JP2016092179A - Organic transistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic transistor which has high mobility and a large current on/off ratio and is excellent in storage stability.SOLUTION: The organic transistor contains at least one compound selected from compounds represented by general formula (1) in an organic semiconductor layer. [In the formula, Xto Xeach independently represent a hydrogen atom, a 5-12 carbon number linear, branched or cyclic alkyl group, a 5-12 carbon number linear, branched or cyclic alkoxyalkyl group, or a 5-12 carbon number linear, branched or cyclic alkoxyalkoxy group (provided that Xto Xdo not simultaneously represent hydrogen atoms).]SELECTED DRAWING: None

Description

The present invention relates to an organic transistor. More specifically, the present invention relates to an organic transistor using a specific organic compound in an organic semiconductor layer.

  Conventionally, a thin film transistor (TFT) made of amorphous silicon or polycrystalline silicon has been widely used as a switching element for flat panel display such as a liquid crystal display device. However, a CVD apparatus used for manufacturing a thin film transistor using silicon is expensive, and manufacturing a large-sized thin film transistor element has a drawback of increasing manufacturing cost.

In addition, since amorphous silicon and polycrystalline silicon are formed at a high temperature, there is a problem that a plastic material that is lightweight and flexible but has poor heat resistance cannot be used as a substrate. .
In order to solve the above problem, an organic transistor (also referred to as an organic thin film transistor or an organic TFT) using an organic compound for a channel semiconductor layer (hereinafter referred to as an organic semiconductor layer) instead of amorphous silicon or polycrystalline silicon is proposed. (Non-Patent Document 1).

As a method for forming the organic semiconductor layer, for example, a vacuum deposition method or a coating method is known. According to these film formation methods, it is easy to increase the size of the organic transistor element while suppressing the manufacturing cost. .
Furthermore, the temperature required for film formation can be lowered, and organic transistors using organic compounds can use plastic materials for the substrate, which can be applied to flexible display elements. Expectations are gathered for the transformation.

A practical organic transistor needs to have characteristics such as high charge mobility and a large current on / off ratio. Here, the term “on / off ratio” means the ratio of the current between the source electrode and the drain electrode when the organic transistor is on to the current between the source electrode and the drain electrode when the organic transistor is off. To do.
Furthermore, excellent storage stability is required for practical application of organic transistors.

To date, organic transistors using, for example, pentacene as the organic semiconductor layer have been proposed (Non-Patent Document 2).
However, an organic transistor using pentacene has a problem that it has a low function as an organic transistor in the atmosphere and low storage stability.
Furthermore, an organic transistor using a thiophene oligomer (α-hexathienylene) as an organic semiconductor layer has been proposed (Non-patent Document 3). However, the organic transistor also has a drawback that its storage stability in air is low.

As a thiophene compound, for example, an organic transistor using a compound of the formula (A) in an organic semiconductor layer has been proposed (Non-Patent Document 4).

In addition, as a thiophene compound, for example, a compound of the formula (B) is produced, and application to an organic transistor is suggested (Non-patent Document 5).

Organic transistors using these compounds of formula (A) and formula (B) have a relatively high charge mobility and good storage stability, but currently have higher charge mobility. Is required.
In addition, the solubility of the compounds of formula (A) and formula (B) in an organic solvent is low, and there is a difficulty that an organic semiconductor layer cannot be formed by a wet process by dissolving in an organic solvent, and further improvement is required. Yes.

Appl.Phys.Lett., 63,1372 (1993) Appl.Phys.Lett., 72,1854 (1998) Science, 268,270 (1995) Organic Electronics, 13,3268 (2012) Tetrahedron Lett., 46,8153 (2005)

To date, organic transistors using various organic compounds as organic semiconductor layers have been proposed, but none of them has practically satisfactory characteristics. .
In view of the above, the present invention is to provide an organic transistor having a high charge mobility, a large current on / off ratio, excellent solubility in an organic solvent, and excellent storage stability.

〔式中、Ｘ_１〜Ｘ_４はそれぞれ独立に、水素原子、炭素数５〜１２の直鎖、分岐または環状のアルキル基、炭素数５〜１２の直鎖、分岐または環状のアルコキシアルキル基、或いは炭素数５〜１２の直鎖、分岐または環状のアルコキシアルコキシ基を表す(但し、Ｘ_１〜Ｘ_４は同時に水素原子を表すことはない）〕
As a result of intensive studies in order to solve the above problems, the inventor of the present invention is an organic transistor comprising at least one compound selected from compounds represented by the general formula (1) in an organic semiconductor layer. It has been found that it has a high degree of current, a large current on / off ratio, excellent solubility in organic solvents, and excellent storage stability, and the present invention has been completed.

That is, the present invention
An organic transistor having an organic semiconductor layer is an organic transistor comprising at least one compound selected from the compounds represented by the general formula (1) in the organic semiconductor layer.

[Wherein, X _{1 to} X ₄ each independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 5 to 12 carbon atoms, a linear, branched or cyclic alkoxyalkyl group having 5 to 12 carbon atoms, Alternatively, it represents a linear, branched or cyclic alkoxyalkoxy group having 5 to 12 carbon atoms (provided that X _{1 to} X ₄ do not represent hydrogen atoms at the same time).

According to the present invention, it is possible to provide an organic transistor having high charge mobility, a large current on / off ratio, excellent solubility in an organic solvent, and excellent storage stability.

It is typical sectional drawing of the organic transistor of this invention. It is typical sectional drawing of the organic transistor of this invention. It is typical sectional drawing of the organic transistor of this invention. It is typical sectional drawing of the organic transistor of this invention.

〔式中、Ｘ_１〜Ｘ_４はそれぞれ独立に、水素原子、炭素数５〜１２の直鎖、分岐または環状のアルキル基、炭素数５〜１２の直鎖、分岐または環状のアルコキシアルキル基、或いは炭素数５〜１２の直鎖、分岐または環状のアルコキシアルコキシ基を表す(但し、Ｘ_１〜Ｘ_４は同時に水素原子を表すことはない）〕 Hereinafter, the present invention will be described in detail.
The organic transistor of the present invention comprises an organic semiconductor layer containing at least one compound selected from the compounds represented by the general formula (1).

[Wherein, X _{1 to} X ₄ each independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 5 to 12 carbon atoms, a linear, branched or cyclic alkoxyalkyl group having 5 to 12 carbon atoms, Alternatively, it represents a linear, branched or cyclic alkoxyalkoxy group having 5 to 12 carbon atoms (provided that X _{1 to} X ₄ do not represent hydrogen atoms at the same time).

X _{1 to} X ₄ in the compound represented by the general formula (1) are each independently a hydrogen atom, a halogen atom, a linear, branched or cyclic alkyl group having 5 to 12 carbon atoms, and a straight chain having 5 to 12 carbon atoms. Represents a chain, branched or cyclic alkoxyalkyl group, or a linear, branched or cyclic alkoxyalkoxy group having 5 to 12 carbon atoms (provided that X _{1 to} X ₄ do not represent a hydrogen atom at the same time);

More preferably, among the substituents X _{1 to} X ₄ , at least one substituent is more preferable, and two substituents are preferably a linear, branched or cyclic alkyl group having 5 to 12 carbon atoms, carbon number 5 Represents a -12 linear, branched or cyclic alkoxyalkyl group, or a C5-12 linear, branched or cyclic alkoxyalkoxy group.

Specific examples of the substituents X _{1 to} X ₄ in the compound represented by the general formula (1) include, for example, a hydrogen atom; for example, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, n-hexyl. Group, 1-methylpentyl group, 4-methyl-2-pentyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, n-heptyl group, 1-methylhexyl group, cyclohexylmethyl group, n-octyl group, tert-octyl group, 1-methylheptyl group, 2-ethylhexyl group, 2-propylpentyl group, n-nonyl group, 2,2-dimethylheptyl group, 2,6-dimethyl-4-heptyl group, 3,5,5 5-trimethylhexyl group, n-decyl group, n-undecyl group, 1-methyldecyl group, n-dodecyl group, cyclopentyl group, cyclohexyl group, 4- Chill cyclohexyl group, 4-tert-butylcyclohexyl group, cycloheptyl group, straight-chain, branched or cyclic alkyl group having 5 to 12 carbon atoms such as cyclooctyl group;

For example, n-butoxymethyl group, n-pentyloxymethyl group, n-hexyloxymethyl group, (2-ethylbutyloxy) methyl group, n-heptyloxymethyl group, n-octyloxymethyl group, n-decyloxy Methyl group, 2-n-propoxyethyl group, 2-isopropoxyethyl group, 2-n-butoxyethyl group, 2-n-pentyloxyethyl group, 2-n-hexyloxyethyl group, 2- (2′- Ethylbutyloxy) ethyl group, 2-n-heptyloxyethyl group, 2-n-octyloxyethyl group, 2- (2′-ethylhexyloxy) ethyl group, 2-n-decyloxyethyl group, 2-cyclohexyloxy Ethyl group, 1-ethoxypropyl group, 2-ethoxypropyl group, 3-ethoxypropyl group, 3-n-propoxypropyl group, -Isopropoxypropyl group, 3-n-butoxypropyl group, 3-n-pentyloxypropyl group, 3-n-hexyloxypropyl group, 3- (2'-ethylbutoxy) propyl group, 3-n-octyloxy Propyl group, 3- (2′-ethylhexyloxy) propyl group, 3-cyclohexyloxypropyl group, 4-methoxybutyl group, 4-ethoxybutyl group, 4-n-propoxybutyl group, 4-isopropoxybutyl group, 4 -N-butoxybutyl group, 4-n-hexyloxybutyl group, 4-n-octyloxybutyl group, 5-methoxypentyl group, 5-ethoxypentyl group, 5-n-propoxypentyl group, 5-n-pentyl Oxypentyl group, 6-methoxyhexyl group, 6-ethoxyhexyl group, 6-isopropoxyhexyl group, 6- -Butoxyhexyl group, 6-n-hexyloxyhexyl group, 4-methoxycyclohexyl group, 7-methoxyheptyl group, 7-ethoxyheptyl group, 7-isopropoxyheptyl group, 8-methoxyoctyl group, 8-ethoxyoctyl group , 9-methoxynonyl group, 9-ethoxynonyl group, 10-methoxydecyl group, 10-ethoxydecyl group, 11-methoxyundecyl group, tetrahydrofurfuryl group, etc., linear, branched or cyclic having 5 to 12 carbon atoms An alkoxyalkyl group of

For example, n-butoxymethoxy group, n-pentyloxymethoxy group, n-hexyloxymethoxy group, (2-ethylbutoxy) methoxy group, n-heptyloxymethoxy group, n-octyloxymethoxy group, n-decyloxymethoxy Group, 2-n-propoxyethoxy group, 2-isopropoxyethoxy group, 2-n-butoxyethoxy group, 2-n-pentyloxyethoxy group, 2-n-hexyloxyethoxy group, 2- (2′-ethyl) Butyloxy) ethoxy group, 2-n-heptyloxyethoxy group, 2-n-octyloxyethoxy group, 2- (2′-ethylhexyloxy) ethoxy group, 2-n-decyloxyethoxy group, 2-cyclohexyloxyethoxy group Group, 1-ethoxypropoxy group, 2-ethoxypropoxy group, 3-ethoxypropoxy group Si group, 3-n-propoxypropoxy group, 3-isopropoxypropoxy group, 3-n-butoxypropoxy group, 3-n-pentyloxypropoxy group, 3-n-hexyloxypropoxy group, 3- (2′- Ethylbutoxy) propoxy group, 3-n-octyloxypropoxy group, 3- (2′-ethylhexyloxy) propoxy group, 3-cyclohexyloxypropoxy group, 2-methoxybutoxy group, 3-methoxybutoxy group, 4-methoxybutoxy group Group, 4-ethoxybutoxy group, 4-n-propoxybutoxy group, 4-isopropoxybutoxy group, 4-n-butoxybutoxy group, 4-n-hexyloxybutoxy group, 4-n-octyloxybutoxy group, 5 -Methoxypentyloxy group, 5-ethoxypentyloxy group, 5-n-propoxy Pentyloxy group, 5-n-pentyloxypentyloxy group, 6-methoxyhexyloxy group, 6-ethoxyhexyloxy group, 6-isopropoxyhexyloxy group, 6-n-butoxyhexyloxy group, 6-n-hexyl Oxyhexyloxy group, 4-methoxycyclohexyloxy group, 7-methoxyheptyloxy group, 7-ethoxyheptyloxy group, 7-isopropoxyheptyloxy group, 8-methoxyoctyloxy group, 8-ethoxyoctyloxy group, 9- Straight chain having 5 to 12 carbon atoms such as methoxynonyloxy group, 9-ethoxynonyloxy group, 10-methoxydecyloxy group, 10-ethoxydecyloxy group, 11-methoxyundecyloxy group, tetrahydrofurfuryloxy group, Branched or cyclic alkoxyalkoxy group Can be mentioned.

In the general formula (1), the substituents X _{1 to} X ₄ are each independently a hydrogen atom, a linear, branched or cyclic alkyl group having 5 to 12 carbon atoms, a linear or branched chain having 5 to 12 carbon atoms. Alternatively, a compound representing a cyclic alkoxyalkyl group or a linear, branched or cyclic alkoxyalkoxy group having 5 to 12 carbon atoms (provided that X _{1 to} X ₄ do not represent hydrogen atoms at the same time) is added to the organic semiconductor layer. The organic transistor used has high charge mobility.
The reason is not clear, but in the general formula (1), the substituents X _{1 to} X ₄ having 4 or less carbon atoms are straight, branched or cyclic alkyl groups, linear, branched or cyclic alkoxyalkyl groups. Alternatively, when a compound having a linear, branched, or cyclic alkoxyalkoxy group is used for the organic semiconductor layer, there is a problem that only an organic transistor having a very low charge mobility can be produced.
In addition, a straight-chain, branched or cyclic alkyl group, straight-chain, branched or cyclic alkoxyalkyl group having 13 or more carbon atoms of X _{1 to} X ₄ as a substituent, or a straight-chain, branched or cyclic alkoxyalkoxy group In this case, there is a problem that only an organic transistor having a low charge mobility can be produced.

The compound represented by the general formula (1) according to the present invention is easily dissolved in an organic solvent, and has an advantage that an organic semiconductor layer can be formed by a wet process.
In particular, when an organic semiconductor layer is formed by a wet process, in the general formula (1), two substituents among the substituents X _{1 to} X ₄ are linear, branched or cyclic alkyl having 5 to 12 carbon atoms. A compound which is a group, a linear, branched or cyclic alkoxyalkyl group having 5 to 12 carbon atoms, or a linear, branched or cyclic alkoxyalkoxy group having 5 to 12 carbon atoms is preferable.

In the general formula (1), more preferably, X ₂ and X ₄ are hydrogen atoms, X ₁ and X ₃ are linear, branched or cyclic alkyl groups having 5 to 12 carbon atoms, and 5 to 12 carbon atoms. A linear, branched or cyclic alkoxyalkyl group, or a linear, branched or cyclic alkoxyalkoxy group having 5 to 12 carbon atoms.
In the general formula (1), more preferably, X ₁ and X ₃ are hydrogen atoms, and X ₂ and X ₄ are linear, branched or cyclic alkyl groups having 5 to 12 carbon atoms, and 5 carbon atoms. A linear, branched or cyclic alkoxyalkyl group of -12, or a linear, branched or cyclic alkoxyalkoxy group of 5 to 12 carbon atoms.

（式中、Ｘ_１１〜Ｘ_１４はそれぞれ独立に、炭素数５〜１２の直鎖、分岐または環状のアルキル基、炭素数５〜１２の直鎖、分岐または環状のアルコキシアルキル基、あるいは炭素数５〜１２の直鎖、分岐または環状のアルコキシアルコキシ基を表す） In general formula (1), a compound represented by general formula (1-A) or general formula (1-B) is more preferable, and a compound represented by general formula (1-A) is more preferable. It is.
Among them, in the compound represented by the general formula (1-A), X ₁₂ and X ₁₄ are linear, branched or cyclic alkyl groups having 5 to 12 carbon atoms, or linear, branched or cyclic groups having 5 to 12 carbon atoms. Compounds that are cyclic alkoxyalkyl groups are preferred.

(In the formula, X _{11 to} X ₁₄ are each independently a linear, branched or cyclic alkyl group having 5 to 12 carbon atoms, a linear, branched or cyclic alkoxyalkyl group having 5 to 12 carbon atoms, or the number of carbon atoms. Represents 5-12 linear, branched or cyclic alkoxyalkoxy groups)

In General Formula (1-A) and General Formula (1-B), X _{11 to} X ₁₄ are each independently a linear, branched or cyclic alkyl group having 5 to 12 carbon atoms, and a straight chain having 5 to 12 carbon atoms. Represents a chain, branched or cyclic alkoxyalkyl group, or a linear, branched or cyclic alkoxyalkoxy group having 5 to 12 carbon atoms. Specific examples of these groups include X _{1 to} X in the general formula (1). _The linear, branched or cyclic alkyl group, the linear, branched or cyclic alkoxyalkyl group exemplified in ₄ or the linear, branched or cyclic alkoxyalkoxy group can be exemplified.

  Specific examples of the compound represented by the general formula (1) according to the present invention include the following compounds, but the present invention is not limited thereto.

〔式中、Ｘ_１〜Ｘ_４は一般式（１）の場合と同じ意味を表す〕 The compound represented by the general formula (1) according to the present invention can be produced with reference to a method known per se. That is, in the compound represented by the general formula (1), for example, an acid (for example, an alkyl sulfonic acid such as methanesulfonic acid or trifluoromethanesulfonic acid) is allowed to act on the compound represented by the general formula (2). Thereafter, it can be produced by reacting a base (for example, pyridine, quinoline) [for example, the method described in Macromolecules, 26,7144 (1993), J. Mater. Chem., 9, 2095 (1999)]. Can be helpful).

[Wherein X _{1 to} X ₄ represent the same meaning as in the general formula (1)]

  The compound represented by the general formula (2) includes, for example, a compound represented by the general formula (3), a compound represented by the general formula (4), and a compound represented by the general formula (5). For example, a palladium catalyst [for example, bis (triphenylphosphine) palladium dichloride, tetrakis (triphenylphosphine) palladium, palladium acetate, palladium / carbon] and a base in the presence of a base. [For example, the method described in Chem. Rev., 95, 2457 (1995), Chem. Rev., 107, 133 (2007), Tetrahedron, 54, 263 (1998) can be referred to].

〔式中、Ｘ_１〜Ｘ_４は一般式（１）と同じ意味を表し、Ｚ_１およびＺ_２は脱離基を表し、Ｍ_１およびＭ_２は金属含有基を表す〕

[Wherein, X _{1 to} X ₄ represent the same meaning as in general formula (1), Z ₁ and Z ₂ represent a leaving group, and M ₁ and M ₂ represent a metal-containing group]

In the general formula (3), Z ₁ and Z ₂ each represent a leaving group, preferably a halogen atom or an —OSO ₂ —R group.
The halogen atom that is a preferred leaving group represented by Z ₁ and Z ₂ is a chlorine atom, a bromine atom, or an iodine atom.
In the —OSO ₂ —R group which is a preferred leaving group represented by Z ₁ and Z ₂ , R is a substituted or unsubstituted aryl group, or a linear, branched or cyclic group which may be substituted with a halogen atom Represents an alkyl group, and more preferably represents a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, or a linear, branched or cyclic alkyl group which may be substituted with a halogen atom having 1 to 10 carbon atoms. More preferably, it represents a linear, branched or cyclic alkyl group which may be substituted with a halogen atom having 1 to 8 carbon atoms.

In the —OSO ₂ —R group, specific examples of the substituted or unsubstituted aryl group represented by R include a substituted or unsubstituted aryl group such as a phenyl group and a 4-methylphenyl group. .
In -OSO 2 _-R group, straight optionally substituted by halogen atom represented by R, specific examples of the alkyl group branched or cyclic, for example, a methyl group, an ethyl group, n- propyl group, Alkyl groups such as isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, cyclopentyl group, cyclohexyl group, n-octyl group, n-decyl group, trifluoromethyl group, chlorodifluoromethyl group And an alkyl group substituted with a halogen atom such as a dichlorofluoromethyl group, a pentafluoroethyl group, and an n-nonafluorobutyl group.
As the —OSO ₂ —R group which is a preferable leaving group represented by Z ₁ and Z ₂ , more preferably, a benzenesulfonyloxy group, a p-toluenesulfonyloxy group, a methanesulfonyloxy group, a trifluoromethanesulfonyloxy group. It is.

In the general formulas (4) and (5), the metal-containing group represented by M ₁ and M ₂ is preferably a boron metal-containing group, a tin metal-containing group, a magnesium metal-containing group, or a zinc metal-containing group. Group, manganese metal-containing group, zirconium metal-containing group, indium metal-containing group, germanium metal-containing group, lead metal-containing group, bismuth metal-containing group, or copper metal-containing group, more preferably boron metal-containing group, tin It represents a metal-containing group, a magnesium metal-containing group, or a zinc metal-containing group.

The boron metal-containing group is preferably a group represented by the general formula (M-1).
_{-B (OR 0) (OR 00} ) (M-1)
(In the formula, R ₀ and R ₀₀ represent a hydrogen atom or an alkyl group, and R ₀ and R ₀₀ may be bonded to each other to form a cyclic alkylene group or an arylene group)
In General Formula (M-1), R ₀ and R ₀₀ each represent a hydrogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
When R ₀ and R ₀₀ are bonded to each other to represent a cyclic alkylene group, it preferably represents a cyclic alkylene group having 2 to 10 carbon atoms.
In addition, when R ₀ and R ₀₀ are bonded to each other to represent an arylene group, it preferably represents a 1,2-phenylene group having 6 to 10 carbon atoms which may be substituted with an alkyl group.

The tin metal-containing group is preferably a group represented by the general formula (M-2).
_{-Sn (R 000) 3 (M} -2)
(In the formula, R ₀₀₀ represents an alkyl group)
In General Formula (M-2), _R000 represents an alkyl group, and preferably represents an alkyl group having 1 to 8 carbon atoms.

The magnesium metal-containing group is preferably a group represented by the general formula (M-3).
-MgZ ₀ (M-3)
(In the formula, Z ₀ represents a halogen atom)
In General Formula (M-3), Z ₀ represents a halogen atom, preferably a chlorine atom, a bromine atom, or an iodine atom.

The zinc metal-containing group is preferably a group represented by the general formula (M-4).
-ZnZ ₀₀ (M-4)
(In the formula, Z ₀₀ represents a halogen atom)
In General Formula (M-4), Z ₀₀ represents a halogen atom, preferably a chlorine atom, a bromine atom, or an iodine atom.

In addition, the compound represented by the general formula (1) according to the present invention may be produced in a mold that forms a solvate with a solvent used (for example, an aromatic hydrocarbon solvent such as toluene). However, in the organic transistor of the present invention, such a solvate as well as a non-solvate of the compound represented by the general formula (1) can be used.
When the compound represented by the general formula (1) is used in an organic transistor, a purification method such as a recrystallization method, a column chromatography method, a sublimation purification method, or a combination of these methods increases the purity. It is preferred to use

The organic transistor of the present invention is characterized in that the organic semiconductor layer contains at least one compound represented by the general formula (1), which has a high charge mobility, which is unconventional, It is possible to provide an organic transistor having a large on / off ratio and excellent storage stability.

The organic transistor usually has a source electrode, a drain electrode and a gate electrode, a gate insulating layer, and an organic semiconductor layer. In the organic transistor of the present invention, the organic semiconductor layer has the general formula (1). It contains at least one compound represented by

The form of the organic transistor of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an embodiment of the organic transistor of the present invention.
In the form of this organic transistor, a gate electrode 21 is provided on a substrate 11, a gate insulating layer 31 is laminated on the gate electrode, and a source electrode 61 and a drain electrode formed on the gate electrode at predetermined intervals. 41 is formed, and an organic semiconductor layer 51 is further stacked thereon (bottom gate / bottom contact structure).

In the form of the organic transistor shown in FIG. 2, the gate electrode 22 is provided on the substrate 12, the gate insulating layer 32 is laminated on the gate electrode, and the organic semiconductor layer 52 is laminated thereon. Further, a source electrode 62 and a drain electrode 42 are formed at a predetermined interval thereon (bottom gate / top contact structure).

In the form of the organic transistor shown in FIG. 3, the source electrode 63 and the drain electrode 43 are formed on the substrate 13 at a predetermined interval, and the organic semiconductor layer 53 is laminated thereon, A gate insulating layer 33 is laminated thereon, and a gate electrode 23 is further provided thereon (top gate / bottom contact structure).

In the form of the organic transistor shown in FIG. 4, the organic semiconductor layer 54 is laminated on the substrate 14, and the source electrode 64 and the drain electrode 44 are formed on the substrate 14 at a predetermined interval. A gate insulating layer 34 is laminated thereon, and a gate electrode 24 is further provided thereon (top gate / top contact structure).

In the organic transistor having such a structure, the organic semiconductor layer forms a channel region, and the current flowing between the source electrode and the drain electrode is controlled by the voltage applied to the gate electrode, thereby turning on / off. Operate.

The substrate used in the organic transistor of the present invention is not particularly limited, but generally, glass, quartz, silicon single crystal, polycrystalline silicon, amorphous silicon, a plastic substrate, or the like can be used. Furthermore, a composite substrate in which these are combined can be used, and may have a single-layer structure or a multilayer structure.

Examples of the plastic substrate include polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, triacetylcellulose, and cellulose acetate propionate. A substrate is mentioned.
Note that when a conductive substrate, for example, silicon is used for the substrate, the substrate can also serve as the gate electrode.

In the organic transistor of the present invention, materials used for the source electrode, the drain electrode, and the gate electrode are not particularly limited, and any material can be used as long as it is a conductive material.

As electrode materials, for example, indium tin oxide alloy (ITO), tin oxide (NESA), indium zinc oxide (IZO), molybdenum oxide, gold, silver, platinum, copper, indium, aluminum, magnesium, nickel, chromium, iron , Tin, tantalum, palladium, tellurium, iridium, ruthenium, germanium, tungsten, molybdenum, lithium, beryllium, sodium, potassium, calcium, zinc, magnesium / indium alloy, magnesium / copper alloy, magnesium / silver alloy, magnesium / aluminum alloy , Chromium / molybdenum alloy, aluminum / lithium alloy, aluminum / scandium / lithium alloy, sodium / potassium alloy and other metals and alloys, fluorine-doped zinc oxide, silicon with improved conductivity Examples thereof include silicon-based materials such as single crystal, polycrystalline silicon, and amorphous silicon, and carbon materials such as carbon black, graphite, and glassy carbon. More preferably, indium tin oxide alloy, gold, silver, platinum, copper, Indium, aluminum, silicon materials with improved conductivity, and carbon materials. These can be used in various forms such as bulk, flakes, and fine particles.

In addition, as an electrode material, a conductive polymer whose conductivity has been improved by doping treatment (eg, a polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene, polyethylenedioxythiophene (PEDOT) and polystyrenesulfonic acid complex). Are also preferably used.
In addition, these electrode materials may be used individually by 1 type, or may be used together.
Among the electrode materials listed above, the source electrode and the drain electrode are preferably those having a small electric resistance at the contact surface with the organic semiconductor layer.

A method for forming each electrode is not particularly limited. For example, a conductive material can be formed using a method such as vapor deposition or sputtering, and patterned into a desired shape by lithograph or etching treatment. it can.
In addition, when an electrode is formed using a conductive polymer or conductive fine particles, a conductive polymer solution or dispersion, or a conductive fine particle dispersion may be patterned by an ink jet method. It may be formed by lithography or laser ablation. Furthermore, a method of patterning an ink containing a conductive polymer or conductive fine particles, a conductive paste (silver paste, carbon paste, etc.) by a printing method such as relief printing, intaglio printing, planographic printing, and screen printing can also be used.

The film thickness of the source electrode and the drain electrode is not particularly limited, but in general, it is preferably set in the range of several nm to several hundred μm, more preferably 1 nm to 100 μm, and still more preferably 10 nm. ˜20 μm.
The source electrode and the drain electrode are arranged so as to face each other, and the interval (channel length) is generally preferably set in the range of several hundred nm to several mm, more preferably 100 nm to It is 1 mm, More preferably, it is 1 micrometer-500 micrometers.

Further, the surface of the source electrode and the drain electrode is, for example, an aliphatic alkyl thiol compound such as 4,4-dimethylpentanethiol, perfluorohexanethiol, perfluoroheptanethiol, and perfluorooctanethiol, for example, 2,4,6. -It may be modified with an aromatic thiol compound such as trifluorothiophenol, pentafluorothiophenol, 4-trifluoromethylthiophenol.

As a material used for the gate insulating layer, various insulating materials can be used, and an inorganic insulator or an organic polymer compound is preferable.
As the inorganic insulator, silicon oxide (SiO ₂ ), silicon nitride, aluminum oxide, aluminum nitride, tantalum oxide, titanium oxide, tin oxide, vanadium oxide, barium strontium titanate, barium zirconate titanate, lead zirconate titanate , Lead lanthanum titanate, strontium titanate, barium titanate, barium magnesium fluoride, bismuth titanate, strontium bismuth titanate, strontium bismuth tantalate, bismuth tantalate niobate, trioxide yttrium, and more Preferred are silicon oxide, silicon nitride, aluminum oxide, tantalum oxide, and titanium oxide.

Examples of the method for forming a gate insulating layer made of an inorganic insulator include a vacuum deposition method, a molecular beam epitaxial growth method, an ion cluster beam method, a low energy ion beam method, an ion plating method, a CVD method, a sputtering method, and atmospheric pressure plasma. Dry processes such as spray coating, spray coating, spin coating, blade coating, dip coating, casting, roll coating, bar coating, die coating, air knife, slide hopper, and extrusion Examples thereof include a wet process such as a coating method, various printing methods, and an inkjet method, and can be appropriately selected and applied according to the characteristics of the material to be used. Further, when a silicon-based material is used as the gate electrode and the gate insulating layer is formed before the organic semiconductor is formed, it may be formed by a thermal oxidation method.

Examples of the organic polymer compound used for the gate insulating layer include polyimide, polyamide, polyester, polyacrylate, a photo-radical polymerization photo-curing resin, a photo-cation polymerization photo-curing resin, or a copolymer containing an acrylonitrile component. Polyvinylphenol, polyvinyl alcohol, polystyrene, novolac resin, polyvinylidene fluoride, cyanoethyl pullulan, and the like can be used. As a method for forming a gate insulating layer using an organic polymer compound, a wet process is preferable.
The insulating material used for the gate insulating layer may be used alone or in combination.

In addition, when using, for example, silicon oxide as an inorganic insulator for the gate insulating layer, the surface of silicon oxide serving as an interface with the organic semiconductor layer is, for example, hexamethyldisilazane, octadecyltrimethoxysilane, octyltrichlorosilane, Octadecyltrichlorosilane, benzyltrichlorosilane, 1-hexylphosphonic acid, 1-octylphosphonic acid, 1-hexadecylphosphonic acid, 3,7,11,15-tetramethyl-1-hexadecylphosphonic acid, etc. It may be processed.
In addition, when an organic polymer compound is used for the gate insulating layer and the organic semiconductor layer is formed after forming the gate insulating layer, the organic semiconductor layer is subjected to a rubbing treatment on the gate insulating layer made of the organic polymer compound. May be formed.

The thickness of the gate insulating layer is not particularly limited, but generally it is preferably set in the range of several nm to several tens of μm, more preferably 5 nm to 10 μm, and still more preferably 10 nm to 5 μm. It is.

The organic transistor of the present invention comprises at least one compound represented by the general formula (1) in the organic semiconductor layer, and the compound represented by the general formula (1) is singly used alone. You may use, and may use multiple types together.

Furthermore, the organic semiconductor layer includes at least one compound represented by the general formula (1) and another carrier transporting compound (for example, polyacetylene derivative, polythiophene derivative, polythienylene vinylene derivative, polyphenylene derivative, polyphenylene vinylene derivative). , Polypyrrole derivatives, polyaniline derivatives, polyarylamine derivatives, polyquinoline derivatives, perylene derivatives, tetracene derivatives, pentacene derivatives, phthalocyanine derivatives, and the like). In this case, the content of the compound represented by the general formula (1) is preferably 20% by mass or more, and more preferably 50% by mass or more.

Furthermore, the organic semiconductor layer may be formed of at least one compound represented by the general formula (1) and a polymer compound.
Examples of such polymer compounds include polyacrylic acid derivatives, polymethacrylic acid derivatives, poly (cyclohexyl methacrylate) derivatives, polyethylene derivatives, polypropylene derivatives, polyisoprene derivatives, polybutadiene derivatives, polyisobutylene derivatives, polymethylpentene derivatives,
Poly (vinylcyclohexane) derivatives, polystyrene derivatives, poly (4-methylstyrene) derivatives, poly (α-methylstyrene) derivatives, poly (α-vinylnaphthalene) derivatives, poly (vinyltoluene) derivatives, poly (chlorotrifluoroethylene) ) Derivatives, poly (4-vinylbiphenyl) derivatives, poly (2-methyl-1,3-butadiene) derivatives, poly (styrene / acrylonitrile) copolymers, poly (styrene / butadiene) copolymers, polyvinyl chloride derivatives And polyethylene terephthalate derivatives, polybutylene terephthalate derivatives, nylon derivatives, polyester derivatives, polyimide derivatives, polyphenol derivatives, cellulose derivatives, vinylon derivatives, and the like.
These polymer compounds may be used alone or in combination.
In addition, when forming an organic-semiconductor layer using together at least 1 type of compound represented by General formula (1), and a high molecular compound, containing at least 1 type of compound represented by General formula (1) The amount is preferably 5% by mass or more, more preferably 20% by mass or more based on the polymer compound.

  The organic transistor of the present invention functions as a p-type (holes function as a carrier) organic transistor or an n-type (electrons function as a carrier) organic transistor, preferably as a p-type organic transistor. It is preferred to use.

The method for forming the organic semiconductor layer is not particularly limited, and a known formation method can be used.
Examples of the formation method include vacuum deposition, molecular beam epitaxial growth, ion cluster beam, low energy ion beam, ion plating, CVD, sputtering, plasma polymerization, thermal transfer, and laser transfer. Dry process, spray coat method, spin coat method, blade coat method, dip coat method, cast method, roll coat method, bar coat method, die coat method, LB method (Langmuir / Blodget method), various printing methods, ink jet method And wet processes such as

When the organic semiconductor layer is formed by a wet process, a solution in which at least one compound represented by the general formula (1) is dissolved or dispersed in a solvent is used.
Examples of such solvents include alcohol solvents such as water, methanol, ethanol, isopropyl alcohol, and butanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as ethyl acetate and butyl acetate; Ether solvents such as ether, dioxane, tetrahydrofuran, anisole, hydrocarbon solvents such as hexane, octane, toluene, xylene, ethylbenzene, cumene, 1,2,3,4-tetrahydronaphthalene, dichloromethane, chloroform, dichloroethane, tetrachloroethane , Halogenated hydrocarbon solvents such as tetrachloroethylene, chlorobenzene, fluorobenzene, dichlorobenzene, trichlorobenzene, acetonitrile, propionite Nitrile solvents such as methoxyacetonitrile, glutarodinitrile, benzonitrile, aprotic such as dimethyl sulfoxide, sulfolane, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone And organic solvents such as a polar solvent. These solvents may be used alone or in combination.
The concentration of at least one compound represented by the general formula (1) in the solvent is not particularly limited, but is generally 0.01 to 20% by mass, more preferably 0.05 to It is preferable to adjust to about 15% by mass.
The film thickness of the organic semiconductor layer is not particularly limited, but in general, it is preferably set in the range of several nm to several tens of μm, more preferably 1 nm to 10 μm, still more preferably 5 nm to 1 μm.

In the present invention, after the organic semiconductor layer is formed, a post-treatment may be further performed as desired.
For example, after the organic semiconductor layer is formed, heat treatment may be performed to reduce the distortion of the film thickness generated during the formation or to improve the generated pinholes.
In addition, it may be preferable to perform heat treatment for the purpose of controlling the arrangement and orientation of molecules in the organic semiconductor layer.
Although it does not restrict | limit especially regarding the temperature of heat processing, About room temperature-about 200 degreeC, Preferably, it implements at 40 degreeC-150 degreeC. The heat treatment may be performed in the air or in an inert gas atmosphere such as nitrogen or argon.

In the organic transistor of the present invention, the organic semiconductor layer may be subjected to a doping treatment if desired.
In addition, as a dopant, both a donor-type dopant and an acceptor-type dopant can be used, and it is preferable to use an acceptor-type dopant.
As the donor dopant, any compound having a function of donating electrons to the organic compound of the organic semiconductor layer can be preferably used.
Examples of the donor dopant include alkali metals such as Li, Na, K, Rb, and Cs, alkaline earth metals such as Ca, Sr, and Ba, Y, La, Ce, Pr, Nd, Sm,
Rare earth metals such as Eu, Gd, Tb, Dy, Ho, Er, Yb, ammonium ions,
Examples include R ₄ P ⁺ (R represents an alkyl group), R ₄ As ⁺ (R represents an alkyl group), R ₃ S ⁺ (R represents an alkyl group), acetylcholine, and the like.

As the acceptor dopant, any compound having a function of removing electrons from the organic compound of the organic semiconductor layer can be preferably used.
Examples of the acceptor dopant include halogen compounds such as Cl ₂ , Br ₂ , I ₂ , ICl, ICl ₃ , IBr, and IF, PF ₅ , AsF ₅ , SbF ₅ , BF ₃ , BCl ₃ ,
Lewis acids such as BBr ₃ and SO ₃ , HF, HCl, HNO ₃ , H ₂ SO ₄ , HClO ₄ ,
Protic acids such as FSO ₃ H, ClSO ₃ H, CF ₃ SO ₃ H, organic acids such as acetic acid, formic acid and amino acids, FeCl ₃ , FeOCl, TiCl ₄ , ZrCl ₄ , HfCl ₄ , NbF ₅ ,
Transition metal compounds such as NbCl ₅ , TaCl ₅ , MoCl ₅ , WF ₅ , WCl ₆ , UF ₆ , LnCl ₃ (Ln = La, Ce, Nd, Pr and other lanthanoids and Y), Cl ⁻ , Br ⁻ ,
Examples thereof include electrolyte anions such as I ⁻ , ClO ₄ ⁻ , PF ₆ ⁻ , AsF ₅ ⁻ , SbF ₆ ⁻ , BF ₄ ⁻ and sulfonate anions.
As a doping method, a method of introducing a dopant after forming an organic semiconductor layer, or a method of introducing a dopant at the time of forming the organic semiconductor layer can be applied.

Moreover, the organic transistor of this invention can also provide a gas barrier layer in the whole or part of the outer peripheral surface of an organic transistor in order to reduce the influence of oxygen, moisture, etc. in the atmosphere. Examples of the material for forming the gas barrier layer include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl chloride, and polyvinylidene chloride. Furthermore, the inorganic insulator mentioned as a material used for a gate insulating layer can also be used for formation of a gas barrier layer.
The organic transistor of the present invention can be used for, for example, a liquid crystal display element, an organic electroluminescent element, electronic paper, various sensors, RFIDs (radio frequency identification cards), and the like.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.
Example 1
A thermal oxide film (SiO ₂ ) having a thickness of 200 nm was formed on a silicon substrate having a resistivity of 0.02 Ω · cm as a gate electrode. Here, the silicon substrate itself becomes the gate electrode, and the SiO ₂ layer formed on the surface of the silicon substrate becomes the gate insulating layer. On top of this, the compound of Exemplified Compound No. 4 was deposited in a thickness of 30 nm under vacuum (5 × 10 ⁻⁴ Pa) at a deposition rate of 0.03 nm / sec to form an organic semiconductor layer. Further, a source electrode and a drain electrode were formed thereon by vapor-depositing gold using a mask. The source electrode and drain electrode had a thickness of 40 nm, a channel width of 5 mm, and a channel length of 20 μm.
The organic transistor manufactured as described above exhibited characteristics as a p-type transistor element. The charge mobility was determined from the saturation region of the current-voltage (IV) characteristics of the organic transistor.
Further, the drain current value was measured when the drain bias was −50 V and the gate bias was −50 V and 0 V, and the current on / off ratio was obtained.
Furthermore, after storing the produced organic transistor element in the atmosphere at 25 ° C. for one month, the charge mobility and the on / off ratio of the current were measured again. The measurement results are shown in Table 1.

(Examples 2 to 7)
In Example 1, instead of using the compound of Example Compound No. 4 in forming the organic semiconductor layer, the compound of Example Compound No. 14 (Example 2), the compound of Example Compound No. 16 (Example 3), and the Example Compound Except for using the compound of No. 33 (Example 4), the compound of Example Compound No. 35 (Example 5), the compound of Example Compound No. 50 (Example 6), and the compound of Example Compound No. 58 (Example 7) An organic transistor was prepared by the method described in Example 1.
Further, the characteristics of the organic transistor were examined by the method described in Example 1, and the results are shown in Table 1.

さらに、実施例１に記載の方法により、有機トランジスタの特性を調べ、結果を第１表に示した。 (Comparative Example 1)
In Example 1, in forming the organic semiconductor layer, Example 1 was used except that the compound of the formula (A) (the compound described in Non-Patent Document 4) was used instead of the compound of Exemplified Compound No. 4. An organic transistor was produced by the method described.

Further, the characteristics of the organic transistor were examined by the method described in Example 1, and the results are shown in Table 1.

さらに、実施例１に記載の方法により、有機トランジスタの特性を調べ、結果を第１表に示した。 (Comparative Example 2)
In Example 1, in forming the organic semiconductor layer, Example 1 was used except that the compound of the formula (A) (the compound described in Non-Patent Document 5) was used instead of the compound of Example Compound No. 4. An organic transistor was produced by the method described.

Further, the characteristics of the organic transistor were examined by the method described in Example 1, and the results are shown in Table 1.

(Comparative Example 3)
In Example 1, an organic transistor was produced by the method described in Example 1 except that the compound of Formula (C) was used instead of the compound of Example Compound No. 4 when forming the organic semiconductor layer. .

(Comparative Example 4)
In Example 1, an organic transistor was produced by the method described in Example 1 except that the compound of Formula (D) was used instead of the compound of Example Compound No. 4 when forming the organic semiconductor layer. .

(Example 8)
A thermal oxide film (SiO ₂ ) having a thickness of 200 nm was formed on a silicon substrate having a resistivity of 0.02 Ω · cm as a gate electrode. Here, the silicon substrate itself becomes the gate electrode, and the SiO ₂ layer formed on the surface of the silicon substrate becomes the gate insulating layer. When the silicon substrate was heated to 80 ° C. and a chlorobenzene solution (concentration: 0.3% by mass) of the compound of Exemplified Compound No. 29 was applied thereon, the chlorobenzene evaporated to give an exemplary compound having a thickness of 50 nm. An organic semiconductor layer made of the compound of No. 29 was formed. Further, a source electrode and a drain electrode were formed thereon by vapor-depositing gold using a mask. The source electrode and drain electrode had a thickness of 40 nm, a channel width of 5 mm, and a channel length of 20 μm.
Furthermore, when the characteristics of the organic transistor were examined by the method described in Example 1, the mobility was 8.7 × 10 ⁻¹ (cm ² / Vsec), and the current on / off ratio was 4.6. × 10 ⁶

Example 9
In Example 8, an organic transistor was prepared by the method described in Example 8 except that the compound of Exemplified Compound No. 19 was used instead of the compound of Exemplified Compound No. 29 in forming the organic semiconductor layer. .
Further, when the characteristics of the organic transistor were examined by the method described in Example 1, the mobility was 1.8 (cm ² / Vsec), and the current on / off ratio was 5.4 × 10 ⁶ . there were.

(Example 10)
In Example 8, an organic transistor was produced by the method described in Example 8 except that the compound of Exemplified Compound No. 21 was used instead of the compound of Exemplified Compound No. 29 in forming the organic semiconductor layer. .
Further, when the characteristics of the organic transistor were examined by the method described in Example 1, the mobility was 1.2 (cm ² / Vsec), and the current on / off ratio was 4.7 × 10 ⁶ . there were.

(Example 11)
In Example 8, an organic transistor was produced by the method described in Example 8 except that the compound of Exemplified Compound No. 29 was used instead of the compound of Exemplified Compound No. 29 in forming the organic semiconductor layer. .
Further, when the characteristics of the organic transistor were examined by the method described in Example 1, the mobility was 1.6 (cm ² / Vsec), and the current on / off ratio was 6.4 × 10 ⁶ . there were.

(Example 12)
In Example 8, an organic transistor was produced by the method described in Example 8 except that the compound of Exemplified Compound No. 29 was used instead of the compound of Exemplified Compound No. 29 in forming the organic semiconductor layer. .
Furthermore, when the characteristics of the organic transistor were examined by the method described in Example 1, the mobility was 9.8 × 10 ⁻¹ (cm ² / Vsec), and the current on / off ratio was 5.7. × 10 ⁶

(Example 13)
In Example 8, when the organic semiconductor layer was formed, an organic transistor was produced by the method described in Example 8, except that the compound of exemplary compound number 54 was used instead of the compound of exemplary compound number 29. .
Further, when the characteristics of the organic transistor were examined by the method described in Example 1, the mobility was 1.4 (cm ² / Vsec), and the current on / off ratio was 5.6 × 10 ⁶ . there were.

(Comparative Example 5)
In Example 8, an organic transistor was produced by the method described in Example 8, except that the compound of formula (E) was used instead of the compound of Example Compound No. 29 in forming the organic semiconductor layer. .
Further, when the characteristics of the organic transistor were examined by the method described in Example 1, the mobility was 3.4 × 10 ⁻¹ (cm ² / Vsec), and the current on / off ratio was 4.6. × 10 ⁶

(Comparative Example 6)
In Example 8, an organic transistor was produced by the method described in Example 8, except that the compound of formula (F) was used instead of the compound of Example Compound No. 29 in forming the organic semiconductor layer. .
Furthermore, when the characteristics of the organic transistor were examined by the method described in Example 1, the mobility was 2.7 × 10 ⁻¹ (cm ² / Vsec), and the current on / off ratio was 5.1. × 10 ⁶

From Table 1, the organic transistor using the compound represented by the general formula (1) has high charge mobility, a large current on / off ratio, and has excellent characteristics as an organic transistor. Further, it is clear that the organic transistor is excellent in stability in which change with time is suppressed.

The organic transistor of the present invention has high charge mobility, a large current on / off ratio, and excellent storage stability. The liquid crystal display element, organic electroluminescent element, electronic paper, various sensors, RFIDs (radio frequency identification cards).

11: Substrate 21: Gate electrode 31: Gate insulating layer 41: Drain electrode 51: Organic semiconductor layer 61: Source electrode

12: Substrate 22: Gate electrode 32: Gate insulating layer 42: Drain electrode 52: Organic semiconductor layer 62: Source electrode

13: Substrate 23: Gate electrode 33: Gate insulating layer 43: Drain electrode 53: Organic semiconductor layer 63: Source electrode

14: Substrate 24: Gate electrode 34: Gate insulating layer 44: Drain electrode 54: Organic semiconductor layer 64: Source electrode

Claims (1)

An organic transistor having an organic semiconductor layer, wherein the organic semiconductor layer contains at least one compound selected from compounds represented by the general formula (1).

[Wherein, X _{1 to} X ₄ each independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 5 to 12 carbon atoms, a linear, branched or cyclic alkoxyalkyl group having 5 to 12 carbon atoms, or represents a straight-chain, branched or cyclic alkoxyalkoxy group having 5 to 12 carbon atoms (, X ₁ to X ₄ are not simultaneously represent a hydrogen atom)]

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