JP2006060116A - Organic thin film transistor, material therefor, field effect transistor and switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic TFT and a field effect transistor having high carrier mobility and high durability by molecularly designing an organic TFT material useful for a thin film transistor and using the obtained organic TFT material, and to provide a switching device having the organic TFT or the field effect transistor. <P>SOLUTION: The organic thin film transistor material contains a macromolecule comprising a π conjugated system structure having weight average molecular weight Mw in a range of 5,000-10,000,000, and the ratio between the Mw and number average molecular weight Mn i.e. Mw/Mn ≤3 as a partial structure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic thin film transistor material, an organic thin film transistor, a field effect transistor, and a switching element.

  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, information that has been provided on paper media in the past has become more and more electronically provided. As a mobile display medium that is thin, light, and easy to carry, electronic paper or There is a growing need for digital paper.

  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 element (TFT element) as an image drive element has become 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 liquid crystal, organic EL elements, etc. 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 tens of steps. It is normal. 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 are expected to be applied to organic laser oscillation devices and organic thin film transistors reported in many papers in addition to charge transport materials for organic EL devices (for example, Non-Patent Document 1, Non-Patent Document 1, (See Patent Document 2).

  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, organic semiconductors for realizing such TFT elements have been studied so far as acenes such as pentacene and tetracene (for example, see Patent Document 1), phthalocyanines including lead phthalocyanine, perylene and its tetra. Low molecular weight compounds such as carboxylic acid derivatives (for example, see Patent Document 2), aromatic oligomers typically represented by thiophene hexamers called α-thienyl or sexithiophene (for example, see Patent Document 3), naphthalene, Compounds in which a 5-membered heteroaromatic ring is condensed symmetrically on anthracene (for example, see Patent Document 4), mono, oligo and polydithienopyridines (for example, see Patent Document 5), polythiophene, polythienylene vinylene, poly -Conjugated polymers such as p-phenylene vinylene Etc. limited number of compounds (e.g., see Non-Patent Documents 1 to 3.) Have only in the development of the semiconductor composition using the novel charge-transporting material showing high carrier mobility has been awaited.

  In addition, in Japanese Patent Application Laid-Open No. 2003-292588, US Patent Application Publication Nos. 2003/136958, 2003/160230, and 2003/164495, “integrated circuit logic element for microelectronics and polymer TFT When is used, its mechanical durability is greatly improved and its usable life is extended.

  However, many of the semiconductor polythiophenes are oxidatively doped with ambient oxygen, and the conductivity increases, so it is considered unstable when exposed to air. As a result, the off-state current of devices made from these materials is increased, thus reducing the current on / off ratio. Therefore, many of these materials must be taken with utmost care to eliminate or minimize oxidative doping by eliminating environmental oxygen during material processing and device fabrication. This precautionary measure increases manufacturing costs, and the attractiveness of certain polymer TFTs as an economic alternative to amorphous silicon technology, especially for large area devices, is diminished. These and other disadvantages are avoided or minimized in embodiments of the present invention.

Therefore, an electronic device having a strong resistance against oxygen and a relatively high current on / off ratio is desired ", and various solutions have been proposed (for example, patents). However, the level of improvement is not satisfactory, and further improvements are desired.
JP-A-5-55568 Japanese Patent Laid-Open No. 5-190877 JP-A-8-264805 JP-A-11-195790 JP 2003-155289 A JP 2003-261655 A “Science” 289, 599 (2000) “Nature” 403, 521 (2000) Advanced Material, 2002, No. 2, page 99

  Organic TFT materials useful for thin film transistor applications are molecularly designed, and using the obtained organic TFT materials, organic TFTs, field effect transistors having high carrier mobility and high durability, and further, It is to provide a switching element having the field effect transistor.

  The above object of the present invention has been achieved by the following configurations 1 to 8.

(Claim 1)
A high molecular weight Mw in the range of 5,000 to 10,000,000 and a π-conjugated structure having a ratio Mw / Mn of Mw to number average molecular weight Mn of 3 or less as a partial structure An organic thin film transistor material containing a molecule.

(Claim 2)
A high molecular weight Mw in the range of 5,000 to 10,000,000 and a π-conjugated structure having a ratio Mw / Mn of Mw to number average molecular weight Mn of 2 or less as a partial structure An organic thin film transistor material containing a molecule.

(Claim 3)
As a partial structure, a π-conjugated structure having a weight average molecular weight Mw in the range of 5,000 to 10,000,000 and a ratio Mw / Mn of Mw to number average molecular weight Mn of 1.5 or less. An organic thin film transistor material comprising a polymer having the same.

(Claim 4)
The organic thin film transistor material according to any one of claims 1 to 3, wherein the polymer having the π-conjugated structure as a partial structure includes an aromatic heterocyclic ring as the partial structure.

(Claim 5)
The organic thin film transistor material according to claim 4, wherein the aromatic heterocycle is a 5-membered ring or a 6-membered ring.

(Claim 6)
An organic thin film transistor, wherein the organic thin film transistor material according to claim 1 is used for a channel layer.

(Claim 7)
An organic charge transporting material and a gate electrode directly or indirectly in contact with the organic charge transporting material, and by applying a charge between the gate electrode and the organic charge transporting material, the organic charge transporting property In a field effect transistor that controls the current in a material,
A field effect transistor, wherein the organic charge transporting material is the organic thin film transistor material according to any one of claims 1 to 5.

(Claim 8)
A switching element comprising the organic thin film transistor according to claim 6 or the field effect transistor according to claim 7.

  Useful for manufacturing organic thin-film transistors (hereinafter abbreviated as organic TFTs), molecular design of organic TFT materials, excellent carrier mobility, good ON / OFF characteristics, etc. using these organic TFT materials An organic TFT and a field effect transistor having transistor characteristics and high durability were obtained. Moreover, by using them, it was possible to provide a switching element with good switching characteristics.

  In the organic TFT material of the present invention, an organic TFT material useful for thin film transistor applications can be obtained by using the configuration defined in any one of claims 1 to 5.

  In addition, organic TFTs and field-effect transistors manufactured using the organic TFT material have excellent transistor characteristics such as high carrier mobility and good ON / OFF characteristics, and are highly durable. I understood it. Moreover, it turned out that the switching element produced using this organic TFT or this field effect transistor shows a favorable switching characteristic.

  In pentacene and the like that have been reported to have good TFT characteristics so far, it is known that molecules are regularly arranged while forming a π stack between molecules. However, in polythiophene such as PHT, a regular arrangement between molecules is only partially formed.

  In addition, in Patent Document 6 described above, when a specific polythiophene includes side chains arranged in a regioregular manner on a polythiophene main chain, and a thin film of about 10 nm to about 500 nm is produced from a solution containing the polythiophene, There is a description that a dense lamellar structure is formed, and the thin film is electrically conductive and efficiently moves charge carriers.

  However, when the polythiophene described above is used, the π stack is formed only partially because it is a huge polymer molecule, and there are many parts that are not related to the π stack as parts with disordered orientation. Since it exists, it was estimated that sufficient carrier mobility and ON / OFF characteristics were not obtained.

  As a result of various investigations on the above problems, the present inventors have a weight average molecular weight Mw of 5,000 to 10,000,000 as in a polymer having a π-conjugated structure as a partial structure according to the present invention. By adjusting the ratio Mw / Mn of the Mw and the number average molecular weight Mn to be 3 or less, it has an ideal molecular arrangement as found in a conventionally known pentacene. It was possible to form a coating film, and a significant improvement in TFT performance could be achieved.

  In the present invention, the polymer having the π-conjugated structure as a partial structure preferably contains an aromatic heterocycle as a partial structure, and more preferably, the aromatic heterocycle is a 5-membered ring. .

  Hereinafter, details of each component according to the present invention will be sequentially described.

<Polymer having π-conjugated structure as partial structure>
The π-based polymer according to the present invention will be described.

<< weight average molecular weight (Mw), number average molecular weight (Mn) and Mw / Mn >>
The polymer having a π-conjugated structure as a partial structure according to the present invention has a weight average molecular weight Mw in the range of 5,000 to 10,000,000, and a ratio Mw between the Mw and the number average molecular weight Mn. / Mn is 3 or less.

  Here, as a weight average molecular weight (Mw), the range of 10,000-1,000,000 is preferable, More preferably, it is the range of 10,000-500,000.

  Moreover, as a ratio (Mw / Mn) of a weight average molecular weight (Mw) and a number average molecular weight (Mn), 2 or less is preferable, More preferably, it is 1.5 or less.

  The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polymer having a π-conjugated structure as a partial structure according to the present invention were each determined using GPC (gel permeation chromatography) well known to the trader.

<< Partial structure imparting π-conjugated system >>
Examples of the partial structure that imparts the π-conjugated system to the polymer having the π-conjugated system structure according to the present invention include an aromatic heterocyclic ring (for example, a furan ring, a thiophene ring, an oxazole ring, a pyridine ring, a pyridazine ring, Pyrimidine ring, pyrazine ring, triazine ring, benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring , A phthalazine ring, a carbazole ring, a carboline ring, a diazacarbazole ring (representing a ring in which one of the hydrocarbon rings constituting the carboline ring is further substituted with a nitrogen atom)), an aromatic hydrocarbon ring ( For example, benzene ring, biphenyl ring, naphthalene ring, azulene ring, Anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, Naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene ring, pyranthrene ring, anthraanthrene ring, etc.), preferably an aromatic heterocyclic ring, more preferably 5 to 6 Member aromatic heterocycles (eg furan ring, thiophene ring, oxazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, etc. ).

  In addition, each of the above aromatic heterocyclic ring and aromatic hydrocarbon ring may have the following substituents, for example, an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group). Group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (for example, vinyl) Group, allyl group, etc.), alkynyl group (for example, ethynyl group, propargyl group, etc.), aryl group (for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group) , Acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, bif Nylyl group, etc.), aromatic heterocyclic groups (for example, furyl group, thienyl group, pyridyl group, pyridazyl group, pyrimidyl group, pyrazyl group, triazyl group, imidazolyl group, pyrazolyl group, thiazolyl group, benzoimidazolyl group, benzoxazolyl group) Group, quinazolyl group, phthalazyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxyl group (eg, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyl) Oxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxyl group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group) Group, ethyl Group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl A group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), Sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylamino group) Sulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group) Cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy) Group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethyl Nylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc. ), Carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylamino) Carbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), urea Group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, Methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl Group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group ( For example, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group) Group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon group (eg, fluoromethyl group, trifluoromethyl group, penta) Fluoroethyl group, pentafluorophenyl group, etc.), cyano group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.).

  These substituents may be further substituted with the above substituents, or a plurality thereof may be bonded to each other to form a ring.

  Among them, a preferable substituent is an alkyl group, more preferably an alkyl group having 2 to 20 carbon atoms, and particularly preferably an alkyl group having 6 to 12 carbon atoms.

  Hereinafter, although the specific example of the polymer which has (pi) conjugated system structure as a partial structure is shown, this invention is not limited to these.

<< Organic TFT, field effect transistor and switching element >>
The organic TFT, the field effect transistor and the switching element using them according to the present invention will be described. Here, the switching element is sometimes referred to as an organic TFT element depending on its usage, and is sometimes referred to as a field effect transistor element.

  The organic TFT material of the present invention can be used for a channel layer of an organic TFT or a field effect transistor, thereby providing a switching element (also referred to as a transistor device) that is driven satisfactorily. An organic TFT (organic thin film transistor) has a source electrode and a drain electrode connected by an organic semiconductor channel as a channel on a support, a top gate type having a gate electrode on a gate insulating layer thereon, and a support First, it is roughly classified into a bottom gate type having a gate electrode on a body 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 thiophene oligomer according to the present invention in the channel (also referred to as channel layer) of a switching element using an organic TFT or a field effect transistor, it can be installed on a substrate by vacuum deposition, but it can be dissolved in an appropriate solvent. The solution prepared by adding an additive as required is preferably placed on the substrate by cast coating, spin coating, printing, ink jet method, ablation method or the like.

  In this case, the solvent for dissolving the organic TFT material of the present invention is not particularly limited as long as the organic TFT 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, 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, magnesi A copper / gold mixture, a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide mixture, a lithium / aluminum mixture, etc., in particular, platinum, gold, silver, copper, aluminum, indium, ITO and carbon are preferred. Alternatively, known conductive polymers whose conductivity is improved by doping or the like, for example, conductive polyaniline, conductive polypyrrole, conductive polythiophene, a complex of polyethylenedioxythiophene and polystyrenesulfonic acid, and the like are 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, 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, JP-A-2000-147209, JP-A-2000-185362 (hereinafter referred to as atmospheric pressure). Also called 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). And a film made of cellulose triacetate (TAC), cellulose acetate propionate (CAP), or 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 formed using the organic TFT material of this invention is demonstrated.

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

  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 organic semiconductor layer 1 made of the organic semiconductor material of the present invention is formed between the electrodes. In addition, the configuration as shown in FIGS.

  FIG. 2 is a diagram showing an example of a schematic equivalent circuit diagram of an organic TFT sheet.

  The organic TFT sheet 10 has a large number of organic TFTs 11 arranged in a matrix. 7 is a gate bus line of each TFT 11, and 8 is a source bus line of each TFT 11. An output element 12 is connected to the source electrode of each TFT 11, and this output 12 is, for example, a liquid crystal, an electrophoretic element or the like, and constitutes a pixel in the display device. The pixel electrode may be used as an input electrode of the photosensor. In the illustrated example, a liquid crystal as an output element is shown by an equivalent circuit composed of a resistor and a capacitor. 13 is a storage capacitor, 14 is a vertical drive circuit, and 15 is a horizontal drive circuit.

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

Example 1
From compound (1) (Aldrich, Mw = 52500, Mn = 17400, Mw / Mn = 3.02), preparative GPC (Nippon Analytical Industrial Co., Ltd., LC-9101 type, column: JAIGEL-2.5H + JAIGEL-3H) Was used to remove low molecular weight components to obtain compound (1-1) and compound (1-2).

  Similarly, compound (11-1) and compound (11-2) are obtained from compound (11) (compound described in JP-A-2003-292588, Mw = 42500, Mn = 9200, Mw / Mn = 4.62). Compound (13-1) and Compound (13-2) were obtained from Compound (13) (a compound described in JP-T-2001-520289, Mw = 56000, Mn = 14100, Mw / Mn = 3.96).

  As a method for measuring the molecular weight of the above-mentioned polymer, Tosoh HLC8220 (column: TSKgel SuperHM-M, column temperature: 40 ° C., eluent: THF, flow rate 0.6 ml, data amount: 2 mg / 2 ml, detection device: RI) is used. I went.

Example 2
<< Production of Organic Thin Film Transistor 1 >>
A silicon oxide having a resistivity of 0.01 Ω · cm as a gate electrode was formed with a thermal oxide film having a thickness of 2000 mm to form a gate insulating layer, and then surface treatment with octadecyltrichlorosilane was performed. A chloroform solution of Compound 1 was applied using an applicator, and air-dried to form a cast film (thickness 50 nm), followed by heat treatment 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. An organic thin film transistor element 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.

<< Production of Organic Thin Film Transistors 2-9 >>
Organic thin film transistor elements 2 to 9 were produced in the same manner as in the production of the organic thin film transistor 1, except that the compound 1 was changed to the compounds shown in Table 1.

  The organic thin film transistor elements 1 to 9 produced as described above showed good operating characteristics of a p-channel enhancement type FET.

<< Evaluation of carrier mobility and ON / OFF ratio >>
For each of the obtained organic TFT elements 1 to 9, the carrier mobility and the ON / OFF ratio of each element immediately after fabrication and after standing for 1 month in the air were determined. In the present invention, the carrier mobility is obtained from the saturation region of the IV characteristic, and the ON / OFF ratio is obtained from the ratio of the drain current values when the drain bias is −50 V and the gate bias is −50 V and 0 V. It was.

  The obtained results are shown in Table 1.

  From Table 1, it was found that the organic thin film transistor element of the present invention had good characteristics as a transistor and further suppressed deterioration with time.

It is a figure which shows the structural example of the organic TFT which concerns on this invention. It is an example of the schematic equivalent circuit schematic of the organic TFT of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic-semiconductor layer 2 Source electrode 3 Drain electrode 4 Gate electrode 5 Insulating layer 6 Support body 7 Gate bus line 8 Source bus line 10 Organic TFT sheet 11 Organic TFT
12 Output element 13 Storage capacitor 14 Vertical drive circuit 15 Horizontal drive circuit

Claims (8)

A high molecular weight Mw in the range of 5,000 to 10,000,000 and a π-conjugated structure having a ratio Mw / Mn of Mw to number average molecular weight Mn of 3 or less as a partial structure An organic thin film transistor material containing a molecule. A high molecular weight Mw in the range of 5,000 to 10,000,000 and a π-conjugated structure having a ratio Mw / Mn of Mw to number average molecular weight Mn of 2 or less as a partial structure An organic thin film transistor material containing a molecule. As a partial structure, a π-conjugated structure having a weight average molecular weight Mw in the range of 5,000 to 10,000,000 and a ratio Mw / Mn of Mw to number average molecular weight Mn of 1.5 or less. An organic thin film transistor material comprising a polymer having the same. The organic thin film transistor material according to any one of claims 1 to 3, wherein the polymer having the π-conjugated structure as a partial structure includes an aromatic heterocyclic ring as the partial structure. The organic thin film transistor material according to claim 4, wherein the aromatic heterocycle is a 5-membered ring or a 6-membered ring. An organic thin film transistor, wherein the organic thin film transistor material according to claim 1 is used for a channel layer. An organic charge transporting material and a gate electrode directly or indirectly in contact with the organic charge transporting material, and by applying a charge between the gate electrode and the organic charge transporting material, the organic charge transporting property In a field effect transistor that controls the current in a material,
A field effect transistor, wherein the organic charge transporting material is the organic thin film transistor material according to any one of claims 1 to 5. A switching element comprising the organic thin film transistor according to claim 6 or the field effect transistor according to claim 7.

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