JP5444936B2 - Organic semiconductor transistor - Google Patents

Description

  The present invention relates to an organic semiconductor transistor.

  Thin film transistors are widely used as display switching elements such as liquid crystal display elements. Conventionally, a thin film transistor is manufactured using amorphous or polycrystalline silicon.

  On the other hand, research on organic semiconductors represented by organic EL (Electro-Luminescence) elements and the like has been actively conducted in recent years. At the same time, research has been reported to replace organic materials with silicon materials and incorporate them into circuits utilizing the characteristics of light weight and flexibility.

  As an organic substance used for such a thin film transistor, a low molecular compound or a high molecular compound is used. As low molecular weight compounds, polyacene compounds such as pentacene and tetracene (for example, refer to Patent Documents 1 to 3) and phthalocyanine compounds such as copper phthalocyanine (for example, refer to Patent Documents 4 and 5) have been proposed.

  Examples of the polymer compound include aromatic oligomers such as sexithiophene (see, for example, Patent Document 6), polymer compounds such as polythiophene, polythienylene vinylene, and poly (p-phenylene vinylene) (for example, Patent Documents 7 to 7). 10 and Non-Patent Document 1).

JP-A-5-55568 JP-A-10-270712 JP 2001-94107 A Japanese Patent Laid-Open No. 5-190877 JP 2000-174277 A JP-A-8-264805 JP-A-8-228034 JP-A-8-228035 Japanese Patent Laid-Open No. 10-125924 Japanese Patent Laid-Open No. 10-190001

Appl.Phys.Lett., 73,108 (1998)

  An object of the present invention is to provide an organic semiconductor transistor in which a decrease in charge mobility is less than that of 13,6-N-sulfinylacetamidopentacene.

The above problem is solved by the following means. That is,
The invention according to claim 1
A plurality of electrodes;
An organic semiconductor layer containing at least one compound represented by the following general formula (I);
It is an organic semiconductor transistor provided with.

In general formula (I), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and A represents an aromatic Represents a heterocyclic residue containing at least one nitrogen atom for forming a group 6-membered heterocyclic ring, and n represents an integer of 1 to 3.

The invention according to claim 2
The organic semiconductor transistor according to claim 1, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (III).

In general formula (III), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and R ² represents A hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, or a substituted group Alternatively, it represents an unsubstituted aryloxy group having 6 to 10 carbon atoms, and n represents an integer of 1 to 3.

The invention according to claim 3
The organic semiconductor transistor according to claim 1, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (II).

In general formula (II), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and n is 1 Represents an integer of 3 or less.

The invention according to claim 4
4. The organic semiconductor transistor according to claim 1, wherein R ¹ is an unsubstituted linear alkyl group having 4 to 8 carbon atoms.

The invention according to claim 5
The plurality of electrodes are a source electrode, a drain electrode and a gate electrode;
Furthermore, an insulating layer is provided,
The gate electrode is provided apart from both the source electrode and the drain electrode;
The organic semiconductor layer is provided in contact with both the source electrode and the drain electrode,
The insulating layer is provided between the organic semiconductor layer and the gate electrode,
The organic semiconductor transistor according to claim 1, which is a field effect type.

The invention according to claim 6
The plurality of electrodes are a source electrode, a drain electrode and a gate electrode;
The gate electrode is provided apart from both the source electrode and the drain electrode;
The organic semiconductor layer is provided in contact with both the source electrode and the drain electrode,
The organic semiconductor transistor according to any one of claims 1 to 4, which is of an electrostatic induction type.

According to the first aspect of the present invention, an organic semiconductor transistor with less reduction in charge mobility than that of 13,6-N-sulfinylacetamidopentacene is provided.
According to the invention concerning Claim 2, the organic-semiconductor transistor with little fall of charge mobility is provided compared with 13, 6- N-sulfinyl acetamide pentacene.
According to the third aspect of the present invention, an organic semiconductor transistor with less reduction in charge mobility than that of 13,6-N-sulfinylacetamidopentacene is provided.
According to the invention of claim 4, there is provided an organic semiconductor transistor in which R ^{1 in the} general formula (I) is less reduced in charge mobility than a compound in which R ¹ is not an unsubstituted linear alkyl group having 4 to 8 carbon atoms. Provided.
According to the invention which concerns on Claim 5, compared with 13, 6- N-sulfinyl acetamido pentacene, the organic-semiconductor transistor with few fall of charge mobility is provided.
According to the sixth aspect of the present invention, there is provided an organic semiconductor transistor in which the decrease in charge mobility is less than that of 13,6-N-sulfinylacetamidopentacene.

It is the schematic block diagram which showed an example of the layer structure of the organic-semiconductor transistor of this embodiment. It is the schematic block diagram which showed an example of the layer structure of the organic-semiconductor transistor of other embodiment. It is the schematic block diagram which showed an example of the layer structure of the organic-semiconductor transistor of other embodiment. It is the schematic block diagram which showed an example of the layer structure of the organic-semiconductor transistor of other embodiment.

  The organic semiconductor transistor of this embodiment includes a plurality of electrodes and an organic semiconductor layer containing at least one compound represented by the following general formula (I). First, the compound represented by the general formula (I) will be described, and then the organic semiconductor transistor of this embodiment will be described.

<Compound represented by formula (I)>

In general formula (I), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and A represents an aromatic Represents a heterocyclic residue containing at least one nitrogen atom for forming a group 6-membered heterocyclic ring, and n represents an integer of 1 to 3.

  An organic semiconductor transistor comprising a nitrogen-containing heterocyclic compound represented by the general formula (I) in an organic semiconductor layer has been found to be easy to produce and excellent in charge transport ability and film formability. It came to be completed.

Specific examples of R ¹ in the general formula (I) include the following groups.
In general formula (I), the alkyl group represented by R ¹ has 1 to 20 carbon atoms. From the viewpoint of solubility in an organic solvent, the number of carbon atoms of the alkyl group represented by R ¹ is preferably 1 or more and 12 or less, and more preferably 4 or more and 8 or less.
The alkyl group represented by R ¹ may be linear, branched or cyclic, and is preferably a linear alkyl group from the viewpoint of solubility in an organic solvent.
The alkyl group represented by R ¹ may have a substituent, but is preferably an unsubstituted alkyl group from the viewpoint of having a hole transporting ability and improving solubility.

In the general formula (I), the alkoxy group represented by R ¹ has 1 to 20 carbon atoms. From the viewpoint of solubility in an organic solvent, the number of carbon atoms of the alkoxy group represented by R ¹ is more preferably 1 or more and 12 or less, and further preferably 4 or more and 8 or less.
The alkoxy group represented by R ¹ may be linear, branched or cyclic, and is preferably a linear alkoxy group from the viewpoint of solubility in an organic solvent.
The alkoxy group represented by R ¹ may have a substituent, but is preferably an unsubstituted alkoxy group from the viewpoints of solubility, crystallinity, hole transportability, and the like.

Among these, R ¹ in the general formula (I) is preferably a hydrogen atom, an unsubstituted alkyl group having 1 to 20 carbon atoms, or an unsubstituted alkoxy group having 1 to 20 carbon atoms, It is more preferably an unsubstituted alkyl group having 1 to 12 carbon atoms or an unsubstituted alkoxy group having 1 to 12 carbon atoms, an unsubstituted linear alkyl group having 4 to 8 carbon atoms or an unsubstituted group. A straight-chain alkoxy group having 4 to 8 carbon atoms is more preferable, and an unsubstituted straight-chain alkyl group having 4 to 8 carbon atoms is more preferable.
In the compound represented by the general formula (I), a decrease in charge mobility is suppressed, and further, when R ¹ in the general formula (I) is an alkyl group, it is considered that charge transfer is more advantageous. Further, when R ¹ in the general formula (I) is an alkoxy group, it is considered that the ionization potential is lowered and charge injection from the electrode is improved.

The substitution position of R ¹ in the general formula (I) is preferably the 3-position or the 4-position on the benzene ring with respect to the thiophene ring (1-position) from the viewpoint of hole transport ability, and is the 4-position. Is more preferable from the viewpoint of improving the molecular orientation and suppressing the decrease in charge mobility.
In general formula (I), n represents an integer of 1 to 3, and is preferably 1 or 2.

  In general formula (I), A represents a heterocyclic residue containing at least one nitrogen atom for forming an aromatic heterocyclic six-membered ring. The aromatic hetero 6-membered ring formed by A is preferably a triazine, a triazine derivative, a pyrazine, or a pyrazine derivative from the viewpoint of exhibiting charge transport ability.

  Therefore, the compound represented by the general formula (I) is preferably at least one of a pyrazine derivative represented by the following general formula (II) and a triazine derivative represented by the following general formula (III).

In general formula (II), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and n represents each Independently, an integer of 1 to 3 is represented.
R ¹ and n in the general formula (II), the general formula (I) are each as R ¹ and n synonymous in a preferred range is also the same.

In the pyrazine derivative represented by the general formula (II), thiophene groups are introduced at the 2nd and 6th positions of the pyrazine ring. The pyrazine derivative represented by the general formula (II) having such a structure is excellent in solubility in an organic solvent, and the film formability is improved. Among them, when R ¹ is an alkyl group having 1 to 12 carbon atoms, solubility in an organic solvent is further excellent, and when it is an unsubstituted alkyl group, it is suitable as a hole transport material.
In addition, the pyrazine derivative represented by the general formula (II) in which a thiophene group is introduced at the 2-position and the 6-position of the pyrazine ring is excellent in terms of molecular orientation when it is thinned.

In general formula (III), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and R ² represents A hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, or a substituted group Alternatively, it represents an unsubstituted aryloxy group having 6 to 10 carbon atoms, and n represents an integer of 1 to 3.

R ¹ and n in the general formula (III), general formula (I) are each as R ¹ and n synonymous in a preferred range is also the same.

In the general formula (III), the alkyl group represented by R ² has 1 to 10 carbon atoms. From the viewpoint of solubility in an organic solvent, the number of carbon atoms of the alkyl group represented by R ² is more preferably 1 or more and 4 or less.
The alkyl group represented by R ² may be linear, branched or cyclic, and is preferably a linear alkyl group from the viewpoint of solubility in an organic solvent.
The alkyl group represented by R ² may have a substituent, but is preferably an unsubstituted alkyl group from the viewpoint of solubility in an organic solvent.

In general formula (III), the alkoxy group represented by R ² has 1 to 20 carbon atoms. From the viewpoint of solubility in organic solvents, the number of carbon atoms of the alkoxy group represented by R ² is preferably 1 or more and 10 or less, more preferably 1 or more and 4 or less, and the methoxy group is Further preferred.
The alkoxy group represented by R ² may be linear, branched or cyclic, and is preferably a linear alkoxy group from the viewpoint of solubility in an organic solvent.
The alkoxy group represented by R ² may have a substituent, but is preferably an unsubstituted alkoxy group from the viewpoint of solubility in an organic solvent.

In the general formula (III), the aryl group represented by R ² has 6 to 10 carbon atoms. From the viewpoint of solubility in an organic solvent, the aryl group represented by R ² is more preferably a phenyl group.
Examples of the substituent of the aryl group represented by R ² include an alkyl group and a halogen atom, and an alkyl group having 1 to 10 carbon atoms is preferable.

In the general formula (III), the aryloxy group represented by R ² has 6 to 10 carbon atoms. From the viewpoint of solubility in an organic solvent, the aryloxy group represented by R ² is more preferably a phenoxy group.
Examples of the substituent of the aryloxy group represented by R ² include an alkyl group and a halogen atom, and an alkyl group having 1 to 10 carbon atoms is preferable.

Among these, R ² in the general formula (III) is preferably a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and is an unsubstituted alkoxy group having 1 to 20 carbon atoms. Is more preferably an unsubstituted alkoxy group having 1 to 10 carbon atoms, more preferably an unsubstituted linear alkoxy group having 1 to 4 carbon atoms, and preferably a methoxy group. Further preferred.

  In the triazine derivative represented by the general formula (III), thiophene groups are introduced at the 2nd and 6th positions of the triazine ring. The compound represented by the general formula (III) having such a structure is superior in solubility in an organic solvent as compared with a compound in which a thiophene group is introduced at the 2-position, 4-position, and 6-position of the triazine ring, and is a coating method. This is useful in the manufacture of electronic components by such as.

Among the triazine derivatives represented by the general formula (III), when R ¹ is an alkyl group having 1 to 12 carbon atoms, it is further excellent in solubility in an organic solvent.
In the triazine derivative represented by the general formula (III), a phenyl group is substituted on the thiophene ring. By setting it as such a structure, it is excellent in hole transport property.

  As specific examples of the nitrogen-containing heterocyclic compound represented by the general formula (I), specific examples of the pyrazine derivative represented by the general formula (II) are shown in Table 1 below, and the triazidine derivative represented by the general formula (III) Specific examples are shown in Table 2 below. The present invention is not limited to the following specific examples.

<Organic semiconductor transistor>
The organic semiconductor transistor of this embodiment includes a plurality of electrodes and an organic semiconductor layer containing at least one compound represented by the general formula (I). Other configurations are not particularly limited as long as they correspond to this configuration.
Hereinafter, although it demonstrates in detail, referring a figure, it is not limited to this.

  1, 2, 3 and 4 are cross-sectional views illustrating the configuration of an example of the organic semiconductor transistor of the present embodiment. Here, FIG. 1, FIG. 2 and FIG. 3 show a field effect transistor organic semiconductor transistor. FIG. 4 shows an organic semiconductor transistor of a static induction type (Static Induction Transitor).

The field effect organic semiconductor transistor shown in FIGS. 1, 2, and 3 includes a source electrode 2 and a drain electrode 3 that are spaced apart from each other, and an organic semiconductor layer 4 that is in contact with both the source electrode 2 and the drain electrode 3. A gate electrode 5 spaced from both the source electrode 2 and the drain electrode 3, and an insulating layer 6 provided between the organic semiconductor layer 4 and the gate electrode 5.
A field-effect organic semiconductor transistor is a form of a transistor that is widely used at present, and has advantages such as high-speed switching operation, simplicity of a manufacturing method, and suitability for high integration.

  The field effect organic semiconductor transistor shown in FIGS. 1, 2 and 3 controls the current flowing from the source electrode 2 to the drain electrode 3 by the voltage applied to the gate electrode 5.

  The organic semiconductor transistor shown in FIG. 1 includes a gate electrode 5 on a substrate 1 and further includes an insulating layer 6 on the gate electrode 5. On the insulating layer 6, a source electrode 2 and a drain electrode 3 formed separately are provided. The insulating layer 6 exposed from the source electrode 2 and the drain electrode 3 is covered with the organic semiconductor layer 4.

  In the organic semiconductor transistor shown in FIG. 2, either the source electrode 2 or the drain electrode 3 is formed on the insulating layer 6, and covers the source electrode 2 or the drain electrode 3 and the insulating layer 6 formed on the insulating layer 6. Thus, the organic semiconductor layer 4 is formed, and either the source electrode 2 or the drain electrode 3 that is not formed is formed on the organic semiconductor layer 4 so as to sandwich the organic semiconductor layer 4.

  In the organic semiconductor transistor shown in FIG. 3, the organic semiconductor layer 4 is formed on the insulating layer 6, and the source electrode 2 and the drain electrode 3 are formed on the organic semiconductor layer so as to be separated from each other.

  The static induction transistor (Static Induction Transitor) shown in FIG. 4 includes a source electrode 2 and a drain electrode 3 provided in opposition, an organic semiconductor layer 4 in contact with both the source electrode 2 and the drain electrode 3, and a source And a gate electrode 5 spaced from both the electrode 2 and the drain electrode 3. That is, the source electrode 2, the organic semiconductor layer 4, and the drain electrode 3 are provided in this order on the substrate 1, and a plurality of gate electrodes 5 are provided in the organic semiconductor layer 4. The gate electrode 5 is arranged so as to be parallel to both the source electrode 2 and the drain electrode 3 in the direction from the front to the back of the page, and the gate electrodes 5 are also provided so as to be parallel to each other. Yes.

  In the organic semiconductor transistor element shown in FIGS. 1, 2, 3 and 4, the current flowing from the source electrode 2 to the drain electrode 3 is controlled by the voltage applied to the gate electrode 5.

  The material used for each electrode is a material for injecting charges efficiently, and metals, metal oxides, conductive polymers, carbon, graphite, and the like are used.

  Examples of the metal used for the electrode include magnesium, aluminum, gold, silver, copper, platinum, chromium, tantalum, indium, palladium, lithium, calcium, and alloys thereof. Examples of the metal oxide include metal oxide films such as lithium oxide, magnesium oxide, aluminum oxide, indium tin oxide (ITO), zinc oxide, indium oxide, zinc tin indium oxide, and tin oxide (NESA).

  Examples of the conductive polymer used for the electrode include polyaniline, polythiophene, polythiophene derivatives, polypyrrole, polypyridine, and a complex of polyethylenedioxythiophene and polystyrenesulfonic acid.

Note that in this embodiment mode, conductivity means that the volume resistivity is in the range of 10 ⁷ Ωcm or less. On the other hand, insulating means that the volume resistivity is in the range of 10 ¹⁴ Ωcm or more. A semiconductor means that the volume resistivity is in the range of more than 10 ⁷ Ωcm and less than 10 ¹⁴ Ωcm.

  The volume resistivity is measured in accordance with JIS-K-6911 (1995) by using a circular electrode (high probe IP UR probe made by Mitsubishi Yuka Co., Ltd .: cylindrical electrode outer diameter Φ16 mm, ring electrode part) Is measured by using a microammeter R8340A manufactured by Advantest and applying a voltage of 100V under an environment of 22 ° C / 55% RH and applying a voltage of 5 sec after application. Thus, the volume resistivity is obtained from the volume resistance.

The difference between the ionization potential of the material used for the drain electrode 3 and the source electrode 2 and the ionization potential of the compound represented by the general formula (I) used for the organic semiconductor layer 4 is within 1.0 eV from the viewpoint of charge injection characteristics. It is preferable that it is within 0.5 ev.
Considering the difference in ionization potential between these electrodes and the compound represented by the general formula (I), it is preferable to use Au as the electrode material.

  When a conductive substrate is used, for example, a highly doped silicon substrate may serve as the gate electrode.

  As a method for forming an electrode, a thin film is formed from the above raw material by a method such as vapor deposition or sputtering, and the thin film is formed by a known photolithography method or a lift-off method, a method of thermally transferring aluminum or the like, an ink jet, or the like. There is a method of forming a resist layer and etching the resist layer. Alternatively, the conductive polymer may be dissolved in a solvent, and this solution may be patterned by ink jet or the like.

  The film thicknesses of the source electrode 2 and the drain electrode 3 are not particularly limited, but are generally preferably in the range of several nm to several hundred μm, more preferably 1 nm to 100 μm, and even more preferably. Is 10 nm or more and 10 μm or less.

  In general, the distance (channel length) from the source electrode 2 to the drain electrode 3 is preferably in the range of several hundred nm to several mm, and more preferably 1 μm to 1 mm.

  Examples of the insulating layer 6 include inorganic substances such as silicon dioxide, silicon nitride, tantalum oxide, aluminum oxide, titanium oxide, tantalum oxide, tin oxide, vanadium oxide, barium strontium titanate, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, Polyvinyl chloride resin, cellulose resin, urethane resin, epoxy resin, polystyrene styrene resin, polyvinyl acetate resin, styrene butadiene copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicon Examples thereof include organic insulating polymers such as resins, but are not limited thereto.

Examples of the method for forming an inorganic insulating layer include dry processes such as vacuum deposition, molecular beam epitaxy, ion cluster beam, low energy beam, ion plating, CVD, sputtering, and atmospheric pressure plasma. Furthermore, examples include wet processes such as spray coating, spin coating, blade coating, dip coating, casting, roll coating, bar coating, die coating, air knife, and inkjet. Depending on the material used and the characteristics of the element, it can be selected and employed.
The wet process is preferably used as the method for forming the insulating layer using the organic insulating polymer.

  The film thickness of the insulating layer 6 is not particularly limited, but it is generally preferably in the range of several nm to several hundred μm, more preferably 1 nm to 100 μm, and even more preferably 10 nm. It is 10 μm or less.

  In addition, the interface of the insulating layer 6 in contact with the organic semiconductor layer 4 may be treated with a silane compound such as hexamethyldisilazane, octadecyltrimethoxysilane, octadecyltrichlorosilane, octyltrichlorosilane, or the like. May be rubbed.

  As the substrate 1, silicon single crystal or glass doped with phosphorus or the like at high concentration, glass, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, cellulose resin, urethane resin, epoxy resin, police styrene resin, polyvinyl Examples include, but are not limited to, acetate resins, styrene butadiene copolymers, vinyl chloride-acrylonitrile copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, plastic substrates such as silicone resins, and the like. .

  In particular, when the organic semiconductor transistor of this embodiment is used in an electronic circuit used in electronic paper or digital paper or a portable electronic device, it is desirable to use a flexible substrate as the substrate 1. In particular, by using a substrate having a flexural modulus of 1000 MPa or more, a flexible display element drive circuit or electronic circuit is manufactured.

  As a method for forming the organic semiconductor layer 4, various printing methods using a wet process such as a spin coating method, a casting method, a dip coating method, a die coating method, a roll coating method, a bar coating method, and an ink jet method are used.

  As described above, the compounds represented by the general formulas (I), (II), and (III) exhibit excellent solubility in organic solvents. Therefore, the organic semiconductor layer 4 is formed using a solution in which these compounds are dissolved. The wet process to be formed is suitable as a method for forming an organic semiconductor containing the compounds represented by the general formulas (I), (II) and (III).

  Examples of the solvent for the coating solution include alcohols such as water, methanol, ethanol, isopropyl alcohol, and butanol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexane non, ester solvents such as ethyl acetate and butyl acetate, Hexane, octane, toluene, xylene, ethylbenzene, hydrocarbon solvents such as engineering surfaces, halogenated hydrocarbon solvents such as dichloromethane, chloroform, dichloroethane, tetrachloroethylene, chlorobenzene, o-dichlorobenzene, trichlorobenzene, acetonitrile, propionitrile, Nitrile solvents such as methoxyacetonitrile, glutarodinitrile, benzonitrile, dimethyl sulfoxide, sulfolane, N, N-dimethylformamide, Examples include, but are not limited to, aprotic polar solvents such as N, N-dimethylacetamide and N-methyl-2-pyrrolidone. These solvents may be used alone or in combination of two or more.

  The film thickness of the organic semiconductor layer 4 is not particularly limited, but is generally in the range of several nm to several hundred μm, more preferably 1 nm to 100 μm, and even more preferably 5 nm to 10 μm. It is.

  Further, the organic semiconductor layer 4 may be doped. In addition, both a donor-type dopant and an acceptor-type dopant can be used as the dopatont.

  As the donor dopant, any compound having a function of donating electrons to the organic compound of the organic semiconductor layer 4 is 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, Eu, Gd, Examples thereof include rare earth metals such as Tb, Dy, Ho, Er, and Yb, and ammonium ions.

As the acceptor dopant, any compound having a function of removing electrons from the organic compound of the organic semiconductor layer 4 is preferably used. Examples of the acceptor dopant include halogen compounds such as Cl ₂ , Br ₂ , I ₂ , ICl, ICl ₃ and IBr, Lewis acids such as PF ₅ , AsF ₅ , SbF ₅ , BF ₃ and SO ₃ , HF and HCl. , Proton acids such as HNO ₃ and H ₂ SO ₄ , organic acids such as acetic acid, formic acid and amino acids, transition metal compounds such as FeCl ₃ , TiCl ₄ and HfCl ₄ , Cl ⁻ , Br ⁻ , I ⁻ , ClO ₄ −, Electrolyte anions such as sulfonate anion, tetracyanoethylene, 7,7,8,8-tetracyanoquinodimethane, 11,11,12,12-tetracyanonaphth-2,6-quinodimethane, 2,5-difluoro- Examples of organic compounds include 7,7,8,8-tetracyanoquinodimethane and tetrafluorotetracyanoquinodimethane. That.

Further, a protective layer may be provided in order to prevent deterioration of the organic semiconductor transistor due to moisture or oxygen. Specific examples of the protective layer material include metals such as In, Sn, Pb, Au, Cu, Ag, and Al, metal oxides such as MgO, SiO ₂ , and TiO ₂ , polyethylene resins, polyurea resins, and polyimide resins. A vacuum deposition method, a sputtering method, a plasma polymerization method, a CVD method, and a coating method are applied to the formation of the protective layer including a resin.

In the organic semiconductor transistor of this embodiment, the compound represented by the general formula (I) is used for the organic semiconductor layer. The compound represented by the general formula (I) exhibits excellent solubility in an organic solvent generally used in the production of electronic devices. Therefore, when the compound represented by the general formula (I) is applied to the organic semiconductor layer, the organic semiconductor layer can be manufactured by a wet process. As a result, the organic semiconductor layer can be formed with an inexpensive apparatus as compared with a layer forming method such as sputtering, and the area of the device can be easily increased.
Furthermore, the organic semiconductor layer containing the general formula (I) is provided with an organic semiconductor transistor that is excellent in charge transport capability and can suppress a decrease in charge mobility.

  When an electronic device using the organic semiconductor transistor of this embodiment is manufactured, it can be used as a configuration (semiconductor device) in which one or more organic semiconductor transistors of this embodiment are mounted on a substrate. A desired electronic device is manufactured by further combining other elements, circuits, and the like with this semiconductor device.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.
For identification of the target product, ¹ H-NMR spectrum ( ¹ H-NMR, solvent: CDCl ₃ , Varian Inc., UNITY-300, 300 MHz) and IR spectrum (Fourier transform infrared by KBr tablet method). A spectrophotometer (Horiba, Ltd., FT-730, resolution: 4 cm ⁻¹ )) was used.

[Synthesis Example 1]
(Synthesis of Compound (II-6))
2,6-dichloropyrazine (Tokyo Chemical Industry Co., Ltd.) 4.0 g (27 mmol), 2-thiopheneboronic acid (Tokyo Chemical Industry Co., Ltd.) 7.5 g (59 mmol), and tetrakis (triphenylphosphine) 0.43 g (0.37 mmol) of palladium (0) (hereinafter sometimes referred to as Pd (PPh ₃ ) ₄ ) (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 150 ml of tetrahydrofuran, and sodium carbonate (Wako Pure Chemical Industries, Ltd.) was dissolved. A solution prepared by dissolving 14.5 g of Kogyo Co., Ltd. in 60 ml of water was added, and the mixture was stirred at 60 ° C. for 6 hours under a nitrogen stream.
After allowing to cool, the mixture is poured into 500 ml of water, and the deposited precipitate is collected by filtration, washed with water, dried under reduced pressure, dissolved in toluene, impurities are removed by column chromatography (silica gel), and a toluene / methanol mixed solvent. Further recrystallization gave 3.3 g of 2,6-bis (2′-thienyl) pyrazine (50% of the theoretical yield).

3.0 g (12 mmol) of 2,6-bis (2′-thienyl) pyrazine obtained above is dissolved in 80 ml of N, N-dimethylformamide, and N-bromosuccinimide (hereinafter sometimes referred to as NBS) ( 5.5 g (31 mmol) manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at 80 ° C. for 5 hours under a nitrogen stream.
After allowing to cool, the mixture was poured into 500 ml of water, and the deposited precipitate was collected by filtration, washed with water, dried under reduced pressure, recrystallized from a toluene / methanol mixed solvent, and 2,6-bis (5′-bromo- 2.45 g (49% of theoretical yield) of 2′-thienyl) pyrazine were obtained.

  0.52 g (1.3 mmol) of 2,6-bis (5′-bromo-2′-thienyl) pyrazine obtained above, 4-n-butylbenzeneboronic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 0 0.15 g (2.9 mmol) and 0.017 g (0.015 mmol) of tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in 25 ml of N-methylpyrrolidone, and sodium carbonate (Japanese A solution prepared by dissolving 0.80 g (6.8 mmol) manufactured by Kojun Pharmaceutical Co., Ltd. in 5 ml of water was added and stirred for 6 hours.

After allowing to cool, the mixture was poured into 400 ml of water, and the deposited precipitate was collected by filtration and washed with water. This was dried under reduced pressure, dissolved in toluene, purified by column chromatography (silica gel), and recrystallized from a toluene / methanol mixed solvent to obtain 0.45 g of compound (II-6) (69% of the theoretical yield). Obtained.
The melting point of the obtained compound (II-6) was 152 ° C. to 152.5 ° C.
Moreover, the obtained compound (II-6) was identified by infrared absorption measurement and ¹ H-NMR.

[Synthesis Example 2]
(Synthesis of Compound (II-11))
3.8 g (9.4 mmol) of 2,6-bis (5′-bromo-2′-thienyl) pyrazine obtained in the same manner as compound (II-6), 2-thiopheneboronic acid (Tokyo Chemical Industry Co., Ltd.) )) 2.7 g (21 mmol) and tetrakis (triphenylphosphine) palladium (0) (Tokyo Chemical Industry Co., Ltd.) 0.18 g (0.16 mmol) were dissolved in 200 ml of N, N-dimethylformamide. A solution prepared by dissolving 5.7 g (48 mmol) of sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) in 30 ml of water was added, and the mixture was stirred at 90 to 100 ° C. for 4 hours.
After standing to cool, the mixture was poured into 700 ml of water, and the deposited precipitate was collected by filtration, washed with water, dried under reduced pressure, dissolved in toluene, and purified by column chromatography (silica gel). Further recrystallization gave 1.8 g (47% of theoretical yield) of 2,6-bis (2 ′, 2 ″ -bithienyl) pyrazine.

  1.36 g (12 mmol) of 2,6-bis (2 ′, 2 ″ -bithiophen-5′-yl) pyrazine obtained above was dissolved in 80 ml of N, N-dimethylformamide, and N-bromosuccinimide (sum) 1.33 g (31 mmol) manufactured by Kojun Pharmaceutical Co., Ltd. was added, and the mixture was stirred at 70 ° C. for 5 hours under a nitrogen stream. After allowing to cool, the mixture was poured into 500 ml of water, and the deposited precipitate was collected by filtration and washed with water. This was dried under reduced pressure and recrystallized from a toluene / methanol mixed solvent to obtain 1.43 g of 2,6-bis (5 ″ -bromo-2 ′, 2 ″ -bithiophen-5′-yl) pyrazine (theoretical yield). 76%).

  1.0 g (0.18 mmol) of 2,6-bis (5 ″ -bromo-2 ′, 2 ″ -bithiophen-5′-yl) pyrazine obtained above, 4-n-octylbenzeneboronic acid ( Tokyo Chemical Industry Co., Ltd. (1.0 g, 0.44 mmol) and tetrakis (triphenylphosphine) palladium (0) 0.076 g (0.066 mmol) were dissolved in 200 ml of N-methylpyrrolidone, and sodium carbonate (Japanese A solution prepared by dissolving 1.4 g (1.2 mmol) (manufactured by Kojun Pharmaceutical Co., Ltd.) in 5 ml of water was added, and the mixture was stirred at 100 ° C. for 6 hours in a nitrogen stream.

After allowing to cool, the mixture is poured into 800 ml of water, and the deposited precipitate is collected by filtration, washed with water, dried under reduced pressure, dissolved in toluene, purified by column chromatography (silica gel), and recrystallized from toluene. Thus, 0.23 g (16% of the theoretical yield) of the compound (II-11) was obtained. The melting point of the obtained compound (II-11) was 197.5 ° C. to 199 ° C.
The obtained compound (II-11) was identified by infrared absorption measurement and ¹ H-NMR.

[Synthesis Example 3]
(Synthesis of Compound (III-7))
2,4-dichloro-6-methoxy-1,3,5-triazine (Sigma-Aldrich) 4.0 g (22 mmol), 2-thiopheneboronic acid (Tokyo Chemical Industry Co., Ltd.) 6.2 g (48 mmol) ) And tetrakis (triphenylphosphine) palladium (0) 0.10 g (0.09 mmol) are dissolved in 160 ml of tetrahydrofuran, and 12.3 g of sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) is dissolved in 50 ml of water. And stirred at 60 ° C. for 6 hours under a nitrogen stream.

  After allowing to cool, the mixture was poured into 800 ml of water, and the oil-soluble content was extracted with ethyl acetate. After concentration under reduced pressure, impurities were removed by column chromatography (silica gel), and recrystallization from a toluene / methanol mixed solvent gave 2,4-bis (2′-thienyl) -6-methoxy-1,3, 4.55 g of 5-triazine (74% of theoretical yield) was obtained.

4.0 g (9.6 mmol) of 2,4-bis (2′-thienyl) -6-methoxy-1,3,5-triazine obtained above was dissolved in 50 ml of N, N-dimethylformamide, and N— Bromosuccinimide (Wako Pure Chemical Industries, Ltd.) 6.2g (35mmol) was added, and it stirred at 80 degreeC under nitrogen stream for 5 hours.
After allowing to cool, the mixture was poured into 800 ml of water, and the deposited precipitate was collected by filtration and washed with water. This was dried under reduced pressure and recrystallized from a toluene / methanol mixed solvent to give 2.45 g of 2,4-bis (5′-bromo-2′-thienyl) -6-methoxy-1,3,5-triazine (theoretical). 49% of the yield) was obtained.

2,4-bis (5′-bromo-2′-thienyl) -6-methoxy-1,3,5-triazine 1.03 g (1.3 mmol) obtained above, 4-n-butylbenzeneboronic acid 1.0 g (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.021 g (0.018 mmol) tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry Co., Ltd.) are dissolved in 60 ml of N-methylpyrrolidone. A solution prepared by dissolving 3.0 g (6.8 mmol) of sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) in 15 ml of water was added, and the mixture was stirred at 90 ° C. for 6 hours in a nitrogen stream.
After allowing to cool, the mixture is poured into 400 ml of water, and the deposited precipitate is collected by filtration, washed with water, dried under reduced pressure, dissolved in toluene, purified by column chromatography (silica gel), and a toluene / methanol mixed solvent. Recrystallization gave 0.80 g (62% of the theoretical yield) of compound (III-7). The melting point of the obtained compound (III-7) was 140 ° C. to 141 ° C.
The obtained compound (III-7) was identified by infrared absorption measurement and ¹ H-NMR.

[Synthesis Example 4]
(Synthesis of Compound (III-11))
2,4-bis (5′-bromo-2′-thienyl) -6-methoxy-1,3,5-triazine 1.1 g (2.6 mmol) obtained from compound (III-7), 2-thiophene Boronic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 1.0 g (8.0 mmol) and tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.04 g (0.035 mmol) -A solution in which 3.0 g (6.8 mmol) of sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 15 ml of water was added and dissolved in 40 ml of methylpyrrolidone, followed by stirring at 80 ° C for 4 hours in a nitrogen stream.
After allowing to cool, the mixture was poured into 400 ml of water, and the deposited precipitate was collected by filtration and washed with water. This was dried under reduced pressure, dissolved in toluene, purified by column chromatography (silica gel), recrystallized from a toluene / methanol mixed solvent, and 2,4-bis (2 ′, 2 ″ -bithiophene-5 ′). -Il) -6-methoxy-1,3,5-triazine 0.78 g (71% of the theoretical yield) was obtained.

0.76 g (1.8 mmol) of 2,4-bis (2 ′, 2 ″ -bithiophen-5′-yl) -6-methoxy-1,3,5-triazine obtained above was added to N, N— After dissolving in 35 ml of dimethylformamide, 0.68 g (3.8 mmol) of N-bromosuccinimide (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was stirred at 70 ° C. for 3 hours under a nitrogen stream.
After allowing to cool, the mixture was poured into 400 ml of water, and the deposited precipitate was collected by filtration and washed with water. This was dried under reduced pressure and recrystallized from a toluene / methanol mixed solvent to give 2,4-bis (5 ″ -bromo-2 ′, 2 ″ -bithiophen-5′-yl) -6-methoxy-1, 0.71 g of 3,5-triazine (68% of the theoretical yield) was obtained.

0.65 g (1.1 mmol) of 2,4-bis (5 ″ -bromo-2 ′, 2 ″ -bithiophen-5′-yl) -6-methoxy-1,3,5-triazine obtained above ), 4-n-butylbenzeneboronic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 0.45 g (2.5 mmol), and tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry Co., Ltd.) 0 .014 g (0.012 mmol) is dissolved in 80 ml of N-methylpyrrolidone, and a solution obtained by dissolving 0.61 g (5.2 mmol) of sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) in 4 ml of water is added at 90 ° C. Stir for 6 hours.
After allowing to cool, the mixture is poured into 500 ml, and the deposited precipitate is collected by filtration, washed with water, dried under reduced pressure, dissolved in toluene, purified by column chromatography (silica gel), and recrystallized from toluene. Compound (III-11) 0.22 g (30% of the theoretical yield) was obtained. The melting point of the obtained compound (III-11) was 171 ° C. to 173 ° C.
The obtained compound (III-11) was identified by infrared absorption spectrum measurement and ¹ H-NMR spectrum.

[Synthesis Example 5]
(Synthesis of Compound (II-17))
0.52 g (1.3 mmol) of 2,6-bis (5′-bromo-2′-thienyl) pyrazine obtained from compound (II-6), 0.48 g of 4-ethoxyphenylboronic acid (manufactured by Aldrich) 2.9 mmol) and 0.017 g (0.015 mmol) of tetrakis (triphenylphosphine) palladium (0) (manufactured by Tokyo Chemical Industry Co., Ltd.) are dissolved in 25 ml of N-methylpyrrolidone, and sodium carbonate (Wako Pure Chemical Industries, Ltd.) is dissolved. A solution prepared by dissolving 0.80 g (6.8 mmol) in 5 ml of water was added and stirred for 8 hours.

After allowing to cool, the mixture was poured into 400 ml of water, and the deposited precipitate was collected by filtration and washed with water. This was dried under reduced pressure, dissolved in toluene, purified by column chromatography (silica gel), and recrystallized from a toluene / methanol mixed solvent to obtain 0.38 g of compound (II-17) (60% of the theoretical yield). Obtained.
The melting point of the obtained compound (II-17) was 165 ° C. to 167 ° C.
The obtained compound (II-17) was identified by infrared absorption measurement and ¹ H-NMR.

[Example 1]
A silicon substrate having an electrical resistivity of 0.007 Ω · cm also served as a gate electrode, and a thermal SiO ₂ film having a thickness of 200 nm was formed thereon as an insulating film.
Next, ultrasonic cleaning for 5 minutes in acetone for electronic industry, ultrasonic cleaning for 5 minutes in 2-propanol for electronic industry, and drying with dry nitrogen, followed by UV-ozone irradiation for 15 minutes for cleaning. Then, after being immersed in 1,1,1,3,3,3-hexamethyldisilazane (manufactured by Aldrich) for 1 hour, it was subjected to ultrasonic cleaning with electronics industry toluene for 2 minutes and dried with dry nitrogen.

Compound (II-6) was dissolved at 0.6% by mass in toluene for electronic industry, and this solution was applied onto the washed silicon group by a spin coat method (20 seconds at 2000 rpm), followed by natural drying. An organic semiconductor layer was formed by heating at 100 ° C. for 1 minute in a nitrogen atmosphere.
On top of that, Au was deposited in a thickness of 60 nm by vacuum deposition (vacuum degree: 2 × 10 ⁻⁴ Pa) using a metal mask to form a source electrode and a drain electrode, and an organic semiconductor transistor was fabricated. The channel width was 1.5 mm and the channel length was 50 μm.
The organic semiconductor transistor fabricated as described above exhibited characteristics as a p-type transistor.

<Measurement of charge mobility>
The obtained organic semiconductor transistor obtained the charge mobility from the saturation region of the current-voltage characteristics. Furthermore, it preserve | saved at 25 degreeC, The transistor characteristic was evaluated again after one month progress, and the charge mobility was evaluated. The results are shown in Table 3.

[Examples 2 to 5]
In Example 1, when forming the organic semiconductor layer, the compound (II-11), (III-7), (III-11), or (II-17) is used instead of the compound (II-6). An organic semiconductor transistor was produced in the same manner as in Example 1 except that. The obtained organic semiconductor transistor was evaluated in the same manner as in Example 1.

[Comparative Examples 1 and 2]
In Example 1, instead of the compound (II-6), 13,6-N-sulfinylacetamidopentacene (Aldrich) was used and the heating temperature was changed to 160 ° C. An organic semiconductor transistor was manufactured as Comparative Example 1.

  Further, the same as Comparative Example 1 except that poly (3-hexylthiophene) (manufactured by Aldrich) was used instead of 13,6-N-sulfinylacetamidopentacene used in Comparative Example 1 and the solvent was changed to chloroform. The organic semiconductor transistor was manufactured as Comparative Example 2.

  The organic semiconductor transistors of Comparative Examples 1 and 2 were evaluated in the same manner as in Example 1. The results are shown in Table 3.

  From the above Table 3, the organic semiconductor transistors of Examples 1 to 5 have a higher charge mobility immediately after production than the organic semiconductor transistors of Comparative Examples 1 and 2, and stable charge mobility even after one month of production. It can be seen that

1 substrate 2 source electrode 3 drain electrode 4 organic semiconductor layer 5 gate electrode 6 insulating layer

Claims (6)

A plurality of electrodes;
An organic semiconductor layer containing at least one compound represented by the following general formula (I);
An organic semiconductor transistor comprising:

[In the general formula (I), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms; It represents a heterocyclic residue containing at least one nitrogen atom for forming an aromatic hetero 6-membered ring, and n represents an integer of 1 or more and 3 or less. ] The organic semiconductor transistor according to claim 1, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (III).

[In the general formula (III), R ¹ represents a hydrogen atom, 1 or more carbon atoms substituted or unsubstituted 20 an alkyl group, or a substituted or unsubstituted C 1 to 20 alkoxy group carbon, R ² Is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, or It represents a substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms, and n represents an integer of 1 to 3. ] The organic semiconductor transistor according to claim 1, wherein the compound represented by the general formula (I) is a compound represented by the following general formula (II).

[In General Formula (II), R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, and n is Represents an integer of 1 to 3. ] The organic semiconductor transistor according to claim ^1, wherein R ¹ is an unsubstituted linear alkyl group having 4 to 8 carbon atoms. The plurality of electrodes are a source electrode, a drain electrode and a gate electrode;
Furthermore, an insulating layer is provided,
The gate electrode is provided apart from both the source electrode and the drain electrode;
The organic semiconductor layer is provided in contact with both the source electrode and the drain electrode,
The insulating layer is provided between the organic semiconductor layer and the gate electrode,
And the organic-semiconductor transistor of any one of Claims 1-4 which is a field effect type | mold. The plurality of electrodes are a source electrode, a drain electrode and a gate electrode;
The gate electrode is provided apart from both the source electrode and the drain electrode;
The organic semiconductor layer is provided in contact with both the source electrode and the drain electrode,
And the organic-semiconductor transistor of any one of Claims 1-4 which is an electrostatic induction type.

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