having 1 to 20 carbons or phenyl,
In the alkyl having 1 to 20 carbon atoms, arbitrary —CH ₂ — is —O—, —S—, —COO.
-, -OCO-, -CH = CH- or -C≡C- may be substituted,
In the phenyl, any hydrogen may be replaced with halogen, cyano, or alkyl having 1 to 30 carbons. In the alkyl having 1 to 30 carbons, any hydrogen may be replaced with halogen. —CH ₂ — represents —O—, —S—, —COO—, —OCO.
-, -CH = CH- or -C≡C-, and any carbon may be replaced by silicon;
Ar is each independently a heteroarylene represented by the following formula (II):
The compound as described in the above item [1], wherein j and k are 1.

(In the formula (II), R ⁵ is hydrogen or alkyl having 1 to 20 carbon atoms,
In the alkyl, any —CH ₂ — represents —O—, —S—, —COO—, —OCO—, —
It may be replaced by CH═CH— or —C≡C—. )
[4] In the formula (I), R ¹ and R ² are each independently hydrogen or alkyl having 1 to 20 carbons,
R ³ and R ⁴ are each independently alkyl or phenyl having 1 to 20 carbon atoms,
In the phenyl, any hydrogen may be replaced with alkyl having 1 to 20 carbons,
In any alkyl group having 1 to 20 carbon atoms, any —CH ₂ — represents —O— or —S.
-, -COO-, -OCO-, -CH = CH- or -C≡C- may be substituted,
The compound according to item [1], wherein j and k are 0.

  [5] The compound according to [1], which is represented by the following formula (I-3).

(In Formula (I-3), R ³ and R ⁴ are each independently alkyl having 1 to 20 carbon atoms, and in the alkyl having 1 to 20 carbon atoms, any —CH ₂ — is —O—, -S-, -COO
-, -OCO-, -CH = CH-, or -C≡C- may be substituted. )
[6] The compound according to item [1], which is represented by the following formula (I-4) or the following formula (I-5).

(In the formulas (I-4) and (I-5), R ³ and R ⁴ are each independently alkyl having 1 to 20 carbon atoms, and in the alkyl having 1 to 20 carbon atoms, any —CH ₂ -Is -O-,
-S-, -COO-, -OCO-, -CH = CH-, or -C≡C- may be substituted. )
[7] The compound of the above-mentioned [1], which is represented by the following formula (I-6) or the following formula (I-7).

(In the formulas (I-6) and (I-7), R ¹² and R ¹³ are each independently hydrogen or alkyl having 1 to 20 carbons,
R ³ and R ⁴ are each independently a C1-20 alkyl or phenyl,
In the phenyl, any hydrogen may be replaced with alkyl having 1 to 20 carbons,
In any alkyl group having 1 to 20 carbon atoms, any —CH ₂ — represents —O— or —S.
-, -COO-, -OCO-, -CH = CH-, or -C≡C- may be substituted. )
[8] A thin film formed from the compound according to any one of [1] to [7].

[9] An organic semiconductor film comprising the thin film according to [8].
[10] An organic transistor comprising the organic semiconductor film according to [9].
[11] An organic field effect transistor comprising a gate electrode, a source electrode, a drain electrode, a gate insulating film, and the organic semiconductor film according to [9].

  The compound of the present invention is useful as an organic semiconductor material because it has high mobility, is resistant to oxygen and moisture, is easy to form a thin film, and has excellent film formability. According to the compound of the present invention, a stable thin film can be formed by a solution coating method particularly in the production of a bottom contact type organic transistor.

  In addition, an organic transistor using the compound of the present invention, particularly an organic FET, has excellent characteristics such as a large on / off ratio, a low threshold voltage, a stable operation in the atmosphere, and a small deterioration with time. Furthermore, the organic transistor using the compound of the present invention, particularly the organic FET, has little variation in the characteristics.

Hereinafter, the present invention will be specifically described.
<Compound of the present invention>
The compound of the present invention is represented by the following formula (I).

In the formula (I), R ¹ and R ² are each independently hydrogen, halogen, cyano, or alkyl having 1 to 30 carbons, preferably each independently hydrogen or alkyl having 1 to 20 carbons, Preferred is hydrogen or alkyl having 1 to 15 carbons, and particularly preferred is hydrogen or alkyl having 1 to 10 carbons. Specific examples of the halogen include F or Cl, and F is particularly preferable.

In the alkyl, any hydrogen may be replaced by halogen, and any —CH ₂ — may be —O—, —S—, —COO—, —OCO—, —CH═CH— or —C≡C—. And any carbon may be replaced by silicon. Preferably, any —CH ₂ — is —O—, —S—, —COO—, —OCO—, —CH═CH— or —C≡C.
It may be replaced with-. Specific examples of halogen that can be substituted for any hydrogen in the alkyl include F or Cl, and F is particularly preferred.

  Specific examples of the alkyl include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl and the like. Methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl are preferred, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, Nonyl and decyl are particularly preferred.

In the formula (I), R ³ and R ⁴ are each independently halogen, cyano, alkyl having 1 to 30 carbons or phenyl, preferably each independently alkyl having 1 to 20 carbons or phenyl, and more Preferably it is a C1-C15 alkyl or phenyl, Most preferably, it is a C1-C10 alkyl. Specific examples of the halogen include F or Cl, and F is particularly preferable.

In the alkyl, any hydrogen may be replaced by halogen, and any —CH ₂ — may be —O—, —S—, —COO—, —OCO—, —CH═CH— or —C≡C—. And any carbon may be replaced by silicon. Preferably, any —CH ₂ — is —O—, —S—, —COO—, —OCO—, —CH═CH— or —C≡C.
It may be replaced with-. Specific examples of halogen that can be substituted for any hydrogen in the alkyl include F or Cl, and F is particularly preferred.

  Specific examples of the alkyl include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl. , Methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl Decyl is particularly preferred.

  In the phenyl, any hydrogen may be replaced with halogen, cyano, or alkyl having 1 to 30 carbons, and preferably may be replaced with alkyl having 1 to 20 carbons, more preferably 1 to 15 carbons. And may be particularly preferably substituted with an alkyl having 1 to 10 carbon atoms. Specific examples of the halogen that can be substituted for any hydrogen in the phenyl include F or Cl, and F is particularly preferable.

In the alkyl substituted with any hydrogen in the phenyl, any hydrogen may be substituted with halogen, and any —CH ₂ — may be —O—, —S—, —COO—, —OCO.
-, -CH = CH- or -C≡C- may be substituted, and any carbon may be replaced by silicon. Preferably, any —CH ₂ — is —O—, —S—, —COO—, —
OCO-, -CH = CH- or -C≡C- may be substituted. Specific examples of halogen that can be substituted for any hydrogen in the alkyl include F or Cl, and F is particularly preferred.

  Specific examples of alkyl substituted for any hydrogen in the phenyl include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl , Octadecyl, nonadecyl, icosyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl are preferred, methyl, ethyl, propyl, butyl, Pentyl, hexyl, heptyl, octyl, nonyl and decyl are particularly preferred.

  In formula (I), A represents a tetravalent group derived by removing any four hydrogens from the benzene ring, a tetravalent group derived by removing any four hydrogens from the naphthalene ring, or anthracene A tetravalent group derived by removing any 4 hydrogen atoms from the ring, preferably a tetravalent group derived by removing any 4 hydrogen atoms from the benzene ring or any 4 groups from the naphthalene ring And a tetravalent group derived by removing any four hydrogens from the naphthalene ring.

  In the anthracene ring, the 9-position and 10-position hydrogens may be replaced with alkyl having 1 to 30 carbon atoms, preferably may be replaced with alkyl having 1 to 20 carbon atoms, more preferably 1 to 1 carbon atoms. It may be substituted with 15 alkyls, and particularly preferably may be substituted with alkyl having 1 to 10 carbon atoms.

In the alkyl substituted with the 9th and 10th hydrogens in the anthracene ring, any hydrogen may be replaced with a halogen, and any —CH ₂ — represents —O—, —S—, —
COO—, —OCO—, —CH═CH— or —C≡C— may be substituted, and any carbon may be substituted with silicon. Preferably, any —CH ₂ — is —O—, —S.
-, -COO-, -OCO-, -CH = CH-, or -C≡C- may be substituted. Specific examples of halogen that can be substituted for any hydrogen in the alkyl include F or Cl, and F is particularly preferred.

Specific examples of the alkyl substituted for the 9th and 10th hydrogens in the anthracene ring include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, Examples include pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methyl, ethyl , Propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl are particularly preferred.

In formula (I), Ar is each independently arylene or heteroarylene, preferably heteroarylene.
In the arylene or the heteroarylene, any hydrogen may be replaced with halogen, cyano, or alkyl having 1 to 30 carbons, preferably, alkyl having 1 to 20 carbons, more preferably It may be substituted with alkyl having 1 to 15 carbon atoms, and particularly preferably may be substituted with alkyl having 1 to 10 carbon atoms. Specific examples of halogen that can be substituted for any hydrogen in the arylene or heteroarylene include F or Cl, and F is particularly preferable.

In the alkyl substituted for any hydrogen in the arylene or heteroarylene, any hydrogen may be replaced with a halogen, and any —CH ₂ — may be —O—,
-S-, -COO-, -OCO-, -CH = CH- or -C≡C- may be substituted, and any carbon may be replaced by silicon. Preferably, any —CH ₂ — is —
O—, —S—, —COO—, —OCO—, —CH═CH— or —C≡C— may be substituted. Specific examples of halogen that can be substituted for any hydrogen in the alkyl include F or Cl, and F is particularly preferred.

  Specific examples of alkyl substituted for any hydrogen in the arylene or heteroarylene include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl Hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl are preferred, methyl, ethyl, Particularly preferred are propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl and decyl.

In formula (I), j and k are each independently an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 1, and particularly preferably 0.
Ar in the formula (I) is preferably independently a heteroarylene represented by the following formula (II), the following formula (III) or the following formula (IV), and each independently represents the following formula (II). It is more preferable that it is heteroarylene represented by these.

In the formulas (II), (III) and (IV), R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently hydrogen, halogen, cyano or alkyl having 1 to 20 carbon atoms, preferably Are each independently hydrogen or alkyl having 1 to 20 carbons, more preferably alkyl having 1 to 15 carbons, and particularly preferably alkyl having 1 to 10 carbons. Specific examples of the halogen include F or Cl, and F is particularly preferable.

In the alkyl, any hydrogen may be replaced by halogen, and any —CH ₂ — may be —O—, —S—, —COO—, —OCO—, —CH═CH— or —C≡C—. And any carbon may be replaced by silicon. Preferably, any —CH ₂ — in the alkyl may be replaced with —O—, —S—, —COO—, —OCO—, —CH═CH— or —C≡C—. Specific examples of halogen that can be substituted for any hydrogen in the alkyl include F or Cl, and F is particularly preferred.

  Specific examples of the alkyl include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl. , Methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl Decyl is particularly preferred.

In the present invention, when —CH ₂ — in alkyl is replaced by —O— or the like, —O—O—, —O—S—, —S—O—, — The presence of S—S—S—, —COOO—, —OOOC—, —COO—OOC— or —OCO—OCO— is not preferable because the stability of the compound is impaired. Specifically, when R ¹ is alkyl having 1 carbon (methyl), —CH ₂ — does not exist, and thus cannot be replaced with —O— or the like. For example, when R ¹ is alkyl having 3 carbon atoms (—CH ₂ —CH ₂ —CH ₃ ), —CH ₂ — in the alkyl can be replaced with —O— or the like. ¹ can be —CH ₂ —O—CH ₃ . Similarly, when R ¹ is alkyl having 4 or more carbon atoms,
Arbitrary —CH ₂ — in the alkyl is —CH ₂ — which is further adjacent to —CH ₂ —.
Unless it is replaced with O- or the like, it can be replaced with -O- or the like.

  In addition, the compound of the present invention is preferably a compound represented by the following formula (I-1).

R ¹ and R ^{2 in} formula (I-1) are each independently hydrogen, halogen, cyano, or alkyl having 1 to 20 carbons.
R ³ and R ^{4 in} formula (I-1) are each independently alkyl or phenyl having 1 to 20 carbon atoms, and in the phenyl, any hydrogen is halogen, cyano or alkyl having 1 to 20 carbon atoms. It may be replaced.

R ¹⁰ and R ^{11 in} formula (I-1) are each independently hydrogen or alkyl having 1 to 20 carbons, and in the alkyl having 1 to 20 carbons, any hydrogen may be replaced by halogen. Well, any —CH ₂ — is —O—, —S—, —COO—, —OCO—, —CH═
CH— or —C≡C— may be replaced, and any carbon may be replaced with silicon.

  A in formula (I-1) is a tetravalent group derived by removing any four hydrogens from the benzene ring, and a tetravalent group derived by removing any four hydrogens from the naphthalene ring Alternatively, it is a tetravalent group derived by removing any four hydrogens from the anthracene ring, and in the anthracene ring, the 9-position and 10-position hydrogens may be replaced with alkyls having 1 to 20 carbon atoms.

In any of the above alkyl groups having 1 to 20 carbon atoms, any hydrogen may be replaced by a halogen, and any —CH ₂ — represents —O—, —S—, —COO—, —OCO—, —CH =
CH— or —C≡C— may be replaced, and any carbon may be replaced with silicon.

  In addition, the compound of the present invention is preferably a compound represented by the following formula (I-2).

R ¹ and R ² in the formula (I-2) are each independently hydrogen or alkyl having 1 to 20 carbons.
R ³ and R ^{4 in} formula (I-2) are each independently alkyl or phenyl having 1 to 20 carbon atoms, and in the phenyl, any hydrogen is halogen, cyano or alkyl having 1 to 20 carbon atoms. It may be replaced.

  A in formula (I-2) is a tetravalent group derived by removing any 4 hydrogen atoms from the benzene ring, or a tetravalent group derived by removing any 4 hydrogen atoms from the naphthalene ring. Alternatively, it is a tetravalent group derived by removing any four hydrogens from the anthracene ring, and in the anthracene ring, the 9-position and 10-position hydrogens may be replaced with alkyls having 1 to 20 carbon atoms.

In any of the above alkyl groups having 1 to 20 carbon atoms, any hydrogen may be replaced by a halogen, and any —CH ₂ — represents —O—, —S—, —COO—, —OCO—, —CH =
CH— or —C≡C— may be replaced, and any carbon may be replaced with silicon.

  In addition, examples of the compound of the present invention include compounds represented by the following formula (I-3), the following formula (I-4), or the following formula (I-5).

In formulas (I-3), (I-4) and (I-5), R ³ and R ⁴ are each independently alkyl having 1 to 20 carbons.
In the alkyl, arbitrary —CH ₂ — represents —O—, —S—, —COO—, —OCO—.
, -CH = CH- or -C≡C-.

  Specific examples of the alkyl include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl. , Methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl Decyl is particularly preferred.

  Moreover, as a compound of this invention, the compound represented by a following formula (I-6) or a following formula (I-7) is mentioned.

In formulas (I-6) and (I-7), R ¹² and R ¹³ are each independently hydrogen or alkyl having 1 to 20 carbons, preferably alkyl having 1 to 15 carbons.
In the alkyl, arbitrary —CH ₂ — represents —O—, —S—, —COO—, —OCO—.
, -CH = CH-, or -C≡C-.

  Specific examples of the alkyl include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl and the like. Methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl are preferred, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, Nonyl, decyl, undecyl and dodecyl are particularly preferred.

In formulas (I-6) and (I-7), R ³ and R ⁴ are each independently alkyl or phenyl having 1 to 20 carbons, preferably alkyl or phenyl having 1 to 15 carbons. .

In the alkyl, arbitrary —CH ₂ — represents —O—, —S—, —COO—, —OCO.
-, -CH = CH- or -C≡C- may be substituted.
Specific examples of the alkyl include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl. , Methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl Decyl, undecyl and dodecyl are particularly preferred.

In the phenyl, arbitrary hydrogen may be replaced with alkyl having 1 to 20 carbons, and preferably with alkyl having 1 to 15 carbons.
In the alkyl substituted with any hydrogen in the phenyl, any —CH ₂ — is replaced with —O—, —S—, —COO—, —OCO—, —CH═CH— or —C≡C—. May be.

  Specific examples of alkyl substituted for any hydrogen in the phenyl include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl , Octadecyl, nonadecyl, icosyl, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl are preferred, methyl, ethyl, propyl, butyl, Pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl are particularly preferred.

<Characteristics of the Compound of the Present Invention>
The compounds of the present invention have a high mobility. Also, the drain current on / off ratio (on current / off current) due to the gate voltage of the organic transistor using the compound shows a high numerical value. Therefore, the compound of the present invention has excellent properties as an organic semiconductor material.

  The compound of the present invention has an easy film forming process and is excellent in film formability. Therefore, various thin film forming methods can be applied. Even when a solution coating method is applied in particular, a uniform and continuous thin film can be formed suitably. Therefore, by using the compound of the present invention, it is possible to produce an organic semiconductor film having high mobility and an organic transistor having excellent characteristics using the organic semiconductor film. In particular, when a solution coating method is applied, an organic transistor or the like having a large area, low cost, and excellent characteristics can be realized.

In addition, the compound of the present invention has a high melting point, and an organic semiconductor film formed from the compound, an organic transistor using the same, and the like are excellent in heat resistance.
In the compound of the present invention, the mobility tends to increase as the number of A rings in formula (I) increases. That is, a tetravalent group derived by removing any four hydrogens from a naphthalene ring rather than a tetravalent group derived by removing any four hydrogens from a benzene ring, any four from a naphthalene ring The mobility tends to be higher when a tetravalent group derived by removing any four hydrogens from the anthracene ring is used than by a tetravalent group derived by removing any hydrogen.

On the other hand, the stability to oxygen and light tends to decrease in the case of a tetravalent group derived by removing any four hydrogens from the anthracene ring. Therefore, A in formula (I) is a tetravalent group derived by removing any four hydrogens from the benzene ring or a tetravalent group derived by removing any four hydrogens from the naphthalene ring. preferable.

Although the optimum value of mobility differs depending on the application, the mobility (μ ^FET ) generally required for organic semiconductor materials is 10 ⁻⁴ cm ² / V · s or more.
The mobility (μ ^FET ) is obtained by using the following equation (ii) using a transfer characteristic curve obtained by fixing the drain voltage (V _D ) and changing the gate voltage (V _G ). Can do.

In formula (ii), C _in is the capacitance per unit area of the gate insulating film (F / cm ² ), I _D is the drain current (A), L is the channel length (cm), and W is the channel width (cm). , V _TH is a threshold voltage (V). In the present application, the mobility (μ ^FET ) is a value obtained by a measurement method in Examples described later.

<Method for producing compound of the present invention>
The compound represented by the above formula (I) of the present invention is synthesized, for example, by a known method by synthesizing a compound represented by the following formula (I) ′ and dissolving the compound in diethylene glycol under a nitrogen stream. The solution can be prepared by adding potassium hydroxide and hydrazine monohydrate and reacting with heating and stirring. Reaction temperature is 50-150 degreeC normally, Preferably it is 100-150 degreeC, More preferably, it is 140-150 degreeC. The reaction pressure is usually atmospheric pressure. The reaction time is usually 6 to 48 hours, preferably 24 to 48 hours, more preferably 45 to 48 hours.

In the formula (I) ′, R ¹ , R ² , R ³ , R ⁴ , A, Ar, j, k are the same as those in the formula (I).
R ¹ , R ² , R ³ , R ⁴ , A, Ar, etc. can be set as desired by appropriately selecting the raw materials for synthesizing the compound represented by the above formula (I) ′. .

Specific examples of the method for producing the compound of the present invention include indaceno [1,2-b:
5,6-b ′] dithiophene-4,9-dione was synthesized and a solution of indaceno [1,2-b: 5,6-b ′] dithiophene-4,9-dione dissolved in diethylene glycol was converted into a nitrogen stream. Potassium hydroxide and hydrazine monohydrate were added under the reaction, and the mixture was reacted by heating and stirring to thereby produce indaceno [1,2-b: 5,6-b ′] dithiophene (6IDDT6 represented by the following formula (A). ).

  Hereinafter, a method for producing indaceno [1,2-b: 5,6-b ′] dithiophene (6IDDT6) will be described in detail. Indaceno [1,2-b: 5,6-b ′] dithiophene (6IDDT6) can be synthesized, for example, through the following steps i) to vii).

  i) Synthesis of compound (1)

  A normal butyllithium / hexane solution is added to a solution of 2-hexylthiophene in tetrahydrofuran and allowed to react. Then, a compound (1) is obtained by adding tributyltin chloride and making it react.

  ii) Synthesis of compound (2)

  A solution of 5,6-dibromoxylene dissolved in tetrahydrofuran is reacted by adding a saturated aqueous potassium permanganate solution while heating under reflux in a nitrogen stream to obtain compound (2).

  iii) Synthesis of compound (3)

Compound (3) is obtained by adding thionyl chloride to a solution obtained by dissolving compound (2) obtained in (ii) above in methanol.
iv) Synthesis of compound (4)

  Triphenylphosphine and N, N-dimethylformamide were added to a solution of the compound (1) obtained in i) and the compound (3) obtained in iii) in toluene, and then nitrogen gas was used. And deaerate. Thereafter, tetrakistriphenylphosphine palladium is added and reacted to obtain compound (4).

  v) Synthesis of compound (5)

Compound (5) is obtained by adding sodium hydroxide and water to a solution obtained by dissolving compound (4) obtained in iv) above in ethanol.
vi) Synthesis of compound (6)

Oxalyl dichloride (2.7 g, 14 mmol) and N, N-dimethylformamide (2 ml) are added to and reacted with a solution of the compound (5) obtained in v) above in chloroform. Furthermore, a compound (6) is obtained by adding aluminum chloride and making it react.

  vii) Synthesis of compound (7)

  Compound (7) is obtained by adding potassium hydroxide and hydrazine monohydrate to a solution of compound (6) obtained in vi) above in diethylene glycol and reacting them in a nitrogen stream.

<Thin film>
The thin film of the present invention is formed from a novel compound having a molecular structure with high planarity as described above. The thickness of the thin film can be appropriately determined according to the purpose. Various known film forming methods can be applied to the thin film forming method. For example, a vacuum deposition method and a solution coating method can be mentioned. In particular, when a solution coating method is applied, a large-area thin film can be efficiently formed. In addition, the manufacture of an organic transistor such as an organic FET including a thin film forming process by a solution coating method contributes to simplification of the manufacturing process and improvement of manufacturing efficiency. In addition, since it can be manufactured without the need for a high vacuum process, it contributes to an increase in area, cost reduction, and improvement in response to process changes.
Furthermore, since it can be manufactured without the need for a high-temperature process, plastic can be used as the substrate material, and flexibility can be imparted to the product, and weight reduction of the product can be achieved.

<Organic semiconductor film>
The organic semiconductor film of the present invention comprises the above thin film. Therefore, it can be formed by the same method as the thin film of the present invention. As a method for forming the organic semiconductor film, various known film forming methods can be used. Specific examples of the film forming method include 1) vacuum deposition method and 2) solution coating method.

  In the case of using the vacuum deposition method 1), a deposition substrate is set in a vacuum chamber, for example, tungsten or tantalum is used as a deposition board, an organic semiconductor material is set therein, and these are deposited under vacuum. An organic semiconductor material can be deposited by applying current to the board and heating it.

  The vapor deposition rate and film thickness of the organic semiconductor film can be confirmed and controlled as appropriate using a crystal resonator on the substrate. Further, a heater is attached to the substrate holder, and vapor deposition can be performed by controlling the substrate temperature (25 ° C. to 250 ° C.). In general, when the substrate temperature is increased, the grain size can be increased, so that a favorable organic semiconductor film having higher mobility can be formed.

  In the case of using the solution coating method of 2), specifically, any of the spin coating method, the ink jet method, the casting method, and the dipping method is used by using a solution in which the compound of the present invention is dissolved in a solvent. It may be adopted. As the solvent, either a polar solvent or a nonpolar solvent may be used.

  Specific examples of the solvent include chloroform, dichloromethane, trichloromethane, toluene, xylene, tetrahydrofuran, cyclohexylbenzene, and trichlorobenzene. Alternatively, the organic semiconductor film can be formed by directly heating and melting the compound of the present invention without dissolving in the solvent.

  After forming an organic semiconductor film using any of the above methods, an appropriate heat treatment can be performed in a vacuum or a nitrogen atmosphere to increase the molecular orientation and grain size, thereby improving the transistor performance. . In the case of the organic FET, the form of the organic semiconductor film can be confirmed by the observation result by AFM (atomic force microscope) or SEM (scanning electron microscope) and the result of X-ray diffraction.

<Organic transistor>
An organic transistor such as an organic FET can be formed using an organic semiconductor film formed from the compound of the present invention. The organic FET is generally composed of a supporting substrate such as glass or plastic, a gate electrode, a source electrode, a drain electrode, a gate insulating film, and an organic semiconductor film. As the organic semiconductor film, an organic semiconductor film formed from the compound of the present invention can be used. The thickness of the organic semiconductor film used for the organic transistor is usually 30 to 500 nm, preferably 30 to 300 nm, and more preferably 50 to 100 nm.

  The organic FET controls the voltage applied to the gate electrode, thereby inducing carriers at the interface of the organic semiconductor on the gate insulating film and controlling the current flowing through the source electrode and the drain electrode to perform a switching operation.

The organic FET includes a bottom gate-bottom contact type, a bottom gate-top contact type, and a top gate type, and any of them may be adopted. Also, vertical organic FET
May be adopted. From the viewpoint of carrier injection between the electrode and the organic semiconductor, the top contact type is easier than the bottom contact type.

  3A and 3B show cross-sectional shapes of a bottom gate-bottom contact type organic FET and a bottom gate-top contact type organic FET, respectively. Each of these organic FETs includes a source electrode 1, a drain electrode 2, a gate electrode 3, an organic semiconductor film 4, and a gate insulating film 5.

Examples of the material of the gate electrode include Al, Ta, Mo, Nb, Cu, Ag, Au, Pt, In, Ni, Nd, Cr, polysilicon, amorphous silicon, highly doped silicon, tin oxide, indium oxide, and the like. Alternatively, an inorganic material such as indium tin oxide (ITO) or an organic material such as a doped conductive polymer may be used, and any of them may be used. The material of the gate insulating film is SiO ₂ , SiN
Inorganic materials such as Al ₂ O ₃ or Ta ₂ O ₅ and polymer materials such as polyimide or polycarbonate can be employed.

  The surface of the gate insulating film can be subjected to a known surface treatment such as HMDS treatment (hexamethyldisilazane treatment) or OTS treatment (octadecyltrichlorosilane treatment). When HMDS or OTS treatment is performed, generally, the crystal grain size, crystallinity, and molecular orientation of the organic transistor layer are increased. As a result, the mobility and on / off ratio are improved, and the threshold voltage is increased. There is a tendency to decrease.

  As a material for the source electrode and the drain electrode, the same kind of material as that for the gate electrode can be used, and the material may be the same as or different from the material for the gate electrode. In order to increase the carrier injection efficiency, these electrodes may be subjected to surface treatment. For example, there is a surface treatment using a sulfur compound.

  The organic FET can also be used as a liquid crystal display element or an EL element. In addition, when an organic FET measurement cell containing a thin film of a compound is prepared and the current / voltage curve between the source and drain electrodes is measured while changing the gate voltage, the field effect mobility can be obtained from the drain current / gate voltage curve. Can do. Furthermore, it is possible to observe the on / off operation of the drain current due to the gate voltage.

The organic FET is excellent in each characteristic because a film formed from the compound of the present invention is used as an organic semiconductor film. For example, the organic FET has a high carrier mobility, usually 10 ⁻³ cm ² / V · s or more, preferably 10 ⁻² cm ² / V · s or more, and particularly preferably 10 ⁻¹ cm ^2. / V · s or more. Although an upper limit is not specifically limited, It is 10 cm < ² > / V * s or less. Further, the organic FET has a low threshold voltage, usually 20 V or less, preferably 10 V or less, and particularly preferably 5 V or less. Although a lower limit is not specifically limited, It is -20V or more. The organic FET has a large on / off ratio, usually 10 ² or more, preferably 10 ³ or more, and particularly preferably 10 ⁵ or more. The upper limit is not particularly limited, but is 10 ⁸ or less. Furthermore, the organic FET is also excellent in heat resistance.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.
Identification of the synthesized compound was performed by nuclear magnetic resonance spectrum ( ¹ H-NMR, instrument used: Vari.
an Unity 500 (500 MHz), solvent: CDCl ₃ ).

[Example 1]
<Synthesis of Compound (A)>
Indaceno [1,2-b: 5,6-b ′] dithiophene

The above compound (A) was synthesized as follows (i) to (vii).
(I) Synthesis of compound (1)

  2-Hexylthiophene (6.8 g, 40 mmol) was dissolved in tetrahydrofuran and cooled to -78 ° C. To this tetrahydrofuran solution, 2.6M normal butyl lithium / hexane solution (8.9 ml, 60 mmol) was added dropwise and reacted at room temperature for 4 hours.

  Then, it cooled again to -78 degreeC, tributyltin chloride (16 ml, 60 mmol) was added, and it was made to react at room temperature for 12 hours. After the reaction, the solvent was distilled off, 300 ml of water was added, and the organic layer was extracted with chloroform. The organic layer was dried over magnesium sulfate, filtered and concentrated. This concentrated liquid was purified by silica gel chromatography (mobile phase hexane) to obtain Compound (1) (colorless transparent liquid, 14 g, yield 83%).

  (Ii) Synthesis of compound (2)

  5,6-Dibromoxylene (10 g, 38 mmol) was dissolved in tetrahydrofuran. While this solution was heated to reflux under a nitrogen stream, 200 ml of a saturated aqueous potassium permanganate solution was added dropwise. It was then filtered and cooled in an ice bath. Thereafter, concentrated hydrochloric acid was added to adjust pH = 6. The deposited precipitate was filtered and dried to obtain compound (2) (white solid, 9.8 g, yield 80%).

  (Iii) Synthesis of compound (3)

Compound (2) (1.5 g, 4.6 mmol) obtained in (ii) above was dissolved in methanol. To this solution was added dropwise thionyl chloride (9.9 g, 83 mmol), followed by refluxing for 8 hours. After refluxing, the solvent was distilled off, 100 ml of water was added, and the organic layer was extracted with chloroform. The organic layer was dried with magnesium sulfate and filtered. After the solvent was distilled off from the obtained filtrate, the residue was purified by recrystallization (methanol) to obtain compound (3) (white solid, 1.6 g, yield 98%).

  (Iv) Synthesis of compound (4)

  The compound (1) obtained in (i) above (14 g, 34 mmol) and the compound (3) obtained in (iii) above (3.9 g, 11 mmol) were dissolved in toluene. Triphenylphosphine (0.28 g, 1.1 mmol) and N, N-dimethylformamide (30 ml) were added to this solution, and then degassed using nitrogen gas. Then, tetrakistriphenylphosphine palladium (0.39 g, 0.34 mmol) was added and reacted at 100 ° C. for 24 hours. After the reaction, the solvent was distilled off, 300 ml of water was added, and the organic layer was extracted with chloroform. The organic layer was dried over magnesium sulfate, filtered and concentrated. This concentrated solution was purified by silica gel chromatography (mobile phase chloroform: normal hexane = 1: 1) to obtain compound (4) (yellow-green solid, 2.6 g, yield 44%).

The structure of the obtained compound (4) was confirmed by ¹ H-NMR spectrum.
(V) Synthesis of compound (5)

The compound (4) (2.6 g, 4.9 mmol) obtained in (iv) above was dissolved in ethanol. To this solution was added sodium hydroxide (0.39 g, 9.9 mmol) and water (2 ml), and the mixture was refluxed for 16 hours. After refluxing, the solvent was distilled off, and a 6N aqueous hydrochloric acid solution was added to adjust pH = 6. Next, the organic layer was extracted with chloroform. The organic layer was dried over magnesium sulfate, filtered and concentrated. This concentrated solution was purified by recrystallization (normal hexane) to obtain compound (5) (yellow-green solid, 2.3 g, yield 93%).
The structure of the obtained compound (5) was confirmed by ¹ H-NMR spectrum.

  (Vi) Synthesis of compound (6)

The compound (5) (2.3 g, 4.6 mmol) obtained in the above (v) was dissolved in chloroform and cooled to 0 ° C. To this solution, oxalyl dichloride (2.7 g, 14 mmol) and N, N-dimethylformamide (2 ml) were added and reacted at room temperature for 8 hours. After the reaction, the solvent was distilled off. The solid after distillation was dissolved in chloroform and cooled to 0 ° C. Then, aluminum chloride was added and reacted at room temperature for 4 hours. After the reaction, 300 ml of water was added and the organic layer was extracted with chloroform. The organic layer was dried over magnesium sulfate, filtered and concentrated. This concentrated solution was purified by recrystallization (normal hexane) to obtain compound (6) (green solid, 1.4 g, yield 65%).
The structure of the obtained compound (6) was confirmed by ¹ H-NMR spectrum.

  (Vii) Synthesis of compound (7)

  Compound (6) (0.20 g, 0.43 mmol) obtained in (vi) above was dissolved in diethylene glycol. To this solution, potassium hydroxide (50 mg, 0.86 mmol) and hydrazine monohydrate (87 mg, 1.7 mmol) were added under a nitrogen stream and heated at 140 ° C. for 48 hours to be reacted. The reaction solution was cooled to room temperature and poured into water, and then the organic layer was extracted with chloroform. The organic layer was dried over magnesium sulfate, filtered and concentrated. This concentrated liquid was purified by silica gel chromatography (mobile phase chloroform: normal hexane = 1: 1) and recrystallization (normal hexane) to obtain compound (7) (0.10 g of white crystals, yield 53%).

<Confirmation of structure of compound (A)>
The structure of the obtained compound (7) was confirmed by ¹ H-NMR spectrum. The resulting compound (
It was confirmed that 7) was the target compound (A).

1H-NMR (CDCl3) δ: 7.48 (s, 2H), 6.79 (s, 2H), 2.
86 (t, J = 7.5 Hz, 4H), 1.74 (m, 4H), 1.42-1.39 (m, 4H), 1.34-1.31 (m, 6H), 0. 89 (t, J = 6.4, 6H).

<Thermal analysis of compound (A)>
The obtained compound (7) was subjected to thermal analysis with DSC (equipment used: Diamond DSC (trade name) manufactured by Perkin Elmer). The temperature increase rate was 10 ° C./min, and the temperature decrease rate was 5 ° C./min. An endothermic peak was observed at 152.7 ° C. and 175.2 ° C. during the temperature raising process. In the temperature lowering process, exothermic peaks were confirmed at 173.5 ° C., 142.1 ° C., and 136.5 ° C. The enthalpies at each exothermic peak were 8.50 J / g, 9.35 J / g, and 19.04 J, respectively. / G.

<Measurement of UV-VIS Absorption of Compound (A)>
The measurement was performed with an ultraviolet-visible spectrophotometer (FP-777W (trade name) manufactured by JASCO Corporation). The solution state was measured with a chloroform solution adjusted to a sample concentration of 10 ⁻⁵ mol / l, and the thin film sample was measured with a thin film sample having a thickness of 50 nm formed on quartz glass by vacuum deposition. The UV-VIS absorption spectrum is shown in FIG.

<Measurement of ionization potential of compound (A)>
The measurement was performed with a surface analyzer (AC-1 (trade name) manufactured by Riken Keiki Co., Ltd.). As a measurement sample, a thin film sample having a film thickness of 50 nm formed by vacuum deposition on a highly doped n-type Si wafer (manufactured by Semitec Co., Ltd.) with a SiO2 insulating film having a thickness of 500 nm was used. The ionization potential was 4.22 eV.

<Measurement of thin film XRD of compound (A)>
XRD measurement was performed using an X-ray diffractometer (manufactured by BRUCKER AXS, D8 (trade name)). The measurement sample was a highly doped n-type Si wafer with a SiO2 insulating film having a thickness of 500 nm (
The orientation state in the out-of-plane direction was measured using a thin film sample having a film thickness of 50 nm formed by vacuum deposition on Semitech Co., Ltd. The measurement results are shown in FIG.

[Example 2]
<Preparation of organic FET and performance measurement of FET>
(I) Preparation of organic FET Using the compound (A) obtained in Example 1 as the organic semiconductor film, SiO ₂ as the insulating film
(Thickness is 500 nm), a highly doped n-type Si wafer (manufactured by Semitec Co., Ltd.) is used as a gate electrode, Au (50 nm) is used as a source electrode and a drain electrode, and a top contact type organic FET is used. It produced (refer FIG.3 (b)).

As a method for forming an organic semiconductor film (film thickness: 50 nm) from the compound (A), a vacuum deposition method under the following conditions was used.
(Vacuum deposition conditions)
Substrate temperature: 25 ° C
Deposition rate: 0.2 Å (angstrom) / s (second)
The source electrode and drain electrode were formed by vacuum deposition using a metal mask. The channel length (L) was 200 μm and the channel width (W) was 1.5 mm.

(II) FET performance measurement
<< Measurement of mobility (μ ^FET ) and threshold voltage (V _TH ) >>
(I) above top contact type mobility of the organic FET of which are manufactured by (mu ^FET) and threshold voltage (V _TH) was determined as follows.

The measurement temperature was room temperature (25 ° C.), and the measurement environment was atmospheric.
Using a semiconductor parameter analyzer (B1500A: manufactured by Agilent Technologies), the drain voltage (V _D = −100V) is fixed, and the gate voltage (V _G ) is changed from + 20V to −100V in increments of 0.2V to transmit The characteristics were evaluated. From this transfer characteristic curve, the mobility (μ ^FET ) and the threshold voltage (V _TH ) were calculated by the above equation (ii).
As a result, mobility (μ ^FET ) = 3.6 × 10 ⁻³ cm ² / V · s and threshold voltage (V _TH )
= 4.93V. The results are shown in Table 1.

<< Calculation of on / off ratio >>
From the measured transfer characteristics under the above conditions, the absolute value of I _D | I _D |, the maximum value (| I _D ^max |
) And the minimum value (| _ID ^min |), and the ratio | _ID ^max | / | _ID ^min | was calculated as an on / off ratio. As a result, the top contact type organic FE produced in (I) above.
The on / off ratio of T was 1.0 × 10 ⁴ . The results are shown in Table 1. The on / off ratio of the organic semiconductor material is desirably 10 ³ or more.

[Example 3]
<Preparation of organic FET and performance measurement of FET>
(I) Production of Organic FET A top contact type organic FET was produced in the same manner as in Example 2 except that the surface of the insulating film was treated with HMDS. The HMDS treatment on the surface of the insulating film was performed by a dipping method (dipping time: 60 minutes, drying: 40 ° C., 15 minutes).

(II) Measurement of FET performance The performance of the top contact type organic FET produced in the above (I) was measured in the same manner as in Example 2. As a result, the mobility (μ ^FET ) = 1.4 × 10 ⁻² cm ² / V · s, the threshold voltage (V _TH ) = − 1.44 V, and the on / off ratio = 2.8 × 10 ⁶ . The results are shown in Table 1. Compared with Example 2, the mobility (μ ^FET ) and on / off ratio were improved, and the threshold voltage (V _TH ) was lowered.

[Example 4]
<Preparation of organic FET and performance measurement of FET>
(I) Preparation of organic FET Using the compound (A) obtained in Example 1 as the organic semiconductor film, SiO ₂ as the insulating film
(Thickness is 500 nm), a highly doped n-type Si wafer (manufactured by Semitec Co., Ltd.) is used as the gate electrode, and Au (50 nm) is stacked on Cr (5 nm) as the source and drain electrodes. Using this, a bottom contact type organic FET was fabricated (see FIG. 3A).

The source electrode and drain electrode were formed by vacuum deposition using a metal mask. The channel length (L) was 200 μm and the channel width (W) was 1.5 mm.
As a method for forming the organic semiconductor film from the compound (A), a solution coating method was used. In detail, the following drop cast method was used. An organic semiconductor film (film thickness: 100 to 200 nm) is formed by preparing a toluene solution of 0.5% by weight of compound (A) and dropping this solution on a substrate (substrate temperature: 50 ° C.) with a microsyringe. did. The film form of the organic semiconductor film was observed with a polarizing microscope. In particular, the crystal form and the continuity of the film in the channel portion between the source and drain were evaluated. The film morphology was a continuous film. A polarization microscope photograph of this organic semiconductor film is shown in FIG.

(II) Measurement of FET performance The performance of the bottom contact type organic FET produced in the above (I) was measured in the same manner as in Example 2. As a result, mobility (μ ^FET ) = 4.0 × 10 ⁻⁴ cm ² / V · s, threshold voltage (V _TH ) = − 2.09 V, and on / off ratio = 7.8 × 10 ⁴ . The results are shown in Table 1.

[Comparative Example 1]
<Synthesis of Compound (B)>
1,4-bis (5′-octyl-2′-thienyl) -benzene

Compound (B) was synthesized according to the method described in Patent Document 3 (Japanese Patent Laid-Open No. 2007-59558).

[Comparative Example 2]
<Preparation of organic FET and performance measurement of FET>
(I) Production of Organic FET A bottom contact type organic FET was produced in the same manner as in Example 4 except that the compound (B) was used instead of the compound (A). Further, in the same manner as in Example 4, the film form of the obtained organic semiconductor film was observed with a polarizing microscope. In particular, the crystal form and the continuity of the film in the channel portion between the source and drain were evaluated. It was a discontinuous film composed of plate-like crystals, and the continuity as a film was poor between the source and drain. A polarization microscope photograph of this organic semiconductor film is shown in FIG. The concentration of the toluene solution of the compound (B) was increased from 0.5 wt% to 2.0 wt%, but no significant change was observed in the film form, and the film was not continuous.

(II) Measurement of FET performance The performance of the bottom contact type organic FET produced in the above (I) was measured in the same manner as in Example 2. Nine organic FETs fabricated in the above (I) were evaluated, but the performance of the transistors was not observed in all organic FETs.

1 is a UV-VIS absorption spectrum of the compound (A) of Example 1. FIG. FIG. 2 is an XRD of the thin film of the compound (A) of Example 1. 3A is a schematic diagram showing a cross-sectional shape of a bottom gate-bottom contact type organic FET, and FIG. 3B is a schematic diagram showing a cross-sectional shape of the bottom gate-top contact type organic FET. is there. FIG. 4 is a polarizing micrograph of a bottom contact FET produced by a coating method using the compound (A) of Example 1. FIG. 5 is a polarizing micrograph of a bottom contact FET produced by a coating method using the compound (B) of Comparative Example 1.

Explanation of symbols

1 Source electrode 2 Drain electrode 3 Gate electrode 4 Organic semiconductor film 5 Gate insulating film

Claims (11)

A compound represented by the following formula (I).
(In formula (I), R ¹ and R ² are each independently hydrogen, halogen, cyano, or alkyl having 1 to 30 carbon atoms;
R ³ and R ⁴ are each independently halogen, cyano, alkyl having 1 to 30 carbons or phenyl, and in the phenyl, any hydrogen may be replaced by halogen, cyano or alkyl having 1 to 30 carbons. Often,
A is a tetravalent group derived by removing any four hydrogen atoms from the benzene ring, a tetravalent group derived by removing any four hydrogen atoms from the naphthalene ring, or any four groups from the anthracene ring. In the anthracene ring, the 9-position and 10-position hydrogens may be replaced with alkyl having 1 to 30 carbon atoms,
Ar is each independently arylene or heteroarylene, and in the arylene or heteroarylene, any hydrogen may be replaced by halogen, cyano, or alkyl having 1 to 30 carbons;
In any of the above alkyl groups having 1 to 30 carbon atoms, any hydrogen may be replaced with a halogen, and any —CH ₂ — represents —O—, —S—, —COO—, —OCO—, —CH =
CH— or —C≡C— may be replaced, and any carbon may be replaced with silicon;
j and k are independently integers of 0 to 3. ) The compound according to claim 1, wherein Ar in the formula (I) is each independently a heteroarylene represented by the following formula (II), the following formula (III), or the following formula (IV).
(In the formulas (II), (III) and (IV), R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently hydrogen, halogen, cyano or alkyl having 1 to 20 carbon atoms, In the alkyl having 1 to 20 carbon atoms, arbitrary hydrogen may be replaced by halogen, and arbitrary —CH ₂ — represents —O—, —S—, —COO—, —OCO—, —CH═CH—. Or -C≡C- and any carbon may be replaced by silicon.) In the formula (I), R ³ and R ⁴ are each independently alkyl or phenyl having 1 to 20 carbon atoms,
In the alkyl having 1 to 20 carbon atoms, arbitrary —CH ₂ — is —O—, —S—, —COO.
-, -OCO-, -CH = CH- or -C≡C- may be substituted,
In the phenyl, any hydrogen may be replaced with halogen, cyano, or alkyl having 1 to 30 carbons. In the alkyl having 1 to 30 carbons, any hydrogen may be replaced with halogen. —CH ₂ — represents —O—, —S—, —COO—, —OCO.
-, -CH = CH- or -C≡C-, and any carbon may be replaced by silicon;
Ar is each independently a heteroarylene represented by the following formula (II):
The compound according to claim 1, wherein j and k are 1.
(In the formula (II), R ⁵ is hydrogen or alkyl having 1 to 20 carbon atoms,
In the alkyl, any —CH ₂ — represents —O—, —S—, —COO—, —OCO—, —
It may be replaced by CH═CH— or —C≡C—. ) In the formula (I), R ¹ and R ² are each independently hydrogen or alkyl having 1 to 20 carbon atoms,
R ³ and R ⁴ are each independently alkyl or phenyl having 1 to 20 carbon atoms,
In the phenyl, any hydrogen may be replaced with alkyl having 1 to 20 carbons,
In any alkyl group having 1 to 20 carbon atoms, any —CH ₂ — represents —O— or —S.
-, -COO-, -OCO-, -CH = CH- or -C≡C- may be substituted,
The compound according to claim 1, wherein j and k are 0. The compound of Claim 1 represented by a following formula (I-3).
(In Formula (I-3), R ³ and R ⁴ are each independently alkyl having 1 to 20 carbon atoms, and in the alkyl having 1 to 20 carbon atoms, any —CH ₂ — is —O—, -S-, -COO
-, -OCO-, -CH = CH-, or -C≡C- may be substituted. ) The compound of Claim 1 represented by a following formula (I-4) or a following formula (I-5).
(In the formulas (I-4) and (I-5), R ³ and R ⁴ are each independently alkyl having 1 to 20 carbon atoms, and in the alkyl having 1 to 20 carbon atoms, any —CH ₂ -Is -O-,
-S-, -COO-, -OCO-, -CH = CH-, or -C≡C- may be substituted. ) The compound of Claim 1 represented by a following formula (I-6) or a following formula (I-7).
(In the formulas (I-6) and (I-7), R ¹² and R ¹³ are each independently hydrogen or alkyl having 1 to 20 carbons,
R ³ and R ⁴ are each independently a C1-20 alkyl or phenyl,
In the phenyl, any hydrogen may be replaced with alkyl having 1 to 20 carbons,
In any alkyl group having 1 to 20 carbon atoms, any —CH ₂ — represents —O— or —S.
-, -COO-, -OCO-, -CH = CH-, or -C≡C- may be substituted. )   The thin film formed from the compound of any one of Claims 1-7.   An organic semiconductor film comprising the thin film according to claim 8.   An organic transistor comprising the organic semiconductor film according to claim 9.   An organic field effect transistor comprising a gate electrode, a source electrode, a drain electrode, a gate insulating film, and the organic semiconductor film according to claim 9.