JP2007019294A - Organic semiconductor material, organic semiconductor film, organic semiconductor element, and organic thin film transistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic semiconductor material having high mobility and excellent stability over time, and to provide an organic thin film transistor using the organic semiconductor material.
In an organic semiconductor material having, as a partial structure, a condensed heterocyclic ring in which at least two aromatic heterocyclic rings are condensed to an aromatic hydrocarbon ring, at least one aromatic hydrocarbon ring constituting the condensed heterocyclic ring is included. An organic semiconductor material having two substituents.
[Selection figure] None

Description

  The present invention relates to an organic semiconductor material, particularly an organic semiconductor material excellent in stability over time, and an organic thin film transistor (hereinafter also referred to as TFT) using the organic semiconductor material.

  With the widespread use of information terminals, there is an increasing need for flat panel displays as computer displays. In addition, with the progress of computerization, the information provided by paper media has increased the opportunity to be provided electronically, and as a mobile display medium that is thin, light and easy to carry, electronic paper or digital The need for paper is also increasing.

  In general, in a flat display device, a display medium is formed using an element utilizing liquid crystal, organic EL, electrophoresis, or the like. In such display media, a technique using an active drive type TFT element as an image drive element has become the mainstream in order to ensure uniformity of screen brightness, screen rewrite speed, and the like. For example, in a normal computer display, these TFT elements are formed on a glass substrate, and a liquid crystal, an organic EL element and the like are sealed.

  Here, semiconductors such as a-Si (amorphous silicon) and p-Si (polysilicon) can be mainly used for the TFT element, and these Si semiconductors (and metal films as necessary) are formed into a multilayer structure. The TFT element is manufactured by sequentially forming the drain and gate electrodes on the substrate. The manufacture of such a TFT element usually requires sputtering or other vacuum manufacturing processes.

  However, in the manufacture of such a TFT element, the vacuum system manufacturing process including the vacuum chamber must be repeated many times to form each layer, and the apparatus cost and running cost have become enormous. For example, in a TFT element, it is usually necessary to repeat processes such as vacuum deposition, dope, photolithography, development, etc. many times to form each layer, and the element is formed on a substrate through several tens of processes. Yes. A plurality of types of semiconductor layers, such as p-type and n-type, are also stacked on the semiconductor portion that is the key to the switching operation. In such a conventional manufacturing method using a Si semiconductor, it is not easy to change the equipment, for example, a design change of a manufacturing apparatus such as a vacuum chamber is required in response to the need for a large display screen.

  In addition, since the formation of such a conventional TFT element using a Si material includes a process at a high temperature, the substrate material is restricted to be a material that can withstand the process temperature. Therefore, in practice, glass must be used, and when the above-described thin display such as electronic paper or digital paper is configured using such a conventionally known TFT element, the display is heavy and flexible. Products that may break due to chipping or dropping impact. These characteristics resulting from the formation of TFT elements on a glass substrate are undesirable in satisfying the need for an easy-to-carry-type thin display accompanying the progress of computerization.

  On the other hand, in recent years, organic semiconductor materials have been energetically studied as organic compounds having high charge transport properties. These compounds have been reported in many papers such as organic laser oscillation elements as discussed in Non-Patent Document 1, etc., and Non-Patent Document 2, for example, in addition to charge transport materials for organic EL elements. Application to organic TFTs is expected. If these organic semiconductor devices can be realized, there is a possibility of obtaining a semiconductor that can be made into a solution by simplifying the manufacturing process by vacuum or low-pressure deposition at a relatively low temperature and further improving the molecular structure appropriately. It is conceivable that the organic semiconductor solution is made into an ink and manufactured by a printing method including an ink jet method. Manufacturing by these low-temperature processes has been considered impossible for conventional Si-based semiconductor materials, but there is a possibility for devices using organic semiconductors, so the above-mentioned restrictions on substrate heat resistance are relaxed. For example, a TFT element may be formed on the transparent resin substrate. If a TFT element is formed on a transparent resin substrate and the display material can be driven by the TFT element, the display is lighter and more flexible than conventional ones, and will not crack even if dropped (or very difficult to break) It could be a display.

  However, as an organic semiconductor material for realizing such a TFT element, the acenes such as pentacene and tetracene disclosed in Patent Document 1 and lead disclosed in Patent Document 2 have been studied so far. Phthalocyanines including phthalocyanines, low molecular compounds such as perylene and its tetracarboxylic acid derivatives, aromatic oligomers represented by thiophene hexamers called α-thienyl or sexithiophene disclosed in Patent Document 3, There are only limited kinds of compounds such as conjugated polymers such as polythiophene, polythienylene vinylene, and poly-p-phenylene vinylene (many of which are described in Non-Patent Document 3), and novel compounds exhibiting high carrier mobility. Of semiconductor compositions using various charge transport materials It had been long-awaited.

  Patent Document 4 describes that a liquid crystalline polymer compound having, as a repeating unit, a 5-membered heterocyclic ring and a 2- or 3-fused condensed ring composed of an aromatic ring which may have a substituent is used as an organic semiconductor material. However, the carrier mobility is small, and the formed organic semiconductor film has a problem in storage stability with time.

  Patent Document 5 describes anthradithiophene and 2,8-dialkylanthrathiophene which may have a substituent. However, the carrier mobility is small, and the formed organic semiconductor film has high storage stability over time. There was a problem.

Non-Patent Document 4 describes a ladder polymer in which benzene rings and N-alkylpyrrole rings are condensed alternately. However, the carrier mobility is low, and there is a problem in the storage stability with time of the formed organic semiconductor film.
JP-A-5-55568 JP-A-4-167561 JP-A-8-264805 JP 2004-43544 A JP-A-11-95790 Science magazine 289, 599 pages (2000) Nature magazine 403, 521 pages (2000) Advanced Material Magazine 2002 No. 2 page 99 Journal of American Chemical Society, Vol. 127, pp. 614-618, 2005, Journal of American Chemical Society, Journal of American Chemical Society

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an organic semiconductor material having high mobility and excellent stability over time, and an organic thin film transistor using the organic semiconductor material Is to provide.

  The above problem could be solved by the following configuration.

(Claim 1)
In an organic semiconductor material having, as a partial structure, a condensed heterocycle in which at least two aromatic heterocycles are condensed to an aromatic hydrocarbon ring, the aromatic hydrocarbon ring constituting the condensed heterocycle has at least one substituent. An organic semiconductor material comprising:

(Claim 2)
2. The organic semiconductor material according to claim 1, wherein the organic semiconductor material has a condensed heterocycle in which at least two aromatic heterocycles are condensed to an aromatic hydrocarbon ring having a substituent as a partial structure.

(Claim 3)
The organic semiconductor material according to claim 1, wherein the aromatic heterocycle is a 5-membered ring.

(Claim 4)
The organic semiconductor material according to any one of claims 1 to 3, wherein the hetero atom constituting the 5-membered ring is at least one selected from S, N, and O.

(Claim 5)
The organic semiconductor material according to any one of claims 1 to 4, wherein the substituent substituted on the aromatic hydrocarbon ring is an alkyl group.

(Claim 6)
The organic semiconductor material according to claim 1, wherein the organic semiconductor material is represented by the following general formula (1).

[Wherein, R _{1 to} R ₅ each represents a hydrogen atom or a substituent. ]
(Claim 7)
An organic semiconductor film comprising the organic semiconductor material according to claim 1.

(Claim 8)
An organic semiconductor element comprising the organic semiconductor film according to claim 7.

(Claim 9)
An organic thin film transistor comprising the organic semiconductor element according to claim 8.

  An organic semiconductor material having high mobility and excellent storage stability with time can be provided, and an organic thin film transistor using the organic semiconductor material can be provided.

  Hereinafter, the present invention will be described in more detail.

  The organic semiconductor material of the present invention has, as a partial structure, a condensed heterocycle in which at least two aromatic heterocycles are condensed on an aromatic hydrocarbon ring, and at least 1 in the aromatic hydrocarbon ring constituting the condensed heterocycle. It has one substituent.

  Examples of the aromatic hydrocarbon ring in the organic semiconductor material include benzene, naphthalene, anthracene, etc., and the aromatic heterocyclic ring is preferably a 5-membered ring, and S, N, It is preferably at least one selected from O.

  In addition, at least one of the aromatic hydrocarbon rings constituting the condensed heterocyclic ring preferably has a substituent, and the substituent preferably has an alkyl group as a part thereof.

  Examples of the alkyl group include, for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, cyclopentyl group. And a cyclohexyl group.

  Examples of the substituent having an alkyl group as a part of the substituent include a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a dodecyloxy group, a cyclopentyloxy group, and a cyclohexyloxy group. Methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, cyclopentylthio group, cyclohexylthio group, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, Dodecyloxycarbonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group , Dodecylaminosulfonyl group, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, acetyloxy group, ethylcarbonyloxy group, butylcarbonyl Oxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, Octylcarbonylamino group, dodecylcarbonylamino group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylamine Nocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group , Dodecylureido group, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexyl Sulfonyl group, dodecylsulfonyl group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2 -An ethylhexylamino group, a dodecylamino group, a trimethylsilyl group, a triisopropylsilyl group, a phenyldiethylsilyl group, etc., or an aryl group substituted with an alkyl group as described above (for example, a phenyl group, a naphthyl group, etc.), an alkyl group Substituted heteroaryl groups (e.g., furyl, thienyl, pyridyl, pyridazyl, pyrimidyl, pyrazyl, triazyl, imidazolyl, pyrazolyl, thiazolyl, benzoimidazolyl, benzoxazolyl, quinazolyl, Phthalazyl group, etc.), heterocyclic groups substituted with alkyl groups (eg pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group etc.), arylthio groups substituted with alkyl groups (eg phenylthio group, naphthylthio group etc.), alkyl groups Is Aryloxycarbonyl groups (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), arylaminosulfonyl groups substituted with alkyl groups (eg, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), An arylacyl group substituted with an alkyl group (eg, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), an arylacyloxy group substituted with an alkyl group (eg, phenylcarbonyloxy group, etc.), an arylamide substituted with an alkyl group A group (eg, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), an arylcarbamoyl group substituted with an alkyl group (eg, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2 An arylureido group substituted with an alkyl group (eg, phenylureido group, naphthylureido group, 2-pyridylaminoureido group), an arylsulfinyl group substituted with an alkyl group (eg, phenylsulfinyl group, naphthylsulfinyl). Group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (eg, etc.), arylsulfonyl group substituted by alkyl group (eg, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), alkyl group substituted Arylamino groups (for example, anilino group, naphthylamino group, 2-pyridylamino group, etc.), arylsilyl groups substituted by alkyl groups (for example, triphenylsilyl group), and the like.

  A preferable substituent is an alkyl group, more preferably a linear alkyl group, and still more preferably a linear alkyl group having 3 to 18 carbon atoms.

  The organic semiconductor material is preferably an organic semiconductor material represented by the general formula (1).

In said general formula, R < ₁ > -R < ₅ > represents a hydrogen atom or a substituent respectively.

The substituent represented by R ₁ and R ₂ is preferably an alkyl group or a substituent having a substituent having an alkyl group in part. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, cyclopentyl group, cyclohexyl group and the like. Examples of the substituent having an alkyl group as a part of the substituent include methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, methylaminosulfonyl group, dimethylaminosulfonyl Group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbo group Group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group , A methylsulfonyl group, an ethylsulfonyl group, a butylsulfonyl group, a cyclohexylsulfonyl group, a 2-ethylhexylsulfonyl group, a dodecylsulfonyl group, or an aryl group substituted with an alkyl group as described above (for example, a phenyl group, a naphthyl group, etc.) A heteroaryl group substituted with an alkyl group (for example, furyl group, thienyl group, pyridyl group, pyridazyl group, pyrimidyl group, pyrazyl group, triazyl group, imidazo group) Group, pyrazolyl group, thiazolyl group, benzimidazolyl group, benzoxazolyl group, quinazolyl group, phthalazyl group, etc.), heterocyclic groups substituted with alkyl groups (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.) An aryloxycarbonyl group substituted with an alkyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), an arylaminosulfonyl group substituted with an alkyl group (eg, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylamino) Sulfonyl groups, etc.), aryl acyl groups substituted with alkyl groups (eg, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), arylcarbamoyl groups substituted with alkyl groups (eg, phenylamino groups). A sulfonyl group, a naphthylaminocarbonyl group, a 2-pyridylaminocarbonyl group, etc.), an arylsulfinyl group substituted with an alkyl group (for example, a phenylsulfinyl group, a naphthylsulfinyl group, a 2-pyridylsulfinyl group, etc.), an alkylsulfonyl group (for example, etc.) ), An arylsulfonyl group substituted with an alkyl group (for example, a phenylsulfonyl group, a naphthylsulfonyl group, a 2-pyridylsulfonyl group, and the like).

Moreover, as a substituent represented by R < ₃ > -R < ₅ >, it is preferable to have an alkyl group in an alkyl group or a part of substituents.

  Examples of the alkyl group include, for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, cyclopentyl group. And a cyclohexyl group.

  Examples of the substituent having an alkyl group as a part of the substituent include a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, a dodecyloxy group, a cyclopentyloxy group, and a cyclohexyloxy group. Methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, cyclopentylthio group, cyclohexylthio group, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, Dodecyloxycarbonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group , Dodecylaminosulfonyl group, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, acetyloxy group, ethylcarbonyloxy group, butylcarbonyl Oxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, Octylcarbonylamino group, dodecylcarbonylamino group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylamine Nocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group , Dodecylureido group, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexyl Sulfonyl group, dodecylsulfonyl group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2 -An ethylhexylamino group, a dodecylamino group, a trimethylsilyl group, a triisopropylsilyl group, a phenyldiethylsilyl group, etc., or an aryl group substituted with an alkyl group as described above (for example, a phenyl group, a naphthyl group, etc.), an alkyl group Substituted heteroaryl groups (e.g., furyl, thienyl, pyridyl, pyridazyl, pyrimidyl, pyrazyl, triazyl, imidazolyl, pyrazolyl, thiazolyl, benzoimidazolyl, benzoxazolyl, quinazolyl, Phthalazyl group, etc.), heterocyclic groups substituted with alkyl groups (eg pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group etc.), arylthio groups substituted with alkyl groups (eg phenylthio group, naphthylthio group etc.), alkyl groups Is Aryloxycarbonyl groups (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), arylaminosulfonyl groups substituted with alkyl groups (eg, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), An arylacyl group substituted with an alkyl group (eg, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), an arylacyloxy group substituted with an alkyl group (eg, phenylcarbonyloxy group, etc.), an arylamide substituted with an alkyl group A group (eg, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), an arylcarbamoyl group substituted with an alkyl group (eg, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2 Pyridylaminocarbonyl group, etc.), arylureido groups substituted with alkyl groups (eg, phenylureido groups, naphthylureido groups, 2-pyridylaminoureido groups, etc.), arylsulfinyl groups substituted with alkyl groups (eg, phenylsulfinyl groups, naphthylsulfinyl groups) Group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (eg, etc.), arylsulfonyl group substituted by alkyl group (eg, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), alkyl group substituted Arylamino groups (for example, anilino group, naphthylamino group, 2-pyridylamino group, etc.), arylsilyl groups substituted by alkyl groups (for example, triphenylsilyl group), and the like.

  Specific examples of the compound of the present invention are shown below, but the compound in the present invention is not limited thereto.

  By placing the organic semiconductor material of the present invention in the active layer of the organic TFT element, it is possible to provide an organic transistor element that is driven satisfactorily.

  The organic TFT device has a source electrode and a drain electrode connected by an organic semiconductor channel (active layer) on a support, a top gate type having a gate electrode on the support via a gate insulating layer, and a support on the support First, it is roughly classified into a bottom gate type having a gate electrode and having a source electrode and a drain electrode connected by an organic semiconductor channel through a gate insulating layer.

  In order to install the compound of the present invention in the active layer of the organic TFT device, it can be installed on the substrate by vacuum deposition, but a solution prepared by dissolving in an appropriate solvent and adding additives as necessary is cast coated. It is preferably installed on the substrate by spin coating, printing, ink jet method, ablation method or the like. In this case, the solvent for dissolving the organic semiconductor material of the present invention is not particularly limited as long as the organic semiconductor material can be dissolved to prepare a solution having an appropriate concentration. Specifically, diethyl ether or diisopropyl is used. Chain ether solvents such as ether, cyclic ether solvents such as tetrahydrofuran and dioxane, ketone solvents such as acetone and methyl ethyl ketone, alkyl halide solvents such as chloroform and 1,2-dichloroethane, toluene, o-dichlorobenzene, Aromatic solvents such as nitrobenzene and m-cresol, aliphatic hydrocarbon solvents such as hexane and cyclohexane, N-methylpyrrolidone, carbon disulfide and the like can be mentioned.

  In the present invention, the material for forming the source electrode, the drain electrode, and the gate electrode is not particularly limited as long as it is a conductive material. Platinum, gold, silver, nickel, chromium, copper, iron, tin, antimony lead, tantalum, Indium, palladium, tellurium, rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, tin oxide / antimony, indium tin oxide (ITO), fluorine doped zinc oxide, zinc, carbon, graphite, glassy carbon, silver paste and Carbon paste, lithium, beryllium, sodium, magnesium, potassium, calcium, scandium, titanium, manganese, zirconium, gallium, niobium, sodium, sodium-potassium alloy, magnesium, lithium, aluminum, magnesium / Copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide mixture, lithium / aluminum mixture, etc., especially platinum, gold, silver, copper, aluminum, indium, ITO And carbon are preferred. Alternatively, a known conductive polymer whose conductivity is improved by doping or the like, for example, conductive polyaniline, conductive polypyrrole, conductive polythiophene, a complex of polyethylenedioxythiophene and polystyrenesulfonic acid, or the like is also preferably used. Among them, those having low electrical resistance at the contact surface with the semiconductor layer are preferable.

  As a method for forming an electrode, a method for forming an electrode using a known photolithographic method or a lift-off method, using a conductive thin film formed by a method such as vapor deposition or sputtering using the above as a raw material, or a metal foil such as aluminum or copper There is a method of etching using a resist by thermal transfer, ink jet or the like. Alternatively, a conductive polymer solution or dispersion, or a conductive fine particle dispersion may be directly patterned by ink jetting, or may be formed from a coating film by lithography or laser ablation. Furthermore, a method of patterning an ink containing a conductive polymer or conductive fine particles, a conductive paste, or the like by a printing method such as relief printing, intaglio printing, planographic printing, or screen printing can also be used.

  Various insulating films can be used as the gate insulating layer, and an inorganic oxide film having a high relative dielectric constant is particularly preferable. Inorganic oxides include silicon oxide, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate, lead lanthanum titanate, strontium titanate, Examples thereof include barium titanate, barium magnesium fluoride, bismuth titanate, strontium bismuth titanate, strontium bismuth tantalate, bismuth tantalate niobate, and yttrium trioxide. Of these, silicon oxide, aluminum oxide, tantalum oxide, and titanium oxide are preferable. Inorganic nitrides such as silicon nitride and aluminum nitride can also be suitably used.

  Examples of the method for forming the film include a vacuum process, a molecular beam epitaxial growth method, an ion cluster beam method, a low energy ion beam method, an ion plating method, a CVD method, a sputtering method, an atmospheric pressure plasma method, and a spray process. Wet processes such as coating methods, spin coating methods, blade coating methods, dip coating methods, casting methods, roll coating methods, bar coating methods, die coating methods, and other wet processes such as printing and ink jet patterning methods, etc. Can be used depending on the material.

  The wet process is a method of applying and drying a liquid in which fine particles of inorganic oxide are dispersed in an arbitrary organic solvent or water using a dispersion aid such as a surfactant as required, or an oxide precursor, for example, A so-called sol-gel method in which a solution of an alkoxide body is applied and dried is used.

  Among these, the atmospheric pressure plasma method and the sol-gel method are preferable.

  The method for forming an insulating film by plasma film formation under atmospheric pressure is a process in which a reactive gas is discharged under atmospheric pressure or a pressure near atmospheric pressure to excite reactive gas to form a thin film on a substrate. The method is described in JP-A-11-61406, JP-A-11-133205, JP-A-2000-121804, 2000-147209, 2000-185362, etc. (hereinafter also referred to as atmospheric pressure plasma method). Accordingly, a highly functional thin film can be formed with high productivity.

  In addition, as the organic compound film, polyimide, polyamide, polyester, polyacrylate, photo radical polymerization type, photo cation polymerization type photo curable resin, or a copolymer containing an acrylonitrile component, polyvinyl phenol, polyvinyl alcohol, novolac resin, Also, cyanoethyl pullulan or the like can be used.

  As the method for forming the organic compound film, the wet process is preferable.

  An inorganic oxide film and an organic oxide film can be laminated and used together. The thickness of these insulating films is generally 50 nm to 3 μm, preferably 100 nm to 1 μm.

  Moreover, a support body is comprised with glass or a flexible resin-made sheet | seat, for example, a plastic film can be used as a sheet | seat. Examples of the plastic film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), Examples thereof include films made of cellulose triacetate (TAC), cellulose acetate propionate (CAP), and the like. Thus, by using a plastic film, the weight can be reduced as compared with the case of using a glass substrate, the portability can be improved, and the resistance to impact can be improved.

  Below, the field effect transistor using the organic thin film which consists of a semiconductor material concerning this invention is demonstrated.

  FIG. 1 shows a schematic configuration example of a field effect transistor using the organic semiconductor material of the present invention. In FIG. 2A, a source electrode 2 and a drain electrode 3 are formed on a support 6 with a metal foil or the like, an active layer 1 made of the semiconductor material of the present invention is formed between both electrodes, and an insulating layer is formed thereon. 5 is formed, and a gate electrode 4 is further formed thereon to form a field effect transistor. FIG. 6B shows an active layer 1 using an organic semiconductor, which is formed between electrodes in FIG. 6A and is formed so as to cover the entire surface of the electrode and the support using a coating method or the like. . In (c), an active layer 1 using an organic semiconductor is first formed on a support 6 by using a coating method or the like, and then a source electrode 2, a drain electrode 3, an insulating layer 5, and a gate electrode 4 are formed. Represents.

  In FIG. 4D, after forming the gate electrode 4 on the support 6 with a metal foil or the like, the insulating layer 5 is formed, and the source electrode 2 and the drain electrode 3 are formed on the metal foil or the like on the insulating layer 5. An active layer 1 made of the semiconductor material of the present invention is formed between the electrodes. In addition, the configuration as shown in FIGS.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, the embodiment of this invention is not limited to these.

Example 1
A 200 nm thick thermal oxide film was formed on a Si wafer having a specific resistance of 0.01 Ω · cm as a gate electrode to form a gate insulating layer, and then surface treatment with octyltrichlorosilane was performed. A cast film (thickness 50 nm) was formed by applying a chloroform solution of a comparative compound <1> (pentacene, used by sublimation purification of a commercially available reagent manufactured by Aldrich) using a spin coat, and drying naturally. Heat treatment was performed at 50 ° C. for 30 minutes in a nitrogen atmosphere. Furthermore, gold was deposited on the surface of this film using a mask to form source and drain electrodes. The organic TFT element of Comparative Example 1 having a width of 100 μm, a thickness of 200 nm, a channel width W = 3 mm, and a channel length L = 20 μm was prepared.

  An organic TFT device of Comparative Example 2 was produced in the same manner as Comparative Example 1, except that Comparative Compound <1> was replaced with Comparative Compound <2> (compound disclosed in JP-A No. 11-195790).

  Similarly, Comparative Example <1> was replaced with Comparative Compound <3> (compound described in JACS Magazine 2005, Vol. 127, 614-618) in the same manner as Comparative Example 1, except that Comparative Example 3 organic TFT elements were produced.

  Furthermore, organic TFT elements of Examples 1 to 3 were produced in the same manner as in Comparative Example 1 except that the comparative compound <1> was replaced with the exemplary compounds of the present invention shown in Table 1.

  As for the organic TFT elements of Comparative Examples 1 to 3 and Examples 1 to 3 manufactured as described above, the p-channel enhancement type FET showed good operating characteristics. Further, for each organic TFT element, the carrier mobility and the ON / OFF ratio (the ratio of the drain current when the gate bias is −50 V and 0 V) are obtained from the saturation region of the IV characteristics. It was.

  The obtained element was left in the atmosphere for one month, and the carrier mobility and the ON / OFF ratio were obtained again. The results are shown in Table 1.

  From the results shown in Table 1, it was found that the organic TFT element of the present invention had good characteristics as a transistor and further suppressed deterioration over time.

  In addition, the result of Comparative Example 1 using Comparative Compound <1> (pentacene) clearly shows that it is difficult to obtain a sufficient pentacene thin film functioning as an active layer in forming a thin film by coating. On the other hand, it has been found that the organic TFT element of the present invention shows good characteristics as a transistor with little deterioration over time when a thin film is formed by coating.

It is a figure which shows the structural example of the field effect transistor using organic-semiconductor material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Active layer 2 Source electrode 3 Drain electrode 4 Gate electrode 5 Insulating layer 6 Support body

Claims (9)

In an organic semiconductor material having, as a partial structure, a condensed heterocycle in which at least two aromatic heterocycles are condensed to an aromatic hydrocarbon ring, the aromatic hydrocarbon ring constituting the condensed heterocycle has at least one substituent. An organic semiconductor material comprising: 2. The organic semiconductor material according to claim 1, wherein the organic semiconductor material has a condensed heterocyclic ring in which at least two aromatic heterocyclic rings are condensed to an aromatic hydrocarbon ring having a substituent as a partial structure. The organic semiconductor material according to claim 1, wherein the aromatic heterocycle is a 5-membered ring. The organic semiconductor material according to any one of claims 1 to 3, wherein the hetero atom constituting the 5-membered ring is at least one selected from S, N, and O. The organic semiconductor material according to any one of claims 1 to 4, wherein the substituent substituted on the aromatic hydrocarbon ring is an alkyl group. The organic semiconductor material according to claim 1, wherein the organic semiconductor material is represented by the following general formula (1).

[Wherein, R _{1 to} R ₅ each represents a hydrogen atom or a substituent. ] An organic semiconductor film comprising the organic semiconductor material according to claim 1. An organic semiconductor element comprising the organic semiconductor film according to claim 7. An organic thin film transistor comprising the organic semiconductor element according to claim 8.

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