JP7156769B2 - Organic semiconductor composition, organic thin film and organic thin film transistor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an organic semiconductor composition, an organic thin film obtained using the organic semiconductor composition, and an organic thin film transistor having the organic thin film.

In general, field-effect transistors, which have a structure in which a semiconductor on a substrate is provided with a source electrode, a drain electrode, and a gate electrode, etc. via these electrodes and an insulating layer, currently use inorganic semiconductors such as silicon. Materials are mainly used. In particular, a thin film transistor, in which a layer of amorphous silicon is provided on a substrate such as glass, is widely used as a switching element in addition to being used in integrated circuits as a logic circuit element in the field of displays and the like. Recently, studies on using an oxide semiconductor as a semiconductor material have been actively conducted. However, when such an inorganic semiconductor material is used, high-temperature processing is required during the production of the field effect transistor, so films, plastics, and the like, which are inferior in heat resistance, cannot be used for the substrate. Furthermore, the production equipment is expensive and a large amount of energy is required during the production, so that the resulting field effect transistor is expensive and its application range is very limited.

On the other hand, field effect transistors using organic semiconductor materials that do not require high-temperature treatment during the production of field effect transistors are being developed. If an organic semiconductor material can be used, it will be possible to manufacture in a low-temperature process, and the range of usable substrate materials will be expanded. As a result, it becomes possible to fabricate thin film transistors (organic thin film transistors) that are more flexible, lighter, and less fragile than when inorganic semiconductors such as amorphous silicon are used. In addition, since application of a solution containing an organic semiconductor material, printing by inkjet or the like, or the like can be applied to the manufacturing method, there is a possibility that a large-area field effect transistor can be manufactured at low cost.

However, many of the organic compounds that have been conventionally used as organic semiconductor materials are poorly soluble in organic solvents. It has been common practice to form an organic thin film thereon.
In recent years, by improving the solubility of an organic compound in an organic solvent, it has become possible to obtain an organic thin film transistor exhibiting relatively high carrier mobility by a coating method. However, in order to put devices made of organic semiconductor materials into practical use, it is necessary to have small variations in mobility when they are mass-produced. there is

Non-Patent Document 1 discloses a method for producing an organic thin film by a drop casting method using an organic semiconductor solution in which TIPS-pentacene and polystyrene are mixed. It is described that the mobility is superior to that of an organic semiconductor device having an organic thin film obtained by using an organic semiconductor solution of only pentacene, and the mobility variation is improved. However, the variation in the mobility of the organic semiconductor device obtained by the method of Non-Patent Document 1 is σ=40% with respect to the average mobility, which has not yet reached a sufficient level.

In Non-Patent Document 2, Poly[2,5-bis(alkyl)pyrrolo[3,4-c]pyrrole-1,4(2H ,5H)-dione-alt-5,5-di(thiophen-2-yl)22,20-(E)-2-(2-(thiophen-2-yl)vinyl)-thiophene] and polystyrene were dissolved. A method for forming an organic thin film by an inkjet method using an organic semiconductor solution is disclosed, and an organic semiconductor device having the organic thin film has excellent mobility and improved mobility variation. Have been described. However, Non-Patent Document 2 uses a halogen solvent, which poses a safety problem.

Non-Patent Document 3 discloses a method for producing an organic thin film using an organic semiconductor solution in which poly(3-hexylthiophene-2,5-diyl) and PMMA are mixed, and an organic semiconductor device having the organic thin film. describes that leakage current and on/off ratio are improved. However, Non-Patent Document 3 does not discuss the mobility and its variation.

Patent Document 1 describes an organic electronic device having an organic semiconductor thin film formed by flexographic printing using a formulation containing an organic semiconductor compound, a polymer binder, and at least one organic solvent and having a viscosity of 15 mPas at 25°C ( Organic thin film transistors) have been described to exhibit high mobilities of about 2 cm ² /Vs. However, Patent Literature 1 does not describe any variation in mobility.

Patent Document 2 discloses an organic semiconductor compound and at least one organic solvent having a Hansen solubility parameter value within a specific range, a viscosity of less than 15 mPas, and a surface tension within the range of 22 to 50 mN/m. Organic electronic devices (organic thin film transistors) with organic semiconductor films formed by flexographic printing using the formulations are described to exhibit high mobilities up to 2.5 cm ² /Vs. However, Patent Document 2 does not describe any variation in mobility.

Patent Document 3 discloses a specific organic semiconductor compound, a binder polymer, a solvent having a naphthalene structure, and an organic semiconductor containing a solvent having an SP value smaller than that of the solvent having the naphthalene structure by 2.0 MPa ^1/2 or more and a low boiling point. An organic semiconductor element (organic thin film transistor element) having an organic semiconductor thin film formed by an ink jet method or a flexographic printing method using the composition showed no deterioration in characteristics even after heating at 120 ° C. for 1 hour, and exhibited excellent heat resistance. It is stated to have shown stability. However, Patent Document 3 does not describe any variation in mobility.

In Patent Document 4, an organic semiconductor device having an organic thin film formed using an organic semiconductor composition containing an organic semiconductor compound, a liquid crystalline compound, and an insulating polymer compound has a high mobility of 1 to 2 cm ² /Vs. It is described that the However, Patent Literature 4 does not describe anything about variations in mobility.

In Patent Document 5, an organic semiconductor solution containing an organic semiconductor compound, a polymer component, solvents A and B that are good solvents for the organic semiconductor, and solvent C that is a poor solvent for the organic semiconductor is used to form an organic semiconductor by an inkjet method. Electroluminescent devices with thin films are said to exhibit high brightness. However, Patent Document 5 does not describe the characteristics of an organic thin film transistor having the organic thin film.

Patent Document 6 discloses that an electroluminescence device having an organic thin film formed using a polymer organic semiconductor material and an organic semiconductor solution comprising a good solvent A and a poor solvent B for the organic semiconductor material exhibited high luminance. Have been described. However, Patent Document 6 does not describe the characteristics of an organic thin film transistor having the organic thin film.

US Pat. No. 5,300,001 discloses a semiconductor condensed thiophene polymer ink formulation comprising a polymeric organic semiconducting material, a first solvent that is a cycloaliphatic compound, and a second solvent that is an aromatic compound, obtained by spin-coating. An organic thin film transistor device having an organic semiconductor thin film is disclosed. However, the mobility of the organic thin film transistor element in the example of Patent Document 7 is 0.3 cm ² /Vs at maximum, which cannot be said to be high mobility.

Japanese translation of PCT publication No. 2016-534553 Japanese Patent Publication No. 2017-63218 WO2016/052254 WO2016/143774 Japanese Patent Publication No. 2007-527624 Japanese Patent Publication No. 2008-503870 Japanese Patent Application Publication No. 2015-532788

Synthetic. Met. 2016, 221, 186. Polymer Physics, 2016, 54, 1760. Appl. Mater. Interfaces. 2015, 7, 16486.

The present invention provides an organic semiconductor composition capable of producing an organic thin film by a solution method, an organic thin film obtained using the organic semiconductor composition, and an organic thin film having a high mobility while maintaining mobility variation. An object of the present invention is to provide a small practical organic thin film transistor.

As a result of intensive studies to solve the above problems, the present inventors have discovered an organic semiconductor compound, an insulating compound, an organic solvent A which is a good solvent for the organic semiconductor compound and the insulating compound, and the organic semiconductor compound and the insulating compound. The inventors have found that an organic semiconductor composition that contains an organic solvent B, which is a poor solvent for an insulating compound, and that satisfies specific conditions can solve the above problems, and have completed the present invention.

That is, the present invention provides (1) an electrode substrate having a substrate, an insulating compound layer made of an insulating compound provided on the substrate, and an electrode made of a metal thin film layer provided on the insulating compound layer; An organic semiconductor composition for forming an organic thin film of an organic thin film transistor element having an organic thin film layer containing an organic semiconductor compound provided on an electrode substrate,
Containing an organic semiconductor compound, an insulating compound, an organic solvent A that is a good solvent for the organic semiconductor compound and the insulating compound, and an organic solvent B that is a poor solvent for the organic semiconductor compound and the insulating compound,
In addition, the sliding angle of the organic solvent A solution having an insulating compound concentration of 1% by weight or more with respect to the insulating compound layer and the metal thin film layer is θ _{SUB (A')} (°) and θ _{METAL (A')} (°), and the insulating property When the sliding angle of the saturated organic solvent B solution of the compound with respect to the insulating compound layer and the metal thin film layer is θ _{SUB (B')} (°) and θ _{METAL (B')} (°), the following conditions (1) to (3)
Condition (1);
1°≦|θ _METAL(A′) −θ _SUB(A′) |
Condition (2):
1°≦|θ _METAL(B′) −θ _SUB(B′) |
Condition (3):
1°<||θ _METAL(A′) −θ _SUB(A′) |−|θ _METAL(B′) −θ _SUB(B′) ||
An organic semiconductor composition that satisfies all the relationships of
(2) Condition (3) is 1°<||θ _{METAL (A′)} −θ _{SUB (A′)} |−|θ _{METAL (B′)} −θ _{SUB (B′)} ||<35°
The organic semiconductor composition according to the preceding item (1),
(3) Condition (1) is 1°≦|θ _METAL(A′) −θ _SUB(A′) |≦20°
and condition (2) is 1°≦|θ _METAL(B′) −θ _SUB(B′) |≦40°
The organic semiconductor composition according to the preceding item (2),
(4) Condition (1) is 20°≦|θ _METAL(A′) −θ _SUB(A′) |≦40°
and condition (2) is 1°≦|θ _METAL(B′) −θ _SUB(B′) |≦40°
The organic semiconductor composition according to the preceding item (2),
(5) The organic semiconductor composition according to any one of the preceding items (1) to (4), wherein the boiling point difference between the organic solvent A and the organic solvent B is 20°C or higher and 100°C or lower.
(6) The organic semiconductor composition according to any one of (1) to (5) above, wherein the organic solvent A or organic solvent B is a compound having a cycloalkane as a substituent;
(7) The organic semiconductor composition according to any one of the preceding items (1) to (6), wherein the content of the organic solvent B is 10% by weight or more;
(8) The solubility of the organic semiconductor compound in the organic solvent A is 0.1% by weight or more, and the solubility of the organic semiconductor compound in the organic solvent B is less than 0.1% by weight. The organic semiconductor composition according to any one of
(9) Any one of the preceding items (1) to (8), wherein the solubility of the insulating compound in organic solvent A is 1% by weight or more and the solubility of the insulating compound in organic solvent B is less than 0.1% by weight. The organic semiconductor composition according to item 1,
(10) The organic semiconductor composition according to any one of (1) to (9) above, wherein the organic semiconductor compound is a compound having an acene skeleton, a phenacene skeleton or a heteroacene skeleton;
(11) The organic semiconductor composition according to (10) above, wherein the organic semiconductor compound is a compound having a thienothiophene skeleton;
(12) an organic thin film obtained by applying and drying the organic semiconductor composition according to any one of the preceding items (1) to (11); and (13) an organic having the organic thin film according to the preceding item (12) thin film transistor,
It is about.

By using the organic semiconductor composition of the present invention, a practical organic thin film transistor with high mobility and small variation in mobility can be obtained.

FIG. 1 is a schematic diagram of a droplet placed on a solid layer. FIG. 2 is a schematic diagram of a droplet placed on a solid layer. FIG. 3 is a schematic diagram of the sliding method. FIG. 4 is a schematic cross-sectional view showing some embodiments of the structure of the organic thin film transistor (element) of the present invention, where A is a bottom contact-bottom gate type organic thin film transistor (element), and B is a top contact-bottom gate type. Organic thin film transistor (device), C is top contact-top gate type organic thin film transistor (device), D is top and bottom gate type organic thin film transistor (device), E is static induction transistor (device), F is bottom contact-top gate type organic thin film transistor (device). FIG. 5 is an explanatory diagram for explaining the manufacturing process of a top-contact-bottom-gate organic thin-film transistor (element) as one embodiment of the organic thin-film transistor (element) of the present invention, and (1) to (6) are It is a schematic sectional drawing which shows each process.

The present invention will be described in detail.
The organic semiconductor composition of the present invention comprises an electrode substrate having an electrode comprising a substrate, an insulating compound layer comprising an insulating compound provided on the substrate, and a metal thin film layer provided on the insulating compound layer; and An organic semiconductor composition for forming an organic thin film of an organic thin film transistor element having an organic thin film layer containing an organic semiconductor compound provided on the electrode substrate,
Containing an organic semiconductor compound, an insulating compound, an organic solvent A that is a good solvent for the organic semiconductor compound and the insulating compound, and an organic solvent B that is a poor solvent for the organic semiconductor compound and the insulating compound,
In addition, the sliding angle of the organic solvent A solution having an insulating compound concentration of 1% by weight or more (hereinafter sometimes simply referred to as "insulating compound A solution") with respect to the insulating compound layer and the metal thin film layer is θ _{SUB (A ')} (°) and θ _{METAL (A')} (°), an insulating compound layer of a saturated organic solvent B solution of an insulating compound (hereinafter sometimes simply referred to as "insulating compound B solution") and metal It is an organic semiconductor composition that satisfies all of the following conditions (1) to (3) when the sliding angles with respect to the thin film layer are θ _{SUB (B')} (°) and θ _{METAL (B')} (°). .
Condition (1);
1°≦|θ _METAL(A′) −θ _SUB(A′) |
Condition (2):
1°≦|θ _METAL(B′) −θ _SUB(B′) |
Condition (3):
1°<||θ _METAL(A′) −θ _SUB(A′) |−|θ _METAL(B′) −θ _SUB(B′) ||

The organic semiconductor compound contained in the organic semiconductor composition of the present invention is a vapor deposition method or a solvent method (a solvent solution of the compound is applied to a substrate and then heated by mixing the compound alone or with other components if necessary). It means a compound from which a film obtained by forming a film by a film forming method in which a solvent is removed by a method such as the above exhibits semiconductor properties.
The organic semiconductor compound used in the organic semiconductor composition of the present invention is not limited to any of the low-molecular-weight organic semiconductor compounds and the high-molecular-weight organic semiconductor compounds generally referred to, but is preferably a low-molecular-weight organic semiconductor compound, and its molecular weight is is usually 1,500 or less, preferably 1,000 or less, more preferably 700 or less.
Also, the structure of the organic semiconductor compound is not particularly limited as long as it is known as an organic semiconductor compound.

Specific examples of organic semiconductor compounds include acene such as naphthacene, pentacene (2,3,6-dibenzoanthracene), hexacene, heptacene, dibenzopentacene, and tetrabenzopentacene, anthradithiophene, pyrene, benzopyrene, dibenzopyrene, chrysene, Compounds such as perylene, coronene, terylene, ovalene, quaterrylene and circamanthrasene; derivatives obtained by substituting some of the carbon atoms of the above compounds with atoms such as nitrogen, sulfur or oxygen; bonded to carbon atoms of the above compounds Derivatives in which at least one hydrogen atom is substituted with a functional group such as a carbonyl group (dioxaanthanthrene compounds including perixanthenoxanthene and its derivatives, tripenodioxazine, tripenodithiazine, hexacene-6,15-quinone, etc. ); and condensed polycyclic aromatic compounds such as derivatives in which the hydrogen atoms of the above compounds are substituted with other functional groups.

Further, as another specific example of the organic semiconductor compound, metal phthalocyanine represented by copper phthalocyanine, tetrathiapentalene and its derivatives, naphthalene-1,4,5,8-tetracarboxylic acid diimide, N,N'- Bis(4-trifluoromethylbenzyl)naphthalene-1,4,5,8-tetracarboxylic acid diimide, N,N'-(1H,1H-perfluorooctyl), N,N'-bis(1H,1H- perfluorobutyl), N,N'-dioctylnaphthalene-1,4,5,8-tetracarboxylic diimide derivatives, naphthalenetetracarboxylic diimides such as naphthalene-2,3,6,7-tetracarboxylic diimide, anthracene - not only compounds such as condensed ring tetracarboxylic diimide such as anthracenetetracarboxylic diimide such as 2,3,6,7-tetracarboxylic diimide, but also fullerenes such as C60, C80, C76, C84 and derivatives thereof, Examples include carbon nanotubes such as single-wall carbon nanotubes (SWNT), dyes such as merocyanine dyes and hexianine dyes, and derivatives thereof.
Additionally, organic semiconductor compounds may include polyanthracenes, triphenylenes and quinacridones.

Still other specific examples of organic semiconductor compounds include 4,4-biphenyldithiol (BPDT), 4,4-diisocyanobiphenyl, 4,4-diisocyano-p-terphenyl, 2,5-bis( 5′-thioacetyl-2′-thiophenyl)thiophene, 2,5-bis(thioacetoxyl-2′-thiophenyl)thiophene, 4,4′-diisocyanophenyl, benzidine (biphenyl-4,4′-diamine) , TCNQ (tetracyanoquinodimethane), tetrathiafulvalene (TIF) and its derivatives, tetrathiafulvalene (TTF)-TCNQ complex, bisethylenetetrathiafulvalene (BEDTTTF)-perchloric acid complex, BEDTTTF-iodine complex, TCNQ Field transfer complexes typified by iodine complexes, biphenyl-4,4'-dicarboxylic acid, 1,4-di(4-thiophenylacetynyl)-2-ethylbenzene, 1,4-di(4-isocyanophenylacetate) thinyl)-2-ethylbenzene, 2,2''-dihydroxy-1,1':4',1''-terphenyl, 4,4'-biphenyldiethanal, 4,4'-biphenyldiol, 4 ,4′-biphenyl diisocyanate, 1,4-diacetynylbenzene, diethylbiphenyl-4,4′-dicarboxylate, benzo[1,2-c;3,4-c′;5,6-c″ ] Tris[1,2]dithiol-1,4,7-trithione, α-sexithiophene, tetrathiatetracene, tetraselenotetracene, tetratellutetracene, poly(3-alkylthiophene), poly(3-thiophene-β -ethanesulfonic acid), poly(N-alkylpyrrole), poly(3-alkylpyrrole), poly(3,4-dialkylpyrrole), poly(2,2′-thienylpyrrole), poly(dibenzothiophenesulfide) can be mentioned.

The organic semiconductor compound used in the organic semiconductor composition of the present invention is preferably a condensed polycyclic aromatic compound, more preferably a condensed polycyclic aromatic compound having a phenacene skeleton, an acene skeleton or a heteroacene skeleton, and a condensed polycyclic aromatic compound having a heteroacene skeleton. A polycyclic aromatic compound is more preferred, a condensed polycyclic aromatic compound having a thienothiophene skeleton is particularly preferred, and a compound represented by the following formula (1) or (2) is most preferred.

In formula (1), R ₁ and R ₂ independently represent an aliphatic hydrocarbon group having 1 to 36 carbon atoms.
In formula (2), one of R ₃ and R ₄ represents an alkyl group, an aromatic hydrocarbon group having an alkyl group, or a heterocyclic group having an alkyl group, and the other represents an aliphatic hydrocarbon group or an aromatic hydrocarbon group. represents a hydrogen group or a heterocyclic group. However, the case where both R3 and _{R4 are} alkyl groups is excluded.

The aliphatic hydrocarbon group having 1 to 36 carbon atoms represented by R ₁ and R ₂ in formula (1) is a saturated or unsaturated aliphatic hydrocarbon group consisting only of 1 to 36 carbon atoms and hydrogen atoms. Although not limited to saturated, nor limited to linear, branched or cyclic, it is preferably a linear or branched aliphatic hydrocarbon group, more preferably a linear aliphatic hydrocarbon group. It is a hydrogen group. The aliphatic hydrocarbon group preferably has 2 to 24 carbon atoms, more preferably 4 to 20 carbon atoms, and still more preferably 6 to 12 carbon atoms.

Specific examples of linear or branched saturated aliphatic hydrocarbon groups include methyl group, ethyl group, propyl group, iso-propyl group, n-butyl group, iso-butyl group, t-butyl group, n-pentyl group, iso-pentyl group, t-pentyl group, sec-pentyl group, n-hexyl group, iso-hexyl group, n-heptyl group, sec-heptyl group, n-octyl group, n-nonyl group, sec-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-eicosyl group, docosyl group, n-pentacosyl group, n-octacosyl group, 5-(n-pentyl)decyl group, heneicosyl group, tricosyl group, tetracosyl group, hexacosyl group, heptacosyl group, nonacosyl group, n- triacontyl group, dotriacontyl group, hexatriacontyl group and the like.
Specific examples of cyclic saturated aliphatic hydrocarbon groups include cyclohexyl, cyclopentyl, adamantyl and norbornyl groups.

Specific examples of linear or branched unsaturated aliphatic hydrocarbon groups include vinyl, allyl, eicosadienyl, 11,14-eicosadienyl, geranyl (trans-3,7-dimethyl-2,6-octadiene -1-yl) group, farnesyl (trans, trans-3,7,11-trimethyl-2,6,10-dodecatrien-1-yl) group, 4-pentenyl group, 1-propynyl group, 1-hexynyl group , 1-octynyl group, 1-decynyl group, 1-undecynyl group, 1-dodecynyl group, 1-tetradecynyl group, 1-hexadecynyl group and 1-nonadecynyl group.

A hydrogen atom in the aliphatic hydrocarbon group having 1 to 36 carbon atoms represented by R ₁ and R ₂ in formula (1) may be substituted with a halogen atom. Halogen atoms that can be substituted for hydrogen include fluorine, chlorine, bromine and iodine atoms, preferably fluorine, chlorine or bromine, more preferably fluorine or bromine. Specific examples of halogeno-substituted aliphatic hydrocarbon groups in which a hydrogen atom is substituted with a halogen atom include a chloromethyl group, a bromomethyl group, a trifluoromethyl group, a pentafluoroethyl group, an n-perfluoropropyl group, and an n-perfluorobutyl group. , n-perfluoropentyl group, n-perfluorooctyl group, n-perfluorodecyl group, n-(dodecafluoro)-6-iodohexyl, 2,2,3,3,3-pentafluoropropyl group and 2,2, 3,3-tetrafluoropropyl group and the like.

As the compound represented by the formula (1), a combination of preferable R ₁ and R ₂ is more preferable, and a combination of more preferable R 1 and R 2 is even more preferable.
Specifically, R ₁ and R ₂ are each independently a linear or branched aliphatic hydrocarbon group having 2 to 24 carbon atoms or a linear or branched halogeno-substituted aliphatic hydrocarbon group having 2 to 24 carbon atoms. is preferably a straight or branched chain aliphatic hydrocarbon group having 4 to 20 carbon atoms or a straight or branched chain halogeno-substituted aliphatic hydrocarbon group having 4 to 20 carbon atoms. Certain compounds are more preferred, and compounds that are straight or branched chain aliphatic hydrocarbon groups having 6 to 12 carbon atoms or straight or branched chain halogeno-substituted aliphatic hydrocarbon groups having 6 to 12 carbon atoms are further preferred. Compounds that are preferably straight-chain aliphatic hydrocarbon groups of 6 to 12 carbon atoms or straight-chain halogeno-substituted aliphatic hydrocarbon groups of 6 to 12 carbon atoms are more preferred. R ₁ and R ₂ may be the same or different.

The alkyl group represented by R ₃ or R ₄ in formula (2) is not limited to any of linear, branched and cyclic, and specific examples thereof include methyl, ethyl, propyl, isopropyl, n -butyl group, iso-butyl group, allyl group, t-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-cetyl group, n-heptadecyl group, n-butenyl group, 2-ethylhexyl group, 3-ethylheptyl group, 4-ethyloctyl group, 2-butyloctyl group, 3-butylnonyl group, 4-butyldecyl group, 2-hexyldecyl group, 3-octylundecyl group, 4-octyldodecyl group, 2-octyldodecyl group, 2-decyltetradecyl group, cyclohexyl group, cyclopentyl group, adamantyl group and norbornyl group. Linear or branched groups such as n-butyl group, n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, ethylhexyl group, ethyloctyl group, butyloctyl group and hexyldecyl group are preferable. and more preferably n-hexyl group, n-octyl group, n-decyl group, 2-ethylhexyl group, 3-ethylhexyl group, 3-ethyloctyl group or 3-butyloctyl group.

The alkyl group represented by R ₃ or R ₄ in formula (2) is preferably a linear or branched alkyl group having 2 to 16 carbon atoms, more preferably a linear or branched alkyl group having 4 to 12 carbon atoms. Preferably, a linear alkyl group having 4 to 10 carbon atoms or a branched alkyl group having 6 to 12 carbon atoms is more preferable, and a linear or branched alkyl group having 6 to 10 carbon atoms is particularly preferable. 10 straight chain alkyl groups are most preferred.

The aromatic hydrocarbon group in the aromatic hydrocarbon group having an alkyl group represented by R ₃ or R ₄ in formula (2) means a residue obtained by removing one hydrogen atom from an aromatic hydrocarbon, and the aromatic Specific examples of group hydrocarbon groups include phenyl, naphthyl, anthryl, phenanthryl, pyrenyl and benzopyrenyl groups.
The aromatic hydrocarbon group in the aromatic hydrocarbon group having an alkyl group represented by R ₃ or R ₄ in formula (2) is preferably a phenyl group or a naphthyl group, more preferably a phenyl group.

Examples of the alkyl group in the aromatic hydrocarbon group having an alkyl group represented by R ₃ or R ₄ in formula (2) include those similar to the alkyl group represented by R ₃ or R ₄ in formula (2). It is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably a linear or branched alkyl group having 1 to 6 carbon atoms, and a linear alkyl group having 1 to 6 carbon atoms more preferably a group.

Although the substitution position of the alkyl group on the aromatic hydrocarbon group in the aromatic hydrocarbon group having an alkyl group represented by R ₃ or R ₄ in formula (2) is not particularly limited, for example, when the aromatic hydrocarbon group is a phenyl group In the case of , it is a preferred embodiment that the alkyl group is substituted at the 4-position.

The heterocyclic group in the heterocyclic group having an alkyl group represented by R ₃ or R ₄ of formula (2) means a residue obtained by removing one hydrogen atom from the heterocyclic ring, and specific examples of the heterocyclic group are is pyridyl group, pyrazyl group, pyrimidyl group, quinolyl group, isoquinolyl group, pyrrolyl group, indolenyl group, imidazolyl group, carbazolyl group, thienyl group, furyl group, pyranyl group, pyridonyl group, benzoquinolyl group, anthraquinolyl group, benzothienyl group , benzofuryl group, and thienothienyl group.

The heterocyclic group in the heterocyclic group having an alkyl group represented by R ₃ or R ₄ in formula (2) is preferably a pyridyl group, a thienyl group, a benzothienyl group or a thienotienyl group, more preferably a thienyl group or a benzothienyl group. , a thienyl group is more preferred.

Examples of the alkyl group in the heterocyclic group having an alkyl group represented by R ₃ or R ₄ in formula (2) include those similar to the alkyl group represented by R ₃ or R ₄ in formula (2), and having 1 carbon atom. A linear or branched alkyl group having 4 to 8 carbon atoms is preferable, and a linear or branched alkyl group having 4 to 8 carbon atoms is preferable. It is more preferable to have

The aliphatic hydrocarbon group represented by R ₃ or R ₄ in formula (2) (an aliphatic hydrocarbon group represented by the other) is the same as the aliphatic hydrocarbon group represented by R ₁ and R ₂ in formula (1). and the aliphatic hydrocarbon group preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and still more preferably 4 to 16 carbon atoms. Specifically, saturated groups such as n-butyl group, n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, ethylhexyl group, ethyloctyl group, butyloctyl group and hexyldecyl group. A linear or branched alkyl group is preferred, and an n-hexyl group, n-octyl group, n-decyl group, 2-ethylhexyl group, 3-ethylhexyl group or 3-ethyloctyl group is more preferred.

As the aromatic hydrocarbon group represented by R ₃ or R ₄ in formula (2) (an aromatic hydrocarbon group represented by the other), an aromatic hydrocarbon having an alkyl group represented by R ₃ or R ₄ in formula (2) Examples thereof include the same aromatic hydrocarbon groups as described in the section of the group, preferably a phenyl group, a naphthyl group or a pyridyl group, more preferably a phenyl group or a naphthyl group, and still more preferably a phenyl group.

The heterocyclic group represented by R ₃ or R ₄ (heterocyclic group represented by the other) in formula (2) is described in the section of the heterocyclic group having an alkyl group represented by R ₃ or R ₄ in formula (2). Examples thereof include the same heterocyclic groups, preferably a pyridyl group, a thienyl group or a benzothienyl group, more preferably a thienyl group or a benzothienyl group.

The aromatic hydrocarbon group (aromatic hydrocarbon group represented by the other) and the heterocyclic group (heterocyclic group represented by the other) represented by R ₃ or R ₄ in formula (2) may have a substituent. Examples of the substituents which may be present include the same alkyl groups represented by R ₃ or R ₄ in formula (2), preferably linear or branched alkyl groups having 1 to 6 carbon atoms, A straight-chain alkyl group having 1 to 6 carbon atoms is more preferred.

As the compound represented by the formula (2), a combination of the preferred R ₃ and R ₄ described above is more preferred, and a combination of the more preferred ones of each is even more preferred.
Specifically, one of R ₃ and R ₄ is a phenyl group having a linear or branched alkyl group having 1 to 10 carbon atoms or a linear or branched alkyl group having 1 to 16 carbon atoms, and the other is preferably a phenyl group, pyridyl group, thienyl group or benzothienyl group optionally having a straight or branched alkyl group having 1 to 6 carbon atoms, one of which is a straight chain having 4 to 16 carbon atoms or a branched alkyl group, and the other is more preferably a phenyl group, a thienyl group, or a benzothienyl group optionally having a straight or branched alkyl group having 1 to 6 carbon atoms, and one is A compound that is a straight or branched chain alkyl group having 4 to 12 carbon atoms and the other is a phenyl group or a benzothienyl group that may have a straight or branched chain alkyl group having 1 to 6 carbon atoms is more preferable, one is a straight-chain alkyl group having 4 to 10 carbon atoms or a branched-chain alkyl group having 6 to 12 carbon atoms, and the other is a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms A compound which is an optionally phenyl group is particularly preferred, and a compound in which one is a linear alkyl group having 6 to 10 carbon atoms and the other is a phenyl group is most preferred.

The content of the organic semiconductor compound in the organic semiconductor composition of the present invention is preferably in the range of 0.1 to 20% by weight, more preferably 0.2 to 15% by weight, still more preferably 0.3 to 10% by weight. be. In this specification, "%" means "% by weight" and "parts" means "parts by weight" unless otherwise specified.

The insulating compound contained in the organic semiconductor composition of the present invention means a compound other than a compound having conductivity and a compound having semiconductor properties, and its structure and molecular weight are not particularly limited. Polymer compounds can be preferably used.
Examples of insulating organic polymer compounds include polyvinyl carboxylate, polyvinyl acetal, polystyrene, polyvinyl naphthalene, polycarbonate, polyarylate, polyester, polyamide, polyimide, polyurethane, polysiloxane, polysulfone, polymethyl methacrylate, cellulose, polyethylene, and polypropylene. , and copolymers, rubbers or thermoplastic elastomers thereof are preferred, and polyvinyl carboxylate, polyvinyl acetal, polystyrene, polymethyl methacrylate or polymethyl acrylate is more preferred.
That is, the insulating compound is preferably a compound having repeating units represented by the following formulas (3) and/or (4).

In formulas (3) and (4), R ₅ to R ₈ represent linear or branched alkyl groups having 1 to 20 carbon atoms.
R ₅ and R ₆ in formula (3) are preferably linear or branched alkyl groups having 1 to 10 carbon atoms, more preferably linear or branched alkyl groups having 1 to 6 carbon atoms. It is preferably a straight-chain alkyl group having 2 to 4 carbon atoms, more preferably a methyl group.
R ₇ and R ₈ in formula (4) are preferably linear or branched alkyl groups having 1 to 10 carbon atoms, more preferably linear alkyl groups having 1 to 6 carbon atoms.

A compound having a repeating unit represented by the following formula (5) is also preferable as the insulating compound.

_In formula ( ₅ ), R9 and R10 each independently represent a hydrogen atom, a hydroxy group, an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, or a halogen atom.
R ₉ and R ₁₀ in formula (5) are preferably a straight or branched chain alkyl group having 1 to 10 carbon atoms or a hydrogen atom, and a straight or branched chain alkyl group having 1 to 6 carbon atoms or hydrogen It is more preferably an atom, more preferably a linear alkyl group having 1 to 4 carbon atoms or a hydrogen atom, particularly preferably a hydrogen atom.

As the insulating compound, a compound having a repeating unit represented by the following formula (6) is also preferable.

In formula (6), R ₁₁ represents a hydrogen atom or an alkyl group. R ₁₂ to R ₁₆ each independently represent a hydrogen atom, a hydroxy group, an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, or a halogen atom, and R ₁₂ to R ₁₆ are adjacent The two may be linked together to form a ring.
R ₁₂ to R ₁₆ in formula (6) preferably have a linear or branched chain alkyl group having 1 to 8 carbon atoms or a hydrogen atom, and two adjacent groups are preferably linked to each other to form a ring. More preferably, 1 to 6 straight or branched chain alkyl groups or hydrogen atoms, or two adjacent ones thereof are linked to each other to form a ring, most preferably a naphthalene structure.

As the insulating compound, a compound having a repeating unit represented by the following formula (7) is also preferable.

In formula ₍ 7), R17 represents a hydrogen atom or an alkyl group. R ₁₈ to R ₂₂ each independently represent a hydrogen atom, a hydroxy group, an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, or a halogen atom, and R ₁₈ to R ₂₂ are adjacent The two may be linked together to form a ring.
R ₁₈ to R ₂₂ in formula (7) preferably have a straight or branched chain alkyl group having 1 to 8 carbon atoms or a hydrogen atom, and two adjacent groups are preferably linked to each other to form a ring. More preferably, 1 to 6 straight or branched chain alkyl groups or hydrogen atoms, or two adjacent ones thereof are linked to each other to form a ring, most preferably a naphthalene structure.

As the insulating compound, a compound having a repeating unit represented by the following formula (8) is also preferable.

In formula (7), R ₂₃ and R ₂₄ each independently represent a hydrogen atom, a hydroxy group, an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group, or a halogen atom.

Although the molecular weight of the insulating compound is not particularly limited, it is preferably an insulating organic polymer compound, and the insulating organic polymer compound contains at least one repeating unit represented by the above formulas (3) to (8). It is more preferable to have The weight average molecular weight of the insulating organic polymer compound is preferably 1,000 to 5,000,000, more preferably 5,000 to 2,500,000, and more preferably 10,000 to 2,000,000. is more preferred. In addition, the weight average molecular weight in this specification means the value calculated by polystyrene conversion based on the measurement result of GPC.

The content of the insulating compound in the organic semiconductor composition of the present invention is preferably in the range of 0.01 to 10% by weight, more preferably 0.02 to 5% by weight, still more preferably 0.05 to 1% by weight. be.

The organic solvent A contained in the organic semiconductor composition of the present invention is a good solvent for the organic semiconductor and the insulating compound contained in the organic semiconductor composition of the present invention, and the organic solvent B is for the organic semiconductor and the insulating compound. It is a poor solvent. In this specification, the term "good solvent for the organic semiconductor compound and the insulating compound" means a solvent in which 0.1 part or more of the organic semiconductor compound and the organic semiconductor compound are dissolved in 100 parts of the solvent. and "poor solvent for the insulating compound" means a solvent in which less than 0.1 parts of the organic semiconductor compound and the insulating compound are dissolved in 100 parts of the solvent.

The organic solvent A is a good solvent for organic semiconductor compounds, and its solubility is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and even more preferably 0.5% by weight or more.

The organic solvent A is a good solvent for insulating compounds, and its solubility is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and even more preferably 1% by weight or more.

The organic solvent B is a poor solvent for the organic semiconductor compound, and preferably has a solubility of less than 0.1% by weight.

The organic solvent B is a poor solvent for the insulating compound, and preferably has a solubility of less than 0.1% by weight.

The boiling points of organic solvent A and organic solvent B are not particularly limited as long as there is a boiling point difference between organic solvent A and organic solvent B. It is necessary to consider the compositional stability under the conditions, and the boiling point of at least one solvent is preferably 140°C or higher, more preferably 170°C or higher.
The difference in boiling points between organic solvent A and organic solvent B is preferably 1° C. or more, more preferably 5° C. or more, still more preferably 10° C. or more and 130° C. or less, and 15° C. or more and 100° C. or less. It is particularly preferable that the temperature is 20° C. or more and 100° C. or less.

When a compound having repeating units of formula (3) and/or formula (4) (such as PMMA) is used as the insulating compound, the organic solvent A is a solvent made of a compound having an ether group or an ester group. An aromatic solvent having an ether group or an ester group is more preferred. and aromatic ether solvents such as ethyl benzoate, butyl benzoate, methyl benzoate, benzyl benzoate, phenyl acetate and benzyl acetate. Solvent B in this case is preferably a solvent made of a hydrocarbon compound, a solvent having a hydroxyl group, or a solvent having a ketone group. more preferably a solvent having a More preferred are tetralin, butylcyclohexane and butylcyclopentane.

When a compound having repeating units represented by the above formulas (5) to (8) (for example, polystyrene, polyvinylnaphthalene, etc.) is used as the insulating compound, the organic solvent A is a solvent made of a hydrocarbon compound, an ether group, or a carbonyl is preferably a solvent composed of a compound having a , triethylbenzene, cyclohexylbenzene, tetralin, anisole, anethole, methylanisole, dimethylanisole, trichloroanisole, dichloroanisole, bromoanisole and fluoroanisole, phenetole, methylphenetole, ethyl benzoate, butyl benzoate, methyl benzoate, Benzyl benzoate, phenyl acetate and benzyl acetate are more preferred. In this case, the organic solvent B is preferably a solvent composed of a hydrocarbon compound or a solvent composed of a hydroxyl group, and a solvent composed of a hydrocarbon compound having no aromaticity or a solvent having a hydroxyl group having no aromaticity is more preferable. Solvents composed of hydrocarbon compounds having a cycloalkane as a substituent and having no aromaticity are preferred, and solvents having a hydroxyl group having a cycloalkane and having no aromaticity are more preferred, such as cyclooctane, cyclononane, cyclodecane, and bicyclohexyl. , butylcyclohexane, butylcyclopentane, decalin, cyclohexanol, cycloheptanol, cyclooctanol are most preferred.

The organic solvent A and the organic solvent B contained in the organic semiconductor composition of the present invention have a difference in wettability with respect to the insulating compound layer and wettability with respect to the metal thin film layer partially provided on the insulating compound layer. Some are preferred. A contact angle (static contact angle and dynamic contact angle) is generally used as an index of the wettability of a liquid to a solid layer.

FIG. 1 is a schematic diagram of a droplet placed on a solid layer. The contact angle quantifies the extent of wetting and is defined as the angle between the liquid surface and the solid surface where the free surface of a stationary liquid touches the solid wall (the angle inside the liquid). .
When a liquid is dropped onto a solid surface, the liquid becomes round due to its own surface tension, and the equation shown in FIG. 1 holds. This formula is called Young's formula. In FIG. 1, the angle θ between the tangent line of the droplet and the solid surface is called the contact angle. Methods for measuring the contact angle include, for example, the θ/2 method, the tangent method, and the curve fitting method, and the θ/2 method is generally used.
According to the θ/2 method, the contact angle can be obtained by obtaining the radius r and the height h of the droplet shown in FIG. 2 and substituting them into the following equation.

In the θ/2 method, the contact angle can be obtained by obtaining the angle of the straight line connecting the left and right end points and the vertex of the droplet with respect to the solid surface and doubling this angle. Since the θ/2 method assumes that the droplet is part of a sphere, the droplet volume is measured with negligible effects of gravity. If you have a scale like a protractor, you can measure directly. Even if the analysis is performed by a personal computer, the calculation can be done in a very short time because the calculation is simple.

In the tangent method, the vicinity of the droplet end point can be regarded as a part of a sphere, the center of the circle can be obtained from several points existing on the arc, and the tangent line of the circle at the point on the arc can be obtained. The contact angle is the angle between the tangent to the circle and the straight line. Since the θ/2 method calculates the contact angle from the width and height of the captured droplet, the obtained contact angle is the average value of the left and right sides. On the other hand, the tangent method can determine the contact angle separately for the left and right sides, and is a more effective measurement method when the values for the right and left sides of the droplet vary due to the state of the solid surface.

In the curve fitting method, it is assumed that the contour shape of the droplet forms a part of a perfect circle or an ellipse, and the least-squares fitting is performed using all observation coordinates within a specified interval (fitting interval). By this calculation, the parameters of the perfect circle or ellipse are determined, and the differential coefficient at the end points is obtained to calculate the contact angle.

The contact angle described in the previous section is a static contact angle on the premise that the droplet is stationary on a solid surface. Can be used for mutual comparison.
However, assuming that the liquid-solid interface is moving in various situations, such as coating and washing, dynamic situations where the droplet interface moves (having an advancing contact angle and a receding contact angle) need to be simulated. Therefore, the method for measuring the dynamic contact angle will now be described in detail.

Dynamic contact angles include advancing and receding angles. Methods for measuring dynamic contact angles include, for example, the drop method (change over time), the expansion/contraction method, the slide-down method, and the Wilhelmy method.
The droplet method (change over time) continuously measures the contact angle described in the previous section, and can also be used for the purpose of tracking the state of absorption and volatilization.
The expansion/contraction method measures the contact angle (advancing contact angle and receding contact angle) when the droplet interface advances and recedes by inflating or sucking the droplet in contact with the solid surface.
The sliding method is a method in which a solid sample on which a droplet is placed is tilted to allow the droplet to slide. FIG. 3 is a schematic diagram thereof, and the sliding angle, the advancing angle, and the receding angle are the angles shown in FIG. 3, respectively.
In the Wilhelmy method, the load is measured in the process of submerging a solid sample in a liquid sample in a sample tank and in the process of lifting the submerged sample, and the dynamic contact angle is calculated from the measured value and the value of the surface area of the solid sample. It is a method of asking.

In this specification, using an organic solvent A solution with an insulating compound concentration of 1% by weight or more and a saturated organic solvent B solution of an insulating compound, the static contact angle is measured by the θ / 2 method, and the dynamic contact angle is measured by sliding down. measured by the method.

The insulating compound and organic solvents A and B contained in the organic semiconductor composition of the present invention are such that the sliding angle of the insulating compound A solution with respect to the insulating compound layer and the metal thin film layer is θ _{SUB (A′)} (°) and θ _{When METAL (A')} (°) and the sliding angle of the insulating compound B solution with respect to the insulating compound layer and the metal thin film layer are θ _{SUB (B')} (°) and θ _{METAL (B')} (°) , the following conditions (1) to (3)
Condition (1);
1°≦|θ _METAL(A′) −θ _SUB(A′) |
Condition (2):
1°≦|θ _METAL(B′) −θ _SUB(B′) |
Condition (3):
1°<||θ _METAL(A′) −θ _SUB(A′) |−|θ _METAL(B′) −θ _SUB(B′) ||
It is an organic semiconductor composition that satisfies all the relationships of
The condition (1) referred to here is the sliding angle (unit is "°") of the insulating compound A solution with respect to the metal thin film layer from the sliding angle (unit is "°") of the insulating compound A solution with respect to the insulating compound layer. is the absolute value (unit is "°") of the value obtained by subtracting the insulating compound B solution from the sliding angle (unit is "°") of the insulating compound B solution with respect to the metal thin film layer. It is the absolute value (unit is “°”) of the value obtained by subtracting the sliding angle (unit is “°”) with respect to the insulating compound layer, and condition (3) is the absolute value of condition (1) to condition (2) is the absolute value (unit is "°") of the value obtained by subtracting the absolute value of

The absolute value of condition (1) is preferably 1° or more and 40° or less, more preferably 10° or more and 30° or less. Further, when the absolute value of condition (2) is 1° or more and 40° or less, it is also a more preferable aspect that the absolute value of condition (1) is 1° or more and 20° or less or 20° or more and 40° or less. be.
The absolute value of condition (2) is preferably 1° or more and 40° or less, more preferably 5° or more and 35° or less.
The absolute value of condition (3) is preferably more than 1° and less than 35°.
It should be noted that a combination of the preferred absolute value ranges of the conditions (1) to (3) described above is more preferred, and a more preferred combination of absolute values is even more preferred.

Also, the static contact angles of the insulating compound A solution with respect to the insulating compound layer and the metal thin film layer are α _{SUB (A′)} (°) and α _{METAL (A′)} (°), and the insulator of the insulating compound B solution When the static contact angles for the compound layer and the metal thin film layer are α _{SUB (B')} (°) and α _{METAL (B')} (°), the following conditions (I) and (II)
Condition (I);
1°≦|α _METAL(A′) −α _SUB(A′) |
Condition (II);
1°≦|α _METAL(B′) −α _SUB(B′) |
It is also preferable that the organic semiconductor composition satisfies all the relationships of
The condition (I) here refers to the static contact angle (unit is "°") of the insulating compound A solution to the metal thin film layer from the static contact angle (unit is "°") is the absolute value (unit is "°"), and the condition (2) is the static contact angle (unit is "°") of the insulating compound B solution with respect to the metal thin film layer. It is the absolute value (unit: "°") of the value obtained by subtracting the static contact angle (unit: "°") of the insulating compound B solution with respect to the insulating compound layer.
The absolute value of condition (I) is more preferably 1° or more and 40° or less, and still more preferably 10° or more and 30° or less. Further, the absolute value of condition (II) is more preferably 1° or more and 40° or less, and still more preferably 5° or more and 35° or less.
It should be noted that a combination of more preferable absolute value ranges of the conditions (I) and (II) described above is more preferable, and a still more preferable combination of absolute values is particularly preferable.

Preferred specific examples of the organic solvent A and the organic solvent B contained in the organic semiconductor composition of the present invention are shown in Tables 1 to 8 below. Tables 1, 2, 5 and 6 are the contact angles in the insulating compound layer measured by the method described in Reference Example 2 in Examples using the insulating compounds listed in the tables. 3, 4, 7 and 8 are the contact angles with respect to the metal thin film layer measured according to the method described in Reference Example 3 in Examples using the insulating compounds described in the table.

The organic solvent A and the organic solvent B are not limited to the preferred specific examples described above, and an appropriate solvent may be selected depending on the types of the organic semiconductor compound and the insulating compound within the range satisfying the various conditions described above.

The content ratio of the organic solvent B in the organic semiconductor composition of the present invention is preferably 50% or less, more preferably 40% or less, still more preferably 30% or less, and 10% or more and 20% or less. is most preferred.

The method for producing the organic semiconductor composition of the present invention is not particularly limited, and known methods can be employed. For example, a desired composition can be obtained by sequentially adding predetermined amounts of an organic semiconductor compound and an insulating compound to a mixed solvent of organic solvent A and organic solvent B, and appropriately stirring the mixture.

The organic thin film (organic semiconductor film) of the present invention is produced by forming an organic semiconductor composition layer by usually coating or printing the organic semiconductor composition of the present invention on a substrate, and then heat-treating the composition layer. can get. Conventionally known methods can be employed without particular limitation for coating or printing. The heat treatment method and conditions are not particularly limited as long as the organic solvents A and B can be evaporated, but it is preferable to perform the heat treatment under reduced pressure in order to lower the drying temperature.

The organic thin film transistor of the present invention has two electrodes (a source electrode and a drain electrode) in contact with the organic semiconductor film of the present invention, and the current flowing between the electrodes is a voltage applied to another electrode called a gate electrode. control.

A structure in which a gate electrode is insulated by an insulating film (Metal-Insuulator-Semiconductor MIS structure) is generally used for an organic thin film transistor device. A structure in which a metal oxide film is used as an insulating film is called a MOS structure, and a structure in which a gate electrode is formed via a Schottky barrier (that is, an MES structure) is also known. , MIS structures are often used.

4, 1 is a source electrode, 2 is an organic thin film (semiconductor layer), 3 is a drain electrode, 4 is an insulator layer, 5 is a gate electrode, and 6 is a substrate. The arrangement of each layer and electrodes can be appropriately selected according to the application of the device. A to D and F are called lateral transistors because the current flows parallel to the substrate. A is called a bottom contact bottom gate structure, and B is called a top contact bottom gate structure. In C, source and drain electrodes and an insulator layer are provided on a semiconductor, and a gate electrode is further formed thereon, which is called a top-contact top-gate structure. D is a structure called a top & bottom contact bottom gate type transistor. F is a bottom contact top gate structure. E is a schematic diagram of a transistor with a vertical structure, that is, a static induction transistor (SIT). In this SIT, a large amount of carriers can move at once because the current flow spreads in a plane. In addition, since the source electrode and the drain electrode are arranged vertically, the distance between the electrodes can be reduced, resulting in high speed response. Therefore, it can be preferably applied to applications such as high-speed switching and large current flow. Although the substrate is not shown in E in FIG. 4, the substrate is usually provided outside the source or drain electrodes indicated by 1 and 3 in FIG. 4E.

Each component in each embodiment will be described. The substrate 6 needs to be able to hold each layer formed thereon without peeling off. For example, insulating materials such as resin plates, films, paper, glass, quartz, and ceramics; objects in which an insulating layer is formed by coating or the like on a conductive substrate such as a metal or alloy; materials made of various combinations such as resins and inorganic materials; etc. can be used. Examples of usable resin films include polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyamide, polyimide, polycarbonate, cellulose triacetate and polyetherimide. The use of a resin film or paper makes the device flexible, lightweight, and practical. The thickness of the substrate is usually 1 μm to 10 mm, preferably 5 μm to 5 mm.

A material having conductivity is used for the source electrode 1 , the drain electrode 3 , and the gate electrode 5 . Metals such as platinum, gold, silver, aluminum, chromium, tungsten, tantalum, nickel, cobalt, copper, iron, lead, tin, titanium, indium, palladium, molybdenum, magnesium, calcium, barium, lithium, potassium, sodium, etc. and alloys containing them; conductive oxides such as InO ₂ , ZnO ₂ , SnO ₂ and ITO; conductive high molecular compounds such as polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylenevinylene, and polydiacetylene; Semiconductors such as gallium arsenide; carbon materials such as carbon black, fullerene, carbon nanotubes, graphite and graphene; and the like can be used. Also, the conductive polymer compound and the semiconductor may be doped. Examples of dopants include inorganic acids such as hydrochloric acid and sulfuric acid; organic acids having an acidic functional group such as sulfonic acid; Lewis acids such as _{PF5 , AsF5} and FeCl3; halogen atoms such as iodine; metal atoms such as; Boron, phosphorus, arsenic and the like are also frequently used as dopants for inorganic semiconductors such as silicon.

A conductive composite material in which carbon black, metal particles, or the like is dispersed in the above dopant is also used. For the source electrode 1 and the drain electrode 3, which are in direct contact with the semiconductor, it is important to select an appropriate work function or perform surface treatment in order to reduce contact resistance.

Moreover, the distance (channel length) between the source electrode and the drain electrode is an important factor in determining device characteristics, and an appropriate channel length is required. If the channel length is short, the amount of current that can be extracted increases, but the short channel effect such as the influence of the contact resistance occurs, and the semiconductor characteristics may deteriorate. The channel length is typically 0.01 to 300 μm, preferably 0.1 to 100 μm. The width (channel width) between the source and drain electrodes is usually 10 to 5000 μm, preferably 40 to 2000 μm. In addition, it is possible to form a longer channel width by using a comb-shaped electrode structure. be.

Each structure (shape) of the source electrode and the drain electrode will be described. The structures of the source and drain electrodes may be the same or different.

In the case of the bottom contact structure, each electrode is generally fabricated using a lithographic method, and each electrode is preferably formed into a rectangular parallelepiped. Recently, the printing accuracy of various printing methods has been improved, and it has become possible to produce electrodes with high accuracy using methods such as inkjet printing, gravure printing, and screen printing. In the case of a top contact structure in which an electrode is placed on a semiconductor, vapor deposition can be performed using a shadow mask or the like. It has also become possible to directly print an electrode pattern using a technique such as inkjet. The electrode length is the same as the channel width described above. Although the width of the electrode is not particularly defined, it is preferably as short as possible in order to reduce the area of the device as long as the electrical characteristics can be stabilized. The width of the electrodes is usually 0.1 to 1000 μm, preferably 0.5 to 100 μm. The thickness of the electrode is usually 0.1 to 1000 nm, preferably 1 to 500 nm, more preferably 5 to 200 nm. Wires are connected to the electrodes 1, 3, and 5, and the wires are also made of substantially the same material as the electrodes.

A material having insulating properties is used as the insulator layer 4 . For example, polyparaxylylene, polyacrylate, polymethylmethacrylate, polystyrene, polyvinylphenol, polyamide, polyimide, polycarbonate, polyester, polyvinyl alcohol, polyvinyl acetate, polyurethane, polysulfone, polysiloxane, polyolefin, fluororesin, epoxy resin, phenol Polymers such as resins and copolymers thereof; metal oxides such as silicon oxide, aluminum oxide _, titanium oxide and tantalum oxide; ferroelectric metal oxides such as SrTiO3 and BaTiO3; silicon nitride _, aluminum nitride and the like dielectrics such as nitrides, sulfides, fluorides, etc.; or polymers in which particles of these dielectrics are dispersed; For this insulator layer, one having high electrical insulation properties can be preferably used in order to reduce leakage current. As a result, the film thickness can be reduced, the insulation capacity can be increased, and more current can be taken out. Moreover, in order to improve the mobility of the semiconductor, it is preferable that the surface energy of the insulating layer surface is lowered and the film is smooth without unevenness. Therefore, a self-assembled monolayer or a two-layered insulator layer may be formed. The thickness of the insulator layer 4 varies depending on the material, but is usually 0.1 nm to 100 μm, preferably 0.5 nm to 50 μm, more preferably 1 nm to 10 μm.

The organic semiconductor composition of the present invention is used as the material of the semiconductor layer 2 . The semiconductor layer 2 can be formed by forming an organic semiconductor film by a method according to the method for forming the organic semiconductor film described above.

The semiconductor layer (organic thin film) may have a plurality of layers, but preferably has a single-layer structure. It is preferable that the film thickness of the semiconductor layer 2 is as thin as possible as long as the necessary functions are not lost. In horizontal organic transistors as shown in A, B and D, the device characteristics do not depend on the film thickness if the film thickness exceeds a predetermined value, but leakage current often increases as the film thickness increases. It's for. The thickness of the semiconductor layer for exhibiting necessary functions is usually 1 nm to 1 μm, preferably 5 nm to 500 nm, more preferably 10 nm to 300 nm.

In the organic thin film transistor, other layers may be provided, for example, between the substrate layer and the insulating film layer, between the insulating film layer and the semiconductor layer, or on the outer surface of the device, if necessary. For example, if a protective layer is formed directly on the organic thin film or via another layer, the influence of outside air such as humidity can be reduced. It also has the advantage of stabilizing the electrical characteristics, such as increasing the on/off ratio of the organic transistor device.

The material of the protective layer is not particularly limited, but for example, films made of various resins such as epoxy resin, acrylic resin such as polymethyl methacrylate, polyurethane, polyimide, polyvinyl alcohol, fluororesin, polyolefin; silicon oxide, aluminum oxide, nitride Inorganic oxide films such as silicon; films made of dielectrics such as nitride films; Gas barrier protective materials developed for organic EL displays can also be used. Although the film thickness of the protective layer can be selected according to its purpose, it is usually 100 nm to 1 mm.

Further, by subjecting the substrate or insulator layer on which the organic thin film is to be laminated to surface modification or surface treatment in advance, it is possible to improve the characteristics as an organic transistor device. For example, by adjusting the degree of hydrophilicity/hydrophobicity of the substrate surface, it is possible to improve the film quality and film-forming properties of the film formed thereon. In particular, the properties of organic semiconductor materials may vary greatly depending on the state of the film, such as molecular orientation. Therefore, the surface treatment of the substrate, insulator layer, etc. controls the molecular orientation at the interface with the subsequently deposited organic thin film, or reduces the trap sites on the substrate or insulator layer. , carrier mobility, etc. are considered to be improved.

A trapping site refers to a functional group, such as a hydroxyl group, present in the untreated substrate, the presence of which electrons are attracted to the functional group, resulting in reduced carrier mobility. . Therefore, reducing the number of trap sites is often effective in improving characteristics such as carrier mobility.

Examples of surface treatments for improving properties as described above include self-assembled monolayer treatments with hexamethyldisilazane, octyltrichlorosilane, octadecyltrichlorosilane, etc., surface treatments with polymers, etc., hydrochloric acid, sulfuric acid, acetic acid, etc. acid treatment, alkali treatment with sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, etc., ozone treatment, fluorination treatment, plasma treatment with oxygen, argon, etc., formation of Langmuir-Blodgett film, other insulators , semiconductor thin film forming treatment, mechanical treatment, electrical treatment such as corona discharge, rubbing treatment using fibers, etc., and a combination of these treatments can also be performed.

In these embodiments, for example, the above-described vacuum process and solution process can be appropriately adopted as a method of providing each layer such as a substrate layer and an insulating film layer or an insulating film layer and an organic thin film.

Next, the method for manufacturing the organic thin film transistor device of the present invention will be described below with reference to FIG. 2, taking the top-contact bottom-gate type organic transistor shown in Embodiment B of FIG. 1 as an example. This manufacturing method can be similarly applied to the organic transistors of other embodiments described above.

(Regarding organic transistor substrates and substrate processing)
The organic transistor of the present invention is produced by providing various necessary layers and electrodes on the substrate 6 (see FIG. 5(1)). As the substrate, those described above can be used. It is also possible to perform the aforementioned surface treatment on this substrate. It is preferable that the thickness of the substrate 6 be thin as long as the necessary functions are not hindered. Although it varies depending on the material, it is usually 1 μm to 10 mm, preferably 5 μm to 5 mm. Also, if necessary, the substrate can be made to function as an electrode.

(Formation of gate electrode)
A gate electrode 5 is formed on the substrate 6 (see FIG. 2(2)). As the electrode material, those described above are used. Various methods can be used as the method for forming the electrode film, and for example, a vacuum vapor deposition method, a sputtering method, a coating method, a thermal transfer method, a printing method, a sol-gel method, and the like are employed. During or after film formation, it is preferable to perform patterning as necessary so as to obtain a desired shape. As a patterning method, various methods can be used, and examples thereof include a photolithography method combining patterning of a photoresist and etching. In addition, printing methods such as vapor deposition using a shadow mask, sputtering, inkjet printing, screen printing, offset printing, letterpress printing, etc., soft lithography methods such as microcontact printing, and methods that combine these methods are used. and patterning is also possible. The film thickness of the gate electrode 5 varies depending on the material, but is usually 0.1 nm to 10 μm, preferably 0.5 nm to 5 μm, more preferably 1 nm to 3 μm. In addition, in the case of serving as both a gate electrode and a substrate, the film thickness may be larger than the above.

(Regarding the formation of the insulator layer)
An insulator layer 4 is formed on the gate electrode 5 (see FIG. 5(3)). As the insulator material, the materials described above are used. Various methods can be used to form the insulator layer 4 . For example, coating methods such as spin coating, spray coating, dip coating, casting, bar coating, and blade coating, printing methods such as screen printing, offset printing, and inkjet, vacuum deposition, molecular beam epitaxial growth, ion cluster beam, and ion spray. Dry process methods such as a coating method, a sputtering method, an atmospheric pressure plasma method, and a CVD method can be used. In addition, a sol-gel method, a method of forming an oxide film on a metal such as alumite on aluminum and silicon oxide on silicon by thermal oxidation or the like is adopted. In the portion where the insulator layer and the semiconductor layer are in contact with each other, the insulator layer may be subjected to a predetermined surface treatment in order to favorably orient the molecules of the compound that constitutes the semiconductor at the interface between the two layers. A surface treatment method similar to the surface treatment of the substrate can be used. The film thickness of the insulator layer 4 is preferably as thin as possible because the amount of electricity to be taken out can be increased by increasing the electric capacity. At this time, if the film is thin, the leakage current increases, so it is preferable that the film is thin as long as the function is not impaired. It is usually 0.1 nm to 100 μm, preferably 0.5 nm to 50 μm, more preferably 5 nm to 10 μm.

(Formation of organic thin film)
Various methods such as coating and printing can be used to form the organic thin film (organic semiconductor layer). Specifically, coating methods such as dip coating, die coater, roll coater, bar coater, and spin coat, ink jet, screen printing, offset printing, microcontact printing, and other solution process forming methods. is mentioned.

A method of forming an organic thin film by a solution process will be described. An organic semiconductor composition is applied to a substrate (insulator layer, exposed portions of source and drain electrodes). Application methods include spin coating, drop casting, dip coating, spraying, flexographic printing, letterpress printing such as resin letterpress printing, offset printing, dry offset printing, and lithographic printing such as pad printing. , intaglio printing methods such as gravure printing methods, silk screen printing methods, mimeograph printing methods, stencil printing methods such as ring graph printing methods, inkjet printing methods, microcontact printing methods, etc., and methods combining a plurality of these methods. be done.

Furthermore, as a method similar to the coating method, a Langmuir project method in which a monomolecular film of an organic thin film prepared by dropping the above composition on the surface of water is transferred to a substrate and laminated, and a liquid crystal or a melted material is applied to two sheets. It is also possible to adopt a method of sandwiching between substrates and introducing it between the substrates by capillarity.

The environment such as the temperature of the substrate and the composition during film formation is also important, and the characteristics of the transistor may change depending on the temperature of the substrate and the composition. Therefore, it is preferable to carefully select the temperature of the substrate and the composition. The substrate temperature is usually 0 to 200°C, preferably 10 to 120°C, more preferably 15 to 100°C. Care must be taken because it depends greatly on the solvent and the like in the composition used.

The film thickness of the organic thin film produced by this method is preferably as thin as possible without impairing the function. As the film thickness increases, there is a concern that leakage current will increase. The film thickness of the organic thin film is usually 1 nm to 1 μm, preferably 5 nm to 500 nm, more preferably 10 nm to 300 nm.

The properties of the organic thin film thus formed (see FIG. 5(4)) can be further improved by post-treatment. For example, heat treatment relaxes the strain in the film that occurred during film formation, reduces pinholes, etc., and can control the arrangement and orientation in the film. can be improved. When fabricating the organic transistor of the present invention, it is effective to perform this heat treatment in order to improve the characteristics. The heat treatment is performed by heating the substrate after forming the organic thin film. Although the temperature of the heat treatment is not particularly limited, it is usually room temperature to about 180°C, preferably 40 to 160°C, more preferably 45 to 150°C. The heat treatment time at this time is not particularly limited, but it is usually 10 seconds to 24 hours, preferably 30 seconds to 3 hours. The atmosphere at that time may be the air, or may be an inert atmosphere such as nitrogen or argon. In addition, it is possible to control the film shape by solvent vapor.

In addition, as another post-treatment method for organic thin films, a property change is induced by oxidation or reduction by treating with an oxidizing or reducing gas such as oxygen or hydrogen, or an oxidizing or reducing liquid. can also This can be used, for example, to increase or decrease the carrier density in the film.

Also, in a method called doping, the properties of an organic thin film can be changed by adding a trace amount of element, atomic group, molecule, or polymer to the organic thin film. For example, acids such as oxygen, hydrogen, hydrochloric acid, sulfuric acid, and sulfonic acid; Lewis acids such as PF ₅ , AsF ₅ and FeCl ₃ ; halogen atoms such as iodine; metal atoms such as sodium and potassium; It can be doped with donor compounds such as phthalocyanines. This can be achieved by contacting the organic thin film with these gases, immersing it in a solution, or electrochemically doping it. These dopings can be added at the time of synthesis of the organic semiconductor compound, added to the organic semiconductor composition, or added in the process of forming the organic thin film, even if it is not after the preparation of the organic thin film. In addition, the material used for doping is added to the material forming the organic thin film during vapor deposition and co-deposited, or it is mixed in the surrounding atmosphere during the preparation of the organic thin film (the organic thin film is formed in an environment where the doping material is present). It is also possible to dope the film by accelerating ions in vacuum and bombarding the film.

These doping effects include a change in electrical conductivity due to an increase or decrease in carrier density, a change in carrier polarity (p-type, n-type), a change in the Fermi level, and the like.

(Formation of source electrode and drain electrode)
The method of forming the source electrode 1 and the drain electrode 3 can be formed according to the case of the gate electrode 5 (see FIG. 5(5)). Various additives can be used to reduce the contact resistance with the organic thin film.

(About protective layer)
Forming the protective layer 7 on the organic thin film has the advantage of minimizing the influence of outside air and stabilizing the electrical characteristics of the organic transistor (see FIG. 5(6)). As the material for the protective layer, those mentioned above are used. Any film thickness of the protective layer 7 can be adopted depending on the purpose, but it is usually 100 nm to 1 mm.

Various methods can be used to form the protective layer. When the protective layer is made of resin, for example, a resin solution is applied and then dried to form a resin film; a resin monomer is applied or vapor deposited. a method of polymerizing later; and the like. A cross-linking treatment may be performed after film formation. When the protective layer is made of an inorganic material, for example, a forming method using a vacuum process such as a sputtering method or a vapor deposition method, or a forming method using a solution process such as a sol-gel method can be used.

In the organic thin film transistor, a protective layer can be provided not only on the organic thin film but also between each layer, if necessary. These layers may help stabilize the electrical properties of the organic transistor.

Since the organic semiconductor compound is used as the organic semiconductor composition, the organic thin film transistor can be produced by a relatively low-temperature process. Therefore, flexible materials such as plastic plates and plastic films, which cannot be used under high temperature conditions, can also be used as substrates. As a result, it becomes possible to manufacture a lightweight, flexible, and hard-to-break device, which can be used as a switching device for an active matrix of a display.

Organic thin film transistors can also be used as digital devices and analog devices such as memory circuit devices, signal driver circuit devices, and signal processing circuit devices. Furthermore, by combining these, it becomes possible to manufacture displays, IC cards, IC tags, and the like. Furthermore, organic transistors can be used as sensors because their characteristics can be changed by external stimuli such as chemical substances.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these.
In the present examples and comparative examples, OSC-1(9-octyl-3-phenylnaphtho[2′,3′:4,5] represented by the following formulas (1), (2), and (3) thieno[3,2-b][1]benzothiophene), OSC-2 (6,13-bis(triisopropylsilylethynyl)pentacene), and OSC-3 (2,7-dioctyl[1]benzothieno[3, 2-b][1]benzothiophene) was used as the organic semiconductor compound.

Reference Example 1 (Evaluation of solubility of organic semiconductor compound and insulating compound)
Solvents shown in Tables 1 to 8 below are added to about 1 mg of powder of organic semiconductor compounds (OSC-1, OSC-2, OSC-3), and the solubility (weight of organic semiconductor compound / total amount of organic semiconductor compound is dissolved) The weight of each solution required for the measurement × 100) was calculated. In addition, ascertainment of the point of complete dissolution was performed by visual confirmation. The results are shown in Tables 9-16. Polymethyl methacrylate (PMMA, molecular weight 120,000), poly(1-vinylnaphthalene) (P1VN, molecular weight 100,000), polystyrene (PS, molecular weight 1,000,000 or 280, 000) and poly-α-methylstyrene (PaMS, molecular weight 7,000) were also evaluated for solubility in the same manner, and the results are shown in Tables 9 to 16.
Mesitylene and cyclohexylbenzene in Table 11 are polystyrene with a molecular weight of 280,000, m-diethylbenzene and 1-chloronaphthalene in Table 11, and Tables 12, 13 and 16 are polystyrene with a molecular weight of 1,000,000. Solubility evaluated.

Reference Example 2 (Measurement of contact angle and sliding angle with respect to insulating compound layer)
On the insulating compound layer 1 made of polyvinylphenol (molecular weight: 25,000) or on the insulating compound layer 2 made of cycloolefin copolymer resin provided on the glass substrate, an insulating compound A solution or an insulating layer was applied. A compound B solution was dropped and the static contact angle was measured. Furthermore, the dynamic contact angle was measured by tilting the table on which the substrate was placed by 1°. The angle at which the droplet moved back and forth by 10 dots or more was defined as the sliding angle. Also, the insulating compound B solution was filtered and then measured. A contact angle meter DM-501 manufactured by Kyowa Interface Science Co., Ltd. was used to measure the contact angle. The results are shown in Tables 17-20.
Table 20 shows the measurement results of the contact angle using polystyrene with a molecular weight of 1,000,000 as the insulating compound.

Reference Example 3 (Measurement of contact angle and sliding angle for metal surface modified with self-assembled monolayer)
In place of the glass substrate provided with the insulating compound layer, the contact angle was measured according to Reference Example 2, except that a glass substrate was used in which the deposited silver thin film layer was surface-treated with a self-assembled monolayer (SAM). was measured. The results are shown in Tables 21-24.
PFBT in Tables 21 to 24 represents pentafluorobenzenethiol, 24FBT represents 2,4-difluorobenzenethiol, and CF34F represents 2,3,5,6-tetrafluoro-4-(trifluoromethyl)benzenethiol. . The surface treatment with the self-assembled monolayer was performed in the same manner as the SAM treatment described in Example 2.
Table 23 shows the measurement results of the contact angle using polystyrene with a molecular weight of 1,000,000 as the insulating compound.

Example 1 (Preparation of Organic Semiconductor Composition 1 of the Present Invention)
A solution obtained by mixing anisole as the organic solvent A and cyclohexylbenzene as the organic solvent B at a ratio of 8:2 was added with OSC-1 (organic semiconductor compound) and PMMA (insulating) in amounts of 0.3 wt% and 0.06 wt%. compound) was added and dissolved to prepare an organic semiconductor composition 1. The value of condition (1) calculated from the sliding angle in these combinations was 40°, the value of condition (2) was 37°, and the value of condition (3) was 3°.

Example 2 (Preparation of the organic thin film transistor element of the present invention)
A polyethylene glycol monomethyl ether acetate solution of polyvinylphenol (molecular weight: 25,000) was applied onto the washed glass substrate by spin coating and heated to form an insulating compound layer 1 . Ag was vacuum-deposited on the insulating compound layer 1 obtained above using a shadow mask to form a source electrode and a drain electrode each having a channel length of 20 μm and a channel width of 100 μm, thereby obtaining an electrode substrate. Next, the electrode substrate was treated with 10 mM pentafluorobenzenethiol (manufactured by Tokyo Kasei Co., Ltd.) (SAM treatment), and then the organic semiconductor composition 1 obtained in Example 1 was applied onto the substrate by spin coating. Then, the organic solvent was dried using a hot plate at 140° C. for 10 minutes to form an organic thin film layer (organic semiconductor layer). Next, a Teflon solution (FC43 solution of Teflon AF 1600X) was applied on the organic thin film layer by spin coating to form a gate insulating film layer. Finally, after setting the substrate with the gate edge film obtained above on a substrate holder to which a gate electrode mask was attached, Au was deposited using a vacuum deposition machine to obtain a top-gate-bottom-contact type organic thin-film transistor element of the present invention. 1 (FIG. 1F) was produced.

(Characteristic evaluation of organic thin film transistor element 1)
The performance of an organic transistor element depends on the amount of current that flows when a potential is applied between the source electrode and the drain electrode while a potential is applied to the gate. The mobility can be calculated by using the measurement result of the current value in the following formula (a) expressing the electrical characteristics of the carrier species generated in the organic thin film.
Id=ZμCi(VG−Vth−VD/2)VD/L (a)
In formula (a), Id is the source/drain current value, Z is the channel width, Ci is the capacitance of the insulator, VG is the gate potential, Vth is the threshold potential, L is the channel length, and micro is the mobility to be determined. (cm ² /Vs).
Eight or more organic thin film transistor elements 1 were produced on one substrate according to Example 2, and the drain voltage was swept from +30 V to -40 V under the condition of drain voltage -1 V. Results of measurement of change in drain current. The hole mobility calculated from the formula (a) was 1.93 cm ² /Vs, and the mobility variation was 22.8%.
As described above, the organic thin film transistor device 1 obtained using the organic semiconductor composition of the present invention was an excellent organic thin film transistor with high mobility and small variation in mobility.

Example 3 (Preparation of Organic Semiconductor Composition 2 of the Present Invention)
Organic semiconductor composition 2 was prepared according to Example 1, except that organic solvent B was changed from cyclohexylbenzene to cyclohexanol. Table 25 shows the type and concentration of the organic semiconductor compound in the organic semiconductor compositions 1 and 2, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A, the type and boiling point of the organic solvent B, the organic solvent A and the organic solvent B and the values of conditions (1) to (3) calculated from the sliding angles in these combinations.

Example 4 (Preparation and Characterization of Organic Thin Film Transistor Device 2 of the Present Invention)
The organic thin film transistor element 2 of the present invention was produced according to Example 2 except that the organic semiconductor composition 1 was changed to the organic semiconductor composition 2 obtained in Example 3, and the same evaluation of the characteristics of the organic thin film transistor element 1 was performed. The semiconductor characteristics were evaluated under the conditions of Table 26 shows the evaluation results of the characteristics of the organic thin film transistor elements 1 and 2.

Example 5 (Preparation of Organic Semiconductor Composition 3 of the Present Invention)
An organic semiconductor composition 3 was prepared according to Example 1, except that the organic solvent A was changed from anisole to phenetole, and the organic solvent B was changed from cyclohexylbenzene to bicyclohexyl.

Example 6 (Preparation and Characterization of Organic Thin Film Transistor Device 3 of the Present Invention)
The organic thin film transistor element 3 of the present invention was produced according to Example 2 except that the organic semiconductor composition 1 was changed to the organic semiconductor composition 3 obtained in Example 5, and the evaluation of the characteristics of the organic thin film transistor element 1 was the same. The semiconductor characteristics were evaluated under the conditions of

Examples 7 and 8 (Preparation of Organic Semiconductor Compositions 4 and 5 of the Invention)
Organic semiconductor compositions 4 and 5 were prepared according to Example 5, except that organic solvent B was changed from bicyclohexyl to decalin or cyclohexanol. Table 27 shows the type and concentration of the organic semiconductor in the organic semiconductor compositions 3 to 5, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A, the type and boiling point of the organic solvent B, the organic solvent A and the organic solvent B The values of conditions (1) to (3) calculated from the ratio and the sliding angle in combination thereof are shown.

Examples 9 and 10 (Preparation and Characterization of Organic Thin Film Transistor Elements 4 and 5 of the Present Invention)
Organic thin film transistor elements 4 and 5 of the present invention were produced according to Example 2 except that the organic semiconductor composition 1 was changed to the organic semiconductor compositions 4 and 5 obtained in Examples 7 and 8, and the organic thin film transistor elements The semiconductor characteristics were evaluated under the same conditions as the characteristics evaluation of 1. Table 28 shows the evaluation results of the characteristics of the organic thin film transistor elements 3 to 5.

Examples 11 and 12 (Preparation of Organic Semiconductor Compositions 6 and 7 of the Invention)
Organic semiconductor compositions 6 and 7 were prepared according to Example 5, except that organic solvent B was changed from bicyclohexyl to 1-decene or isophorone. Table 29 shows the type and concentration of the organic semiconductor in the organic semiconductor compositions 6 and 7, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A, the type and boiling point of the organic solvent B, the organic solvent A and the organic solvent B The values of conditions (1) to (3) calculated from the ratio and the sliding angle in combination thereof are shown.

Examples 13 and 14 (Preparation and Characterization of Organic Thin Film Transistor Elements 6 and 7 of the Present Invention)
Example 2 except that the insulating compound layer 1 was changed to the insulating compound layer 2 which is a cycloolefin resin, and the organic semiconductor composition 1 was changed to the organic semiconductor compositions 6 and 7 obtained in Examples 11 and 12, respectively. The organic thin film transistor elements 6 and 7 of the present invention were produced according to , and the semiconductor characteristics were evaluated under the same conditions as the evaluation of the characteristics of the organic thin film transistor element 1 . Table 30 shows the evaluation results of the characteristics of the organic thin film transistor elements 6 and 7.

Example 15 (Preparation of Organic Semiconductor Composition 8 of the Present Invention)
To a solution obtained by mixing o-xylene as organic solvent A and bicyclohexyl as organic solvent B at a ratio of 9:1, OSC-1 (organic semiconductor compound) and P1VN ( Insulating compound) was added and dissolved to prepare an organic semiconductor composition 8. The value of condition (1) calculated from the sliding angle in these combinations was 18°, the value of condition (2) was 40°, and the value of condition (3) was 22°. Table 31 shows the type and concentration of the organic semiconductor, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A in the organic semiconductor composition 16, the type and boiling point of the organic solvent B, the ratio of the organic solvent A and the organic solvent B, and the values of conditions (1) to (3) calculated from the sliding angles in these combinations.

Example 16 (Preparation and Characterization of Organic Thin Film Transistor Device 8 of the Present Invention)
The organic thin film transistor element 8 of the present invention was produced according to Example 2 except that the organic semiconductor composition 1 was changed to the organic semiconductor composition 8 obtained in Example 15, and the same evaluation of the characteristics of the organic thin film transistor element 1 was performed. The semiconductor characteristics were evaluated under the conditions of Table 32 shows the evaluation results of the characteristics of the organic thin film transistor element 8.

Example 17 (Preparation of Organic Semiconductor Composition 9 of the Present Invention)
An organic semiconductor composition 9 was prepared according to Example 15 except that the organic solvent A was changed from o-xylene to mesitylene and the organic solvent B was changed from bicyclohexyl to cyclohexanol. Table 33 shows the type and concentration of the organic semiconductor in the organic semiconductor composition 17, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A, the boiling point difference between the organic solvent A and the organic solvent B, the organic solvent A and the organic solvent B and the values of conditions (1) to (3) calculated from the sliding angles in these combinations.

Example 18 (Preparation and Characterization of Organic Thin Film Transistor Device 9 of the Present Invention)
An organic thin film transistor element 9 of the present invention was produced according to Example 2 except that the organic semiconductor composition 1 was changed to the organic semiconductor composition 9 obtained in Example 17, and the same evaluation of the characteristics of the organic thin film transistor element 1 was performed. The semiconductor characteristics were evaluated under the conditions of Table 34 shows the evaluation results of the characteristics of the organic thin film transistor element 9.

As described above, the organic thin film transistor device obtained using the organic semiconductor composition of the present invention was an excellent transistor device with high mobility and small variation in mobility.

Comparative Example 1 (Preparation of organic semiconductor composition 10 for comparison)
An organic semiconductor composition 10 for comparison was prepared according to Example 17 except that the organic solvent B was changed from cyclohexanol to hexadecane. The value of condition (1) calculated from the sliding angle in these combinations was 18°, the value of condition (2) was 19°, and the value of condition (3) was 1°. Table 35 shows the type and concentration of the organic semiconductor, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A in the organic semiconductor composition 12, the type and boiling point of the organic solvent B, the ratio of the organic solvent A and the organic solvent B, and the values of conditions (1) to (3) calculated from the sliding angles in these combinations.

Comparative Example 2 (Preparation and characteristic evaluation of organic thin film transistor element 10 for comparison)
An organic thin film transistor element 10 for comparison was prepared according to Example 2 except that the organic semiconductor composition 1 was changed to the organic semiconductor composition 10 obtained in Comparative Example 1, and the evaluation of the characteristics of the organic thin film transistor element 1 was the same. The semiconductor characteristics were evaluated under the conditions of Table 36 shows the evaluation results of the characteristics of the organic thin film transistor element 12.

From the above, when the characteristics of the organic transistor element 10 produced using the organic semiconductor composition 10 for comparison were evaluated, the variation in mobility became large. From this, it was found that when the condition (3) exceeding 1 is not satisfied, the variation becomes large.

Comparative Example 3 (Preparation of organic semiconductor composition 11 for comparison)
A solution obtained by mixing anisole as the organic solvent A and tetralin as the organic solvent B at a ratio of 8:2 was added with OSC-1 (organic semiconductor compound) and P1VN (insulating compound) in amounts of 0.3 wt% and 0.06 wt%. ) was added and dissolved to prepare an organic semiconductor composition 11 for comparison. The value of condition (1) calculated from the sliding angle in these combinations was 0°, the value of condition (2) was 3°, and the value of condition (3) was 3°. According to Reference Example 1, anisole has a solubility of 0.4 wt % for OSC-1 and a solubility of 10 wt % or more for P1VN. Therefore, anisole is a good solvent for OSC-1 and P1VN. Similarly, tetralin is a good solvent for OSC-1 and P1VN because it has a solubility of 0.5 wt % for OSC-1 and 10 wt % or more for P1VN. Table 37 shows the type and boiling point of organic solvent A in organic semiconductor composition 11, the type and boiling point of organic solvent B, the ratio of organic solvent A and organic solvent B, and the conditions (1) to The value of (3) is shown.

Comparative Example 4 (Preparation and characteristic evaluation of organic thin film transistor element 11 for comparison)
The insulating layer 1 is the insulating layer 2 that is a cycloolefin resin, the SAM is from pentafluorobenzenethiol to 2,4-difluorobenzenethiol, and the organic semiconductor composition 1 is the organic semiconductor composition 11 obtained in Comparative Example 1. An organic thin film transistor element 11 for comparison was produced according to Example 2 except that each was changed, and the semiconductor characteristics were evaluated under the same conditions as the characteristic evaluation of the organic thin film transistor element 1. Table 38 shows the evaluation results of the characteristics of the organic thin film transistor element 11.

From the above, when the characteristics of the organic transistor element 11 produced using the organic semiconductor composition 11 for comparison were evaluated, the variation increased. From this, it was found that when the organic solvent B does not satisfy the condition that the organic solvent B is a poor solvent for the organic semiconductor and the insulating compound, the characteristics of the organic semiconductor device do not have high mobility and low variation.

Comparative Example 5 (Preparation of organic semiconductor composition 12 for comparison)
The organic solvent to be used is 0.57 wt% and 0.11 wt% in the solvent composition described in Patent Document 1, that is, a solution in which mesitylene as organic solvent A and cyclohexylbenzene as organic solvent B are mixed at a ratio of 2:8. Amounts of OSC-1 (organic semiconductor compound) and PS (insulating compound) were added and dissolved to prepare organic semiconductor composition 12 for comparison. The value of condition (1) calculated from the sliding angle in these combinations was 8°, the value of condition (2) was 39°, and the value of condition (3) was 31°. According to Reference Example 1, mesitylene has a solubility of 0.3 wt % for OSC-1 and a solubility of 5 wt % for PS, so it is a good solvent for OSC-1 and PS. Similarly, OSC-1 and cyclohexylbenzene are poor solvents for OSC-1 and good solvents for PS, since the solubility of OSC-1 is 0.1% or less and the solubility of P1VN is 10% or more. Table 39 shows the type and concentration of the organic semiconductor in the organic semiconductor composition 12, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A, the type and boiling point of the organic solvent B, the ratio of the organic solvent A and the organic solvent B, and the values of conditions (1) to (3) calculated from the sliding angles in these combinations.
Table 39 shows the measurement results of the contact angle using polystyrene with a molecular weight of 1,000,000 as the insulating compound.

Comparative Example 6 (Preparation and characteristic evaluation of organic thin film transistor element 14 for comparison)
An organic thin film transistor element 12 for comparison was prepared according to Example 2 except that the organic semiconductor composition 1 was changed to the organic semiconductor composition 12 obtained in Comparative Example 5, and the evaluation of the characteristics of the organic thin film transistor element 1 was the same. The semiconductor characteristics were evaluated under the conditions of Table 40 shows the evaluation results of the characteristics of the organic thin film transistor element 12.

From the above, when the characteristics of the organic transistor element 12 produced using the organic semiconductor composition 12 for comparison were evaluated, the average mobility was small. From this, it was found that when the condition that the organic solvent B is a poor solvent for the organic semiconductor and the insulating compound is not satisfied, the variation in the specific mobility of the organic semiconductor device becomes large.

Comparative Examples 7 and 8 (Preparation of Comparative Organic Semiconductor Compositions 13 and 14)
Comparative organic semiconductor compositions 13 and 14 were prepared according to Comparative Example 5 except that the organic semiconductor compound used was changed from OSC-1 to OSC-2 and OSC-3. According to Reference Example 1, cyclohexylbenzene has a solubility of 1% or more for OSC-2 and OSC-3 and a solubility of 10% or more for PS, and thus is a good solvent for OSC-1, OSC-3, and PS. Table 41 shows the type and concentration of the organic semiconductor in the organic semiconductor compositions 13 and 14, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A, the type and boiling point of the organic solvent B, the organic solvent A and the organic solvent B The values of conditions (1) to (3) calculated from the ratio and the sliding angle in combination thereof are shown.
Table 41 shows the measurement results of the contact angle using polystyrene with a molecular weight of 1,000,000 as the insulating compound.

Comparative Examples 9 and 10 (Preparation and property evaluation of organic thin film transistor elements 13 and 14 for comparison)
Organic thin film transistor elements 13 and 14 for comparison were produced according to Example 2 except that organic semiconductor composition 1 was changed to organic semiconductor compositions 13 and 14 obtained in Comparative Examples 7 and 8, and organic thin film transistor elements The semiconductor characteristics were evaluated under the same conditions as the characteristics evaluation of 1. Table 42 shows the evaluation results of the characteristics of the organic thin film transistor elements 13 and 14.

From the above, when the characteristics of the organic transistor elements 13 to 14 produced using the organic semiconductor compositions 13 to 14 for comparison are evaluated, both the average mobility and the maximum mobility are small, and the mobility variation is large. became. From this, it was found that when the organic solvent B does not satisfy the condition that the organic solvent B is a poor solvent for the organic semiconductor and the insulating compound, the characteristics of the organic semiconductor device do not have high mobility and low variation.

Comparative Example 11 (Preparation of Comparative Organic Semiconductor Composition 15)
The organic solvent to be used is the solvent composition described in Patent Document 3, that is, a solution in which m-diethylbenzene as organic solvent A and 1-chloronaphthalene as organic solvent B are mixed at a ratio of 8:2, 0.2 wt % and 0.2 wt %. 1 wt % of OSC-1 (organic semiconductor compound) and PaMS (insulating compound) were added and dissolved to prepare organic semiconductor composition 15 for comparison. The value of condition (1) calculated from the sliding angle in these combinations was 17°, the value of condition (2) was 43°, and the value of condition (3) was 26°. According to Reference Example 1, m-diethylbenzene has a solubility of OSC-1 of 0.1% or less and a solubility of PaMS of 10% or more. Therefore, m-diethylbenzene is a poor solvent for OSC-1 and a good solvent for PaMS. Similarly, 1-chloronaphthalene is a good solvent for OSC-1 and PaMS because it has a solubility of 0.1% for organic semiconductors and a solubility of 10% or more for PaMS. Table 43 shows the type and concentration of the organic semiconductor in the organic semiconductor composition 15, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A, the type and boiling point of the organic solvent B, the ratio of the organic solvent A and the organic solvent B, and the values of conditions (1) to (3) calculated from the sliding angles in these combinations.

Comparative Example 12 (Preparation and characteristic evaluation of organic thin film transistor element 15 for comparison)
An organic thin film transistor element 15 for comparison was prepared according to Example 2, except that the organic semiconductor composition 1 was changed to the organic semiconductor composition 15 obtained in Comparative Example 11, and the evaluation of the characteristics of the organic thin film transistor element 1 was the same. The semiconductor characteristics were evaluated under the conditions of Table 44 shows the evaluation results of the characteristics of the organic thin film transistor device 15.

From the above, when the characteristics of the organic transistor element 15 produced using the organic semiconductor composition 15 for comparison were evaluated, both the average mobility and the maximum mobility were small. From this, it was found that when the organic solvent B does not satisfy the condition that the organic solvent B is a poor solvent for the organic semiconductor and the insulating compound, the characteristics of the organic semiconductor device do not have high mobility and low variation.

Comparative Example 13 (Preparation of Comparative Organic Semiconductor Composition 16)
An organic semiconductor composition 16 for comparison was prepared according to Comparative Example 11 except that the organic semiconductor used was changed from OSC-1 to OSC-3. According to Reference Example 1, m-diethylbenzene has a solubility of 1 wt % or more for OSC-3 and a solubility of 10 wt % or more for PaMS, and is therefore a good solvent for OSC-3 and PaMS. 1-Chloronaphthalene is a good solvent for OSC-3 and PaMS because the solubility of OSC-3 is 1 wt % or more and the solubility of PaMS is 10 wt % or more. Table 45 shows the type and concentration of the organic semiconductor in the organic semiconductor composition 16, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A, the type and boiling point of the organic solvent B, the ratio of the organic solvent A and the organic solvent B, and the values of conditions (1) to (3) calculated from the sliding angles in these combinations.

Comparative Example 14 (Preparation of organic thin film transistor element for comparison)
An attempt was made to produce a comparative organic thin film transistor element according to Example 2, except that the organic semiconductor composition 1 was changed to the organic semiconductor composition 16 obtained in Comparative Example 13. It was not possible to form a film on it. Therefore, the semiconductor characteristics were not evaluated.

From the above, an attempt was made to produce an organic transistor element produced using the organic semiconductor composition 16 for comparison, but an organic thin film could not be formed by the spin coating method. From this, it was found that the organic semiconductor element could not be produced in some cases when the condition that the organic solvent B is a poor solvent for the organic semiconductor and the insulating compound is not satisfied.

Comparative Example 15 (Preparation of Comparative Organic Semiconductor Composition 17)
An organic semiconductor composition 17 for comparison was prepared according to Comparative Example 11 except that the insulating compound used was changed from PaMS to PS. According to Reference Example 1, m-diethylbenzene has a solubility of OSC-1 of 0.1% or less and a solubility of PS of 10% or more. Therefore, m-diethylbenzene is a poor solvent for OSC-1 and a good solvent for PaMS. Since 1-chloronaphthalene has a solubility of 0.1% for OSC-1 and a solubility of 10% or more for PaMS, it is a good solvent for OSC-1 and PaMS. Table 46 shows the type and concentration of the organic semiconductor in the organic semiconductor composition 17, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A, the type and boiling point of the organic solvent B, the ratio of the organic solvent A and the organic solvent B, and the values of conditions (1) to (3) calculated from the sliding angles in these combinations.
Table 46 shows the measurement results of the contact angle using polystyrene with a molecular weight of 1,000,000 as the insulating compound.

Comparative Example 16 (Preparation and characteristic evaluation of organic thin film transistor element 17 for comparison)
An organic thin film transistor element 17 for comparison was prepared according to Example 2 except that the organic semiconductor composition 1 was changed to the organic semiconductor composition 17 obtained in Comparative Example 15, and the evaluation of the characteristics of the organic thin film transistor element 1 was the same. The semiconductor characteristics were evaluated under the conditions of Table 47 shows the evaluation results of the characteristics of the organic thin film transistor element 17.

As described above, when the characteristics of the organic transistor element 17 produced using the organic semiconductor composition 17 for comparison were evaluated, both the average mobility and the maximum mobility were small, and the variation was large. From this, it was found that when the organic solvent B does not satisfy the condition that the organic solvent B is a poor solvent for the organic semiconductor and the insulating compound, the characteristics of the organic semiconductor device do not have high mobility and low variation.

Comparative Example 17 (Preparation of Comparative Organic Semiconductor Composition 18)
An organic semiconductor composition 18 for comparison was prepared according to Comparative Example 13 except that the insulating compound used was changed from PaMS to PS. According to Reference Example 1, m-diethylbenzene has a solubility of 1% or more for OSC-3 and a solubility of 10% or more for PS, and thus is a good solvent for OSC-3 and PS. 1-Chloronaphthalene is a good solvent for OSC-3 and PaMS because the solubility of OSC-3 is 1% or more and the solubility of PS is 10% or more. Table 48 shows the type and concentration of the organic semiconductor in the organic semiconductor composition 18, the type and concentration of the insulating compound, the type and boiling point of the organic solvent A, the type and boiling point of the organic solvent B, and the boiling point difference between the organic solvent A and organic solvent B. , the ratio of the organic solvent A and the organic solvent B, and the values of the conditions (1) to (3) calculated from the sliding angle in the combination thereof.

Comparative Example 18 (Preparation of organic thin film transistor element for comparison)
An attempt was made to produce a comparative organic thin film transistor element according to Example 2, except that the organic semiconductor composition 1 was changed to the organic semiconductor composition 18 obtained in Comparative Example 17. It was not possible to form a film on it. Therefore, the semiconductor characteristics were not evaluated.

From the above, an attempt was made to produce an organic transistor element produced using the organic semiconductor composition 18 for comparison, but an organic thin film could not be formed by the spin coating method. From this, it was found that the organic semiconductor element could not be produced in some cases when the condition that the organic solvent B is a poor solvent for the organic semiconductor and the insulating compound is not satisfied.

By using the organic semiconductor composition of the present invention, a practical organic thin film transistor with high mobility and small variation in mobility can be obtained.

1 source electrode 2 organic thin film (organic semiconductor layer)
3 drain electrode 4 insulator layer 5 gate electrode 6 substrate 7 protective layer

Claims (12)

An electrode substrate having a substrate, an insulating compound layer made of an insulating compound provided on the substrate, and an electrode made of a metal thin film layer provided on the insulating compound layer; and an organic compound provided on the electrode substrate. An organic semiconductor composition for forming an organic thin film of an organic thin film transistor element having an organic thin film layer containing a semiconductor compound,
The organic semiconductor compound is the following formula (1) or (2)

(In formula (1), R ₁ and R ₂ independently represent an aliphatic hydrocarbon group having 1 to 36 carbon atoms. In formula (2), either one of R ₃ and R ₄ is an alkyl group, an alkyl one represents an aromatic hydrocarbon _{group having} an alkyl except when it is a base.)
is a compound represented by
Containing an organic semiconductor compound, an insulating compound, an organic solvent A that is a good solvent for the organic semiconductor compound and the insulating compound, and an organic solvent B that is a poor solvent for the organic semiconductor compound and the insulating compound,
In addition, the sliding angle of the organic solvent A solution having an insulating compound concentration of 1% by weight or more with respect to the insulating compound layer and the metal thin film layer is θ _{SUB (A')} (°) and θ _{METAL (A')} (°), and the insulating property When the sliding angles of the saturated organic solvent B solution of the compound with respect to the insulating compound layer and the metal thin film layer are θ _{SUB (B')} (°) and θ _{METAL (B')} (°), the following conditions (1) to (3)
Condition (1);
1°≦|θ _METAL(A′) −θ _SUB(A′) |
Condition (2):
1°≦|θ _METAL(B′) −θ _SUB(B′) |
Condition (3):
1°<||θ _METAL(A′) −θ _SUB(A′) |−|θ _METAL(B′) −θ _SUB(B′) ||
An organic semiconductor composition that satisfies all the relationships of 2. The organic semiconductor composition according to claim 1, wherein the organic semiconductor compound is a compound represented by formula (2). Condition (3) is 1°<||θ _METAL(A′) −θ _SUB(A′) |−|θ _METAL(B′) −θ _SUB(B′) ||<35°
The organic semiconductor composition according to claim 1. Condition (1) is 1°≦|θ _METAL(A′) −θ _SUB(A′) |≦20°
and
and condition (2) is 1°≦|θ _METAL(B′) −θ _SUB(B′) |≦40°
The organic semiconductor composition according to claim 3 . Condition (1) is 20°≦|θ _METAL(A′) −θ _SUB(A′) |≦40°
and
and condition (2) is 1°≦|θ _METAL(B′) −θ _SUB(B′) |≦40°
The organic semiconductor composition according to claim 3 . The organic semiconductor composition according to any one of claims 1 to 5, wherein the boiling point difference between the organic solvent A and the organic solvent B is 20°C or higher and 100°C or lower. 7. The organic semiconductor composition according to any one of claims 1 to 6, wherein the organic solvent A or organic solvent B is a compound having cycloalkane as a substituent. 8. The organic semiconductor composition according to any one of claims 1 to 7, wherein the content of the organic solvent B is 10% by weight or more. 9. The organic semiconductor compound according to any one of claims 1 to 8, wherein the solubility of the organic semiconductor compound in the organic solvent A is 0.1% by weight or more, and the solubility of the organic semiconductor compound in the organic solvent B is less than 0.1% by weight. organic semiconductor composition. 10. The organic compound according to any one of claims 1 to 9, wherein the solubility of the insulating compound in the organic solvent A is 1% by weight or more and the solubility of the insulating compound in the organic solvent B is less than 0.1% by weight. semiconductor composition. An organic thin film obtained by coating and drying the organic semiconductor composition according to any one of claims 1 to 10 . An organic thin film transistor comprising the organic thin film according to claim 11 .

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