JP2007088115A - Organic semiconductor material, organic semiconductor film, organic semiconductor device, and organic thin-film transistor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form an organic semiconductor film by applying an organic semiconductor material whose solvent solubility is improved, and to provide an organic semiconductor device, an organic thin-film transistor, and an organic EL element having the device or the transistor, having high carrier mobility by using the obtained organic semiconductor film. <P>SOLUTION: The organic semiconductor material contains a compound having a partial structure expressed by an expression 1. In the expression 1, R<SB>1</SB>indicates a substituent, and R<SB>2</SB>-R<SB>6</SB>indicate a hydrogen atom or a substituent. However, at least one of R<SB>3</SB>-R<SB>6</SB>is an alkenyl group, an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. No rings are formed by R<SB>3</SB>and R<SB>4</SB>' and R<SB>5</SB>and R<SB>6</SB>each; and n1+n2 indicates an integer of 0-2 or smaller. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic semiconductor material, an organic semiconductor film, an organic semiconductor device, and an organic thin film transistor.

  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 in paper media has been increasingly digitized. As a mobile display medium that is thin, light, and portable, electronic paper or digital paper can be used. The need for is increasing.

  In general, in a flat panel display device, a display medium is formed using elements utilizing liquid crystal, organic EL (organic electroluminescence), 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. Yes. As for the semiconductor portion that is the key to the switching operation, a plurality of types of semiconductor layers such as p-type and n-type are stacked. 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. In addition to charge transport materials for organic EL devices, these compounds can be used for organic laser oscillation devices (for example, see Non-Patent Document 1) and organic thin film transistor devices (organic TFT devices) reported in many papers. Is expected (see, for example, Non-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 such as acenes such as pentacene and tetracene (see, for example, Patent Document 1), phthalocyanines including lead phthalocyanine, perylene and its tetra. Low molecular weight compounds such as carboxylic acid derivatives (see, for example, 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 5-membered aromatic heterocycles are condensed symmetrically on anthracene (for example, see Patent Document 4), mono-, oligo- and polydithienopyridines (for example, see Patent Document 5), polythiophene, polythienylene vinylene Conjugated high such as poly-p-phenylene vinylene A material that exhibits a sufficient carrier mobility / ON / OFF ratio while maintaining sufficient solubility in a solvent is not limited to a limited number of compounds (eg, non-patent documents 1 to 3). Not found.

  Recently, a very high mobility has been reported by a single crystal of rubrene, which is a highly soluble acene (see, for example, Non-Patent Document 4), but a rubrene film formed by solution casting is like this. A single crystal structure is not taken and sufficient mobility is not obtained.

  Further, pentacene, which has been reported to exhibit high carrier mobility and excellent semiconductor device characteristics, has a problem that it is insoluble or hardly soluble in organic solvents. In order to improve this point, a compound having a functional group added to pentacene is also disclosed, and it has been reported that relatively good carrier mobility can be obtained by solution coating (for example, see Patent Document 6). .

  However, these acene-based compounds such as rubrene and pentacene are easily oxidized by air and are converted into oxidants and dimers such as endoperoxide, and the performance as a field effect transistor is greatly deteriorated. It is known that there are still problems to be solved regarding the storage stability in solution and the stability of the coating film.

  As an example of an acene compound that is relatively stable against oxidation, there is a report that some compounds in which the 6th and 13th positions of pentacene are substituted with silylethynyl groups have good coating film stability (for example, (See Non-Patent Documents 5 and 6 and Patent Document 7.)

  However, these reports only describe the qualitative properties that the stability against oxidation has been improved, and the stability to the extent that it can withstand practical use has not yet been obtained.

Therefore, a novel charge transporting material that dissolves in a high concentration in a solvent having process suitability, has sufficient carrier mobility, on / off ratio, and stability in a solution state is used. Development of a semiconducting composition that has been long-awaited is highly desired.
JP-A-5-55568 Japanese Patent Laid-Open No. 5-190877 JP-A-8-264805 JP-A-11-195790 JP 2003-155289 A International Publication No. 03/016599 Pamphlet US Pat. No. 6690029 Specification “Science” 289, 599 (2000) “Nature” 403, 521 (2000) Advanced Material, 2002, No. 2, page 99 Science, 2004, 303, 5664, 1644-1646. Org. Lett. , Vol. 4 (2002), 15 pages J. et al. Am. Chem. Soc. , Vol. 127 (2005), 4986 pages

  An object of the present invention is to provide an organic semiconductor material having improved oxidation stability, stability over time, and solvent solubility, and an organic semiconductor film can be formed by applying the organic semiconductor material. An object of the present invention is to provide an organic semiconductor device, an organic thin film transistor, and an organic EL element including the device or the transistor having high carrier mobility by using a film.

  The above object of the present invention has been achieved by the following constitutions (1) to (12).

(1)
An organic semiconductor material comprising a compound having a partial structure represented by the following general formula (1).

[Wherein, R ₁ represents a substituent, and R _{2 to} R ₆ represent a hydrogen atom or a substituent. Provided that at least one of R _{3 to} R ₆ represents an alkenyl group, an alkynyl group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group, and R ₃ and R ₄ , and R ₅ and R ₆ , Each does not form a ring. n1 + n2 represents an integer of 0 to 2 or less. ]
(2)
The organic semiconductor material as described in (1) above, wherein R _{2 in the} general formula (1) is a group represented by the following general formula (a).

[Wherein R ₁ 'represents a substituent. ]
(3)
In the above (1) or (2), R _3, R ₄ , R ₅ or R _{6 in the} general formula (1) is an aromatic hydrocarbon ring group or an aromatic heterocyclic group, respectively. Organic semiconductor materials.

(4)
R ₁ and R ₁ ′ in the general formula (1) are each a branched alkyl group, cycloalkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, aromatic heterocyclic group, or Si (R) ₃ group. (R represents a substituent.) The organic semiconductor material according to (2) or (3), which is represented by

(5)
In the general formula (1), R ₁ and R ₁ ′ are groups represented by Si (R) ₃ groups (R represents a substituent), respectively (2) or (3 ) Organic semiconductor material.

(6)
An organic semiconductor material comprising a compound having a partial structure represented by the following general formula (2).

[Wherein, R ₁ and R ₁ ′ represent a substituent, and R _{7 to} R ₁₀ each represents a hydrogen atom or a substituent, and may be bonded to each other to form a ring. n1 + n2 represents an integer of 0-2. ]
(7)
R ₁ and R ₁ ′ in the general formula (2) are each a branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or a Si (R) ₃ group. (R represents a substituent.) The organic semiconductor material according to (6), which is represented by

(8)
R ₁ and R ₁ ′ in the general formula (2) are each a group represented by Si (R) ₃ (R represents a substituent), and the organic according to (6) Semiconductor material.

(9)
An organic semiconductor film comprising the organic semiconductor material according to any one of (1) to (8).

(10)
An organic semiconductor film formed by dissolving the organic semiconductor material according to any one of (1) to (8) in an organic solvent, and applying and drying the obtained solution.

(11)
The organic-semiconductor device characterized by using the organic-semiconductor material of any one of said (1)-(8).

(12)
An organic thin film transistor using the organic semiconductor material according to any one of (1) to (8) in a semiconductor layer.

  According to the present invention, an organic semiconductor material having improved oxidation stability, stability over time, and solvent solubility is provided, and an organic semiconductor film can be formed by applying the organic semiconductor material. It was possible to provide an organic semiconductor device having high carrier mobility, an organic thin film transistor, and an organic EL element including the device or the transistor.

  In the organic semiconductor material of the present invention, an organic semiconductor film useful for thin film transistor applications can be obtained by using the configuration defined in any one of claims 1 to 8. In addition, it was found that an organic thin film transistor (also referred to as an organic TFT) manufactured using the organic semiconductor film has excellent transistor characteristics such as high carrier mobility and good ON / OFF characteristics. Moreover, it turned out that the organic electroluminescent element provided with organic TFT shows a favorable light emission characteristic.

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

《Organic semiconductor material》
The organic semiconductor material of the present invention will be described.

  As a conventionally known organic semiconductor material, a compound in which two or more aromatic rings are linearly condensed, such as acenes represented by pentacene, is well known as a high mobility material.

  However, conventionally known acenes and the like tend to be easily oxidized and converted to a dimer as the number of rings increases, and aromatic rings with many condensed rings have a strong intermolecular cohesive force. There was a problem that it was difficult to apply to a process using a solution because of low solubility.

  As a result of repeated investigations by the researchers of the present invention on the above problems, a compound having higher stability against oxidation can be obtained by using acene having a ring number of 3 or less as a skeleton among conventionally known acenes. I found.

  Furthermore, by substituting an electronically attractive ethynyl group into an acene derivative skeleton having 3 or less rings, oxidation stability is further improved. In addition to the ethynyl group, an alkenyl group, alkynyl group, aromatic Π conjugate plane with an expanded π electron cloud by having an aromatic hydrocarbon group (also referred to as aromatic carbocyclic group, aryl group, etc.) or aromatic heterocyclic group (also referred to as heteroaryl group) as a substituent. And a compound which is stable against oxidation was obtained.

  In addition, by introducing a group such as a thiophene ring that maintains the planarity of the molecule, the π stack between molecules was further promoted, and a film in which molecules were closely arranged could be obtained.

  In addition, molecules having high planarity such as pentacene and sexualthiophene, which are examples of conventionally known acenes, are often insoluble, but are represented by the above general formula (1) relating to the organic semiconductor material of the present invention. The compound having the partial structure and the compound having the partial structure represented by the general formula (2) greatly improve the solubility in the solvent by introducing a substituted ethynyl group into the peri-position of the acene skeleton. I was able to.

  Furthermore, by introducing a silyl group as a substituent of the ethynyl group, it has become possible to adopt a “Face-to-face” structure instead of a herringbone structure typified by pentacene.

  From the above, it has become possible to provide a material with high oxidation stability and high mobility.

  Here, the aromatic ring in the present invention refers to an aromatic hydrocarbon ring and an aromatic heterocyclic ring unless otherwise specified. The aromatic hydrocarbon ring and aromatic heterocyclic ring will be described in detail later.

<< Compound having a partial structure represented by the general formula (1) >>
The compound having a partial structure represented by the general formula (1) according to the present invention will be described.

  The organic semiconductor material of the present invention is characterized by having a partial structure represented by the general formula (1), and includes at least a compound having a partial structure represented by the general formula (1) as a main component. It is a feature. Here, the main component means that 50% by mass or more of the total mass of the organic semiconductor material is contained. Of course, the compound which has the partial structure represented by General formula (1) may be contained by content of 100 mass% in the organic-semiconductor material of this invention.

In the general formula (1), examples of the substituent represented by R _{1 to} R ₆ include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, and a tert-pentyl group). Group, hexyl group, octyl group, tert-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, for example) Allyl group, 1-propenyl group, 2-butenyl group, 1,3-butadienyl group, 2-pentenyl group, isopropenyl group, etc.), alkynyl group (for example, ethynyl group, propargyl group, etc.), aromatic hydrocarbon group (Also called aromatic carbocyclic group, aryl group, etc., for example, phenyl group, p-chlorophenyl group, mesityl , Tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (also called heteroaryl group, for example, Pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazole- 1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl Group, carbazolyl group, cal Borinyl group, diazacarbazolyl group (indicating that one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom), quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc. , Heterocyclic groups (for example, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy groups (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group) Group), cycloalkoxy group (eg cyclopentyloxy group, cyclohexyloxy group etc.), aryloxy group (eg phenoxy group, naphthyloxy group etc.), alkylthio group (eg methylthio group, ethylthio group, propylthio group, pentylthio). Group, Xylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, etc.) , Ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group) Methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group 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, octyl) Carbonyl 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, ethylcarbonylamino group, dimethylcarbonylamino group) 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, dodecylaminocarbonyl group, phenylamino Carbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethyl) Ureido 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, cyclohexyl) Sulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group (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, 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, pentafluoroethyl group, pentafluorophenyl group) Etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.).

  These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

Among them, in the general formula (1), the substituent represented by R ₂ is preferably a group represented by the general formula (a). Here, in the general formula (a), R ₁ ′ The substituent represented is synonymous with the substituent represented by R < ₁ > -R < ₆ > in the said General formula (1).

Further, in the general formula (1), R ₁ and R ₁ ′ are each a branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or Si (R It is preferably represented by ₃ groups (R represents a substituent).

In the general formula (1), examples of the branched alkyl groups represented by R ₁ and R ₁ ′ include the alkyl groups of the substituents represented by R _{1 to} R ₆ in the general formula (1). Examples thereof include isopropyl group, tert-butyl group, tert-pentyl group, tert-octyl group and the like.

In the general formula (1), the cycloalkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, and aromatic heterocyclic group represented by R ₁ and R ₁ ′ It is synonymous with a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, and an aromatic heterocyclic group, which are described as substituents represented by R _{1 to} R ₆ , respectively.

In the general formula (1), the substituents represented by R of the Si (R) ₃ group represented by R ₁ and R ₁ ′ are represented by R _{1 to} R ₆ in the general formula (1), respectively. It is synonymous with the substituent made.

In the general formula (1), it is preferable that R ₃ or R ₄ , R ₅ or R ₆ is the aromatic hydrocarbon ring group or the aromatic heterocyclic group, respectively. The hydrocarbon group and the aromatic heterocyclic group are each described as a substituent represented by R _{1 to} R ₆ in the general formula (1), respectively. Each group has the same meaning.

<< Compound having a partial structure represented by the general formula (2) >>
The compound having a partial structure represented by the general formula (1) according to the present invention is preferably a compound having a partial structure represented by the general formula (2) according to the present invention.

In the general formula _{(2), R 1, R} 1 ' substituent represented by each of the in the above general formula _{(1), R 1, R} 1' is synonymous with the substituent represented by each of.

In the general formula (2), the substituents represented by R _{7 to} R ₁₀ have the same meanings as the substituents represented by R _{1 to} R ₆ in the general formula (1).

  Hereinafter, although the specific example of the compound which has the partial structure represented by General formula (1) or (2) based on this invention is shown, this invention is not limited to these.

<Synthesis example>
The compound having a partial structure represented by the general formula (1) or (2) according to the present invention can be synthesized by referring to a conventionally known synthesis method of a heterocyclic compound. Examples of the synthesis of the exemplified compound 13 given as specific examples are shown as an example, but the present invention is not limited thereto.

  << Synthesis of Exemplified Compound 13 >>

  The outline of the synthesis scheme of the above compound is shown below.

  First, J.H. Am. Chem. Soc. , Vol. 127 (2005), pages 4986-4987, and intermediate 2 was synthesized. Furthermore, Intermediate 3 was synthesized by Suzuki Coupling from Intermediate 2 and 2-thienyl-5-thiopheneboronic acid. After intermediate 3 was brominated with NBS to give intermediate 4, exemplary compound 13 was synthesized by Suzuki Coupling with phenylboronic acid.

<Organic semiconductor film>
The organic semiconductor film according to the present invention will be described.

  The organic semiconductor material of the present invention can be mixed with an appropriate organic solvent (described later) and used as a solution or dispersion.

  When producing an organic semiconductor film using a solution containing the organic semiconductor material of the present invention, any organic solvent may be used, or two or more organic solvents may be mixed and used. Preferably, it contains at least one non-halogen solvent, and more preferably only non-halogen solvent.

<< Solution or dispersion at room temperature >>
The organic semiconductor film of the present invention is preferably produced through a step of forming a film using a solution or a dispersion at room temperature, prepared by mixing the organic semiconductor material of the present invention with the organic solvent shown below. Here, the solution or dispersion at room temperature preferably forms a solution or dispersion when the organic semiconductor material and the organic solvent are mixed under conditions of 10 ° C. to 80 ° C. Although the organic semiconductor material represents a state where the organic semiconductor material is dispersed in the form of particles, a state where the organic semiconductor material is partially dissolved in the dispersion is also included.

  Further, as one embodiment of the dispersion, for example, it dissolves under a temperature condition of 80 ° C. to form a solution, but when returned to room temperature (usually showing a temperature of about 25 ° C.), particles or aggregates of organic semiconductor material And a state in which precipitates are dispersed in an organic solvent.

(Organic solvent)
There is no restriction | limiting in particular as an organic solvent used for preparation of said solution or dispersion liquid, Although a single solvent or a mixed solvent may be sufficient, Preferably, a non-halogen-type solvent is used. Non-halogen solvents used in the present invention include aliphatic solvents such as hexane and octane, alicyclic solvents such as cyclohexane, aromatic solvents such as benzene, toluene and xylene, tetrahydrofuran, dioxane, and ethylene glycol diethyl ether. , Ether solvents such as anisole, benzyl ethyl ether, ethyl phenyl ether, diphenyl ether, and methyl-t-butyl ether, ester solvents such as methyl acetate, ethyl acetate, and ethyl cellosolve, alcohol solvents such as methanol, ethanol, and isopropanol, acetone , Ketone solvents such as methyl ethyl ketone, cyclohexanone, 2-hexanone, 2-heptanone and 3-heptanone, other dimethylformamide, dimethylsulfoxide, diethylformamide, 1,3- Oxolane, and the like.

  Further, the organic solvent used in combination is not particularly limited, but preferred examples include methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, pyrrolidone, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, Examples include methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, butyl lactate, methyl β-methoxypropionate, ethyl β-ethoxypropionate, propylene glycol monomethyl ether acetate, toluene, xylene, hexane, limonene, cyclohexane, etc. It is done. Two or more of these organic solvents can be used in combination.

  Further, as the ester solvent, oxyisobutyric acid alkyl ester or the like may be used, and as oxyisobutyric acid ester, α-methoxyisobutyrate methyl, α-methoxyisobutyrate ethyl, α-ethoxyisobutyrate methyl, α-ethoxyisobutyrate ethyl, etc. α-alkoxyisobutyric acid alkyl esters; β-alkoxyisobutyric acid alkyl esters such as methyl β-methoxyisobutyrate, ethyl β-methoxyisobutyrate, methyl β-ethoxyisobutyrate, ethyl β-ethoxyisobutyrate; and methyl α-hydroxyisobutyrate, α Α-hydroxyisobutyric acid alkyl esters such as ethyl-hydroxyisobutyrate, and in particular, methyl α-methoxyisobutyrate, methyl β-methoxyisobutyrate, methyl β-ethoxyisobutyrate or methyl α-hydroxyisobutyrate may be used. it can.

<< Organic semiconductor device, organic thin film transistor (also called organic TFT) >>
The organic semiconductor device and organic thin film transistor (also referred to as organic TFT in the present application) of the present invention will be described.

  The organic semiconductor material of the present invention can be used for a semiconductor layer such as an organic semiconductor film, an organic semiconductor device, and an organic thin film transistor (organic TFT), thereby providing an organic semiconductor device and an organic TFT that are driven well.

  An organic TFT (organic thin film transistor) has a source electrode and a drain electrode connected by an organic semiconductor channel as a semiconductor layer on a support, and a top gate type having a gate electrode via a gate insulating layer thereon, A bottom gate type having a gate electrode on a support and having a source electrode and a drain electrode connected by an organic semiconductor channel through a gate insulating layer is roughly classified.

  In order to install the organic semiconductor material of the present invention on the semiconductor layer of the organic TFT, 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. It is preferable to install on the substrate by coating, spin coating, printing, ink jet method, ablation method or the like.

  In this case, the solvent for dissolving the organic semiconductor compound according to the present invention is not particularly limited as long as the organic semiconductor compound can be dissolved to prepare a solution with an appropriate concentration. Chain ether solvents such as diisopropyl 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 And aromatic solvents such as nitrobenzene and m-cresol, N-methylpyrrolidone, carbon disulfide and the like. Of these solvents, a solvent containing a non-halogen solvent is preferable, and a non-halogen solvent is preferable.

  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, 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, 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 organic thin-film transistor (organic TFT) using the organic thin film formed using the organic-semiconductor compound concerning 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 thin film transistor material of the present invention is formed between the two electrodes, and on that, 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 thin film transistor 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 the output element 12 is, for example, a liquid crystal or an electrophoretic element, 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.

  Moreover, the organic TFT using the organic semiconductor material of the present invention can be applied to the technology introduced in, for example, SID2005, sessions 49-1, 2 and 3, and an a-Si transistor is used as the organic semiconductor transistor of the present invention. By replacing it, it is possible to obtain good characteristics.

  Hereinafter, as an example of the technology application, an organic electroluminescence element (organic EL element) including the organic TFT of the present invention will be described.

<< Organic EL element (Organic electroluminescence element) >>
The organic semiconductor device or the organic thin film transistor of the present invention can be provided in an organic electroluminescence element (also referred to as an organic EL element). The organic EL element of the present invention has, for example, an organic EL layer (between an anode and a cathode) The organic compound layer) may be sandwiched between them, and these structures can be prepared using a conventionally known layer structure, a material of an organic EL layer, or the like. For example, the literature etc. of Nature, 395 volumes, 151-154 pages can be referred.

  In light emitting the organic EL element of the present invention (for example, applied to a display device, a lighting device, etc.), the organic semiconductor device of the present invention is obtained from the viewpoint of obtaining high light emission luminance and a long light emission lifetime. Or it is preferable to have the organic thin-film transistor of this invention.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these. Here, structural formulas of comparative organic semiconductor materials (also referred to as organic semiconductor compounds) used in the examples are shown below.

Example 1
<< Production of Organic Thin Film Transistor 1 >>
A Si oxide having a specific resistance 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 comparative compound (1) (poly (3-hexylthiophene) (regioregular, manufactured by Aldrich, average molecular weight 89000, PHT)) was bubbled in a nitrogen atmosphere for 30 minutes on the Si wafer subjected to such surface treatment. The cast film was formed by dissolving at a concentration of 0.5% by mass with respect to toluene, spin-coating under a nitrogen atmosphere (rotation speed 2500 rpm, 15 seconds), and air-drying to form a cast film 50 under a nitrogen atmosphere. A heat treatment was carried out at 30 ° C. for 30 minutes.

  Furthermore, gold was deposited on the surface of this film using a mask to form source and drain electrodes. An organic thin film transistor 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 Transistor 2 >>
An organic thin film transistor 2 was produced in the same manner as in the production of the organic thin film transistor 1, except that the comparative compound (1) was changed to the comparative compound (2) (pentacene, a commercially available reagent manufactured by Aldrich was used after sublimation purification).

<< Production of Organic Thin Film Transistor 3 >>
Comparative compound 3 was synthesized by the method described in 1.

  An organic thin film transistor 3 was produced in the same manner as in the production of the organic thin film transistor 1, except that the comparative compound 2 was changed to the comparative compound 3.

<< Production of Organic Thin Film Transistor 4 >>
In the production of the organic thin film transistor 1, the organic thin film transistor 4 was produced in the same manner except that the comparative compound 2 was changed to the comparative compound 4 (Lubrene, manufactured by Aldrich, and used by sublimation and refinement of a commercially available reagent).

<< Production of Organic Thin Film Transistor 5 >>
Comparative compound 5 is described in J. Org. Am. Chem. Soc. , Vol. 123 (2001), p9486, supporting information.
An organic thin film transistor 5 was produced in the same manner as in the production of the organic thin film transistor 1, except that the comparative compound 2 was changed to the comparative compound 5.

<< Production of Organic Thin Film Transistor 6-10 >>
In the production of the organic thin film transistor 2, organic thin film transistors 6 to 10 were produced in the same manner except that the organic semiconductor material of the present invention described in Table 1 was used instead of the comparative compound 1.

<< Evaluation of carrier mobility and ON / OFF value >>
About the obtained organic thin-film transistors 1-10, the carrier mobility and ON / OFF value of each element were measured immediately after element preparation. 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.

  In addition, the same evaluation was carried out for 48 hours after putting each element in an environmental chamber at 40 ° C. and 90% RH, and then the carrier mobility / ON / OFF ratio was measured again.

From Table 1, the organic thin film transistors 5 to 10 produced using the organic semiconductor material of the present invention show excellent characteristics in both carrier mobility and ON / OFF ratio immediately after production, and also after the durability test. Is 10 ^-2 or more, and the ON / OFF ratio is 10 ⁵ or more.

Example 2
<< Production of organic EL element >>
The organic EL element was produced by referring to the method described in Nature, Vol. 395, pages 151 to 154, and producing a top emission type organic EL element having a sealing structure as shown in FIG. 3, 101 is a substrate, 102a is an anode, 102b is an organic EL layer (specifically, an electron transport layer, a light emitting layer, a hole transport layer, etc. are included), 102c is a cathode, and an anode 102a The light emitting element 102 is formed by the organic EL layer 102b and the cathode 102c. Reference numeral 103 denotes a sealing film. The organic EL element of the present invention may be either a bottom emission type or a top emission type.

  The organic EL element of the present invention and the organic thin film transistor of the present invention (herein, the organic thin film transistor of the present invention is used as a switching transistor, a driving transistor, etc.) were produced to produce an active matrix light emitting element. For example, as shown in FIG. 4, a mode in which a substrate in which a TFT 602 (or an organic thin film transistor 602 may be formed) is formed on a glass substrate 601 is used as an example. Here, a known TFT manufacturing method can be referred to for the TFT 602 manufacturing method. Of course, the TFT may be a conventionally known top gate TFT or bottom gate TFT.

  The organic EL device produced above showed good light emission characteristics in various light emission forms such as single color, full color, and white.

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. It is a schematic diagram which shows an example of the organic EL element which has a sealing structure. It is a schematic diagram which shows an example of the board | substrate which has TFT used for an organic EL element.

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
DESCRIPTION OF SYMBOLS 12 Output element 13 Storage capacitor 14 Vertical drive circuit 15 Horizontal drive circuit 101, 201 Substrate 102 Organic EL element 102a, 202 Anode 102b Organic EL layer 102c, 204 Cathode 103 Sealing film 205 Drive element 206 Hole transport layer 207 Light emitting layer 208 Electron transport layer 601 Substrate 602 TFT

Claims (12)

An organic semiconductor material comprising a compound having a partial structure represented by the following general formula (1).

[Wherein, R ₁ represents a substituent, and R _{2 to} R ₆ represent a hydrogen atom or a substituent. Provided that at least one of R _{3 to} R ₆ represents an alkenyl group, an alkynyl group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group, and R ₃ and R ₄ , and R ₅ and R ₆ , Each does not form a ring. n1 + n2 represents an integer of 0 to 2 or less. ] The organic semiconductor material according to claim 1, wherein R _{2 in the} general formula (1) is a group represented by the following general formula (a).

[Wherein R ₁ 'represents a substituent. ] _3. The organic semiconductor according to claim 1, wherein R _3, R ₄ , R _5, or R _{6 in the} general formula (1) is an aromatic hydrocarbon ring group or an aromatic heterocyclic group, respectively. material. R ₁ and R ₁ ′ in the general formula (1) are each a branched alkyl group, cycloalkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, aromatic heterocyclic group, or Si (R) ₃ group. The organic semiconductor material according to claim 2, wherein R represents a substituent. The R ₁ and R ₁ ′ in the general formula (1) are groups each represented by a Si (R) ₃ group (R represents a substituent). Organic semiconductor materials. An organic semiconductor material comprising a compound having a partial structure represented by the following general formula (2).

[Wherein, R ₁ and R ₁ ′ represent a substituent, and R _{7 to} R ₁₀ each represents a hydrogen atom or a substituent, and may be bonded to each other to form a ring. n1 + n2 represents an integer of 0-2. ] R ₁ and R ₁ ′ in the general formula (2) are each a branched alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or a Si (R) ₃ group. The organic semiconductor material according to claim 6, wherein R represents a substituent. The organic semiconductor according to claim 6, wherein R ₁ and R ₁ ′ in the general formula (2) are groups each represented by Si (R) ₃ (R represents a substituent). material. An organic semiconductor film comprising the organic semiconductor material according to claim 1. An organic semiconductor film formed by dissolving the organic semiconductor material according to any one of claims 1 to 8 in an organic solvent, and applying and drying the obtained solution. The organic-semiconductor device using the organic-semiconductor material of any one of Claims 1-8. An organic thin film transistor, wherein the organic semiconductor material according to claim 1 is used for a semiconductor layer.

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