JP2015199716A - Polycyclic fused ring compound, organic semiconductor material, organic semiconductor device, and organic transistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycyclic fused ring compound which has sufficiently high carrier mobility and is excellent in storage stability, and to provide an organic semiconductor material, an organic semiconductor device, and an organic transistor containing the compound.SOLUTION: The polycyclic fused ring compound is represented by formula (1), and the organic semiconductor material, the organic semiconductor device, and the organic transistor contain the compound. [Xto Xare each O, S, or Se; and Rto Rare each H, a halogen atom, an alkyl group, a haloalkyl group, an alkoxy group, a haloalkoxy group, an alkylthio group, a haloalkylthio group, an alkylamino group, a dialkylamino group, an alkylsulfonyl group, a haloalkylsulfonyl group, an aryl group, an alkylsilyl group, an alkylsilylethynyl group, or the like.]

Description

  The present invention relates to a polycyclic fused ring compound, and an organic semiconductor material, an organic semiconductor device and an organic transistor using the polycyclic fused ring compound.

  In recent years, organic semiconductor devices such as organic EL devices, organic transistors, and organic thin film photoelectric conversion devices using organic semiconductor materials have attracted attention and have been put into practical use. For example, an organic transistor which is a kind of organic semiconductor device has a gate electrode, an insulator layer, and an organic semiconductor layer arranged in this order on a substrate, and a source electrode formed at a predetermined interval on the organic semiconductor layer, and A drain electrode is arranged. In the organic transistor thus formed, the organic semiconductor layer becomes a channel region, and an on / off operation is performed by controlling a current flowing between the source electrode and the drain electrode by applying a voltage to the gate electrode. .

  Conventionally, a thin film transistor has been manufactured using silicon having an amorphous structure or a polycrystalline structure. However, a CVD apparatus used for manufacturing such a thin film transistor using silicon is very expensive, and an increase in the size of a display device using a thin film transistor is accompanied by a significant increase in manufacturing cost. It was. In addition, since the process of depositing amorphous or polycrystalline silicon is performed at a very high temperature, the types of materials that can be used as a substrate are limited, and thus materials such as lightweight resin substrates cannot be used. There was a problem.

  In order to solve such a problem, an organic transistor using an organic substance as described above has been proposed in place of amorphous or polycrystalline silicon. As a method for forming an organic transistor with an organic material, a film forming method such as a vacuum deposition method or a coating method is known. According to these film formation methods, it is possible to increase the size of the element while suppressing an increase in manufacturing cost, and it is possible to relatively reduce the process temperature required for film formation. For this reason, the organic transistor has an advantage that there are few restrictions on the selection of the material used for the substrate, and its practical use is expected, and research reports have been actively made.

  A practical organic transistor requires high carrier mobility (hereinafter may be abbreviated as mobility), a large current on / off ratio, and excellent storage stability. The on / off ratio here refers to dividing the current flowing between the source and drain when a gate voltage is applied (on) by the current flowing between the source and drain when no gate voltage is applied (off). Value. The on-current is usually a current value (saturation current) when the gate voltage is increased and the current flowing between the source and the drain is saturated.

  As p-type organic semiconductor materials used for organic transistors, compounds such as conjugated polymers, multimers such as thiophene, polycyclic condensed compounds such as metal phthalocyanine compounds and pentacene are known.

  Among the organic semiconductor materials mentioned above, pentacene, which is a polycyclic condensed ring compound, has been attracting attention as a material that exhibits high carrier mobility similar to amorphous silicon due to its π-conjugated system, but it has been actively studied, but it is stored in the atmosphere. The disadvantage of low stability is known.

  Against this background, various polycyclic fused-ring compounds have been studied as materials having storage stability and high carrier mobility. For example, a polycyclic condensed ring compound such as a four-ring polycyclic condensed compound obtained by condensing two thiophene rings on a naphthalene ring and a five-ring polycyclic condensed compound obtained by condensing two thiophene rings on an anthracene ring has been proposed. Yes.

  Patent Document 1 discloses that the latter polycyclic fused ring compound is useful as a material for an organic semiconductor layer of an organic transistor.

  Patent Document 2 discloses that a polycyclic fused ring compound obtained by condensing benzothiophene to a naphthalene ring (Exemplary Compound No. 125 of Patent Document 2) is useful as a material for an organic semiconductor layer of an organic transistor. Has been.

  Furthermore, Non-Patent Document 1 discloses a polycyclic fused-ring compound having a high carrier mobility (BBTBDT such as Figure 1 of Non-Patent Document 1).

JP-A-11-195790 JP 2009-267134 A

Tatsuya Yamamoto, et al., 5 others, “Larly π-Extended Thienoacenes: Synthesis, Characterization, and Application to Organic Field Effect Transistors: Large π-expanded Thienoacene with a Thieno [3,2-b] thiophene Structure Inside with Internal Thieno [3,2-b] thiopehne Substructures: Synthesis, Characterization, and Organic Field-Effect Transictor Applications (S), United States, Organic Letters (US), Organic Letters. Month 09 , Vol. 14, no. 18, p. 4914-4917

  As described above, for example, when used as an organic device, a compound having not only a sufficiently high carrier mobility in practical use but also excellent properties such as high storage stability is required. This invention is made | formed in view of such a situation, and it aims at providing the novel polycyclic fused-ring compound which has the outstanding characteristic. Another object of the present invention is to provide an organic semiconductor material, an organic semiconductor device, and an organic transistor using a polycyclic fused ring compound having excellent characteristics.

  As a result of examining the development of various polycyclic fused ring compounds, the present inventors have expanded the π-conjugated system of the compound by further condensing an aromatic ring to the naphthalene structure, The present invention has been found to be useful as an organic transistor material. That is, the present invention is as follows.

（一般式（１）において、Ｘ₁〜Ｘ₄は、それぞれ独立して酸素原子、硫黄原子又はセレン原子を表し、Ｒ₁〜Ｒ₁₂は、それぞれ独立して、水素原子、ハロゲン原子、置換若しくは無置換の炭素数１〜３０のハロアルキル基、置換若しくは無置換の炭素数１〜３０のハロアルキル基、置換若しくは無置換の炭素数１〜３０のアルコキシ基、置換若しくは無置換の炭素数１〜３０のハロアルコキシ基、置換若しくは無置換の炭素数１〜３０のアルキルチオ基、置換若しくは無置換の炭素数１〜３０のハロアルキルチオ基、置換若しくは無置換の炭素数１〜３０のアルキルアミノ基、置換若しくは無置換の炭素数２〜６０のジアルキルアミノ基（アルキル基は互いに結合して窒素原子を含む環状構造を形成してもよい）、置換若しくは無置換の炭素数１〜３０のアルキルスルホニル基、置換若しくは無置換の炭素数１〜３０のハロアルキルスルホニル基、置換若しくは無置換の炭素数３〜６０のアリール基、置換若しくは無置換の炭素数３〜２０のアルキルシリル基、置換若しくは無置換の炭素数５〜６０のアルキルシリルエチニル基、置換若しくは無置換の炭素数３〜６０のアリールアミノ基、置換若しくは無置換の炭素数６〜１２０のジアリールアミノ基又はシアノ基を表す。）で表されることを特徴とする。 The polycyclic fused ring compound according to the present invention has the general formula (1)

(In General Formula (1), X < ₁ > -X < ₄ > represents an oxygen atom, a sulfur atom, or a selenium atom each independently, and R < ₁ > -R < ₁₂ > is respectively independently a hydrogen atom, a halogen atom, substitution, or An unsubstituted haloalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted haloalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted carbon number 1 to 30 Haloalkoxy group, substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, substituted or unsubstituted haloalkylthio group having 1 to 30 carbon atoms, substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, substituted Or an unsubstituted dialkylamino group having 2 to 60 carbon atoms (the alkyl groups may be bonded to each other to form a cyclic structure containing a nitrogen atom), substituted or unsubstituted carbon An alkylsulfonyl group having 1 to 30 carbon atoms, a substituted or unsubstituted haloalkylsulfonyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 3 to 60 carbon atoms, and a substituted or unsubstituted alkyl group having 3 to 20 carbon atoms Silyl group, substituted or unsubstituted alkylsilylethynyl group having 5 to 60 carbon atoms, substituted or unsubstituted arylamino group having 3 to 60 carbon atoms, substituted or unsubstituted diarylamino group having 6 to 120 carbon atoms, or cyano Represents a group).

  In addition, the organic semiconductor material according to the present invention is characterized by containing the above-mentioned polycyclic fused ring compound.

  Furthermore, the organic semiconductor device according to the present invention has a thin film formed using the above-described organic semiconductor material.

  Furthermore, the organic transistor according to the present invention includes a substrate, a gate electrode disposed on the substrate, a source electrode and a drain electrode spaced apart on the substrate, the gate electrode, the source electrode, and the drain. And an organic semiconductor layer in contact with the source electrode and the drain electrode, wherein the organic semiconductor layer is formed using the organic semiconductor material described above. And

  The polycyclic fused ring compound, the organic semiconductor material, the organic semiconductor device, and the organic transistor according to the present invention are novel substances that have excellent effects such as having sufficiently high carrier mobility in practical use.

It is the schematic which shows the example of an aspect of the organic transistor which concerns on this invention. It is the schematic which shows the process for manufacturing the example of 1 aspect of the organic transistor which concerns on this invention. It is a graph which shows the ultraviolet visible absorption spectrum of the thin film of the polycyclic fused-ring compound which concerns on this invention. It is a graph which shows the semiconductor characteristic of the organic transistor which concerns on this invention. It is a graph which shows the semiconductor characteristic of the organic transistor which concerns on this invention. It is a graph which shows the semiconductor characteristic of the organic transistor which concerns on this invention.

  The present invention is described in detail below.

<Polycyclic fused ring compound represented by the general formula (1)>
The polycyclic fused ring compound according to the present invention is represented by the following general formula (1).

In the general formula _(1), X 1 ~X ₄ each independently represent an oxygen atom, a sulfur atom or a selenium atom. R _{1 to} R ₁₂ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 30 carbon atoms, a haloalkyl group having 1 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, or an alkyl group having 1 to 30 carbon atoms. A haloalkoxy group having 1 to 30 carbon atoms, a haloalkylthio group having 1 to 30 carbon atoms, an alkylamino group having 1 to 30 carbon atoms, and a dialkylamino group having 2 to 60 carbon atoms (the alkyl groups are bonded to each other). Or a cyclic structure containing a nitrogen atom), an alkylsulfonyl group having 1 to 30 carbon atoms, a haloalkylsulfonyl group having 1 to 30 carbon atoms, an aryl group having 3 to 60 carbon atoms, or an alkyl group having 3 to 20 carbon atoms. An alkylsilyl group, an alkylsilylethynyl group having 5 to 60 carbon atoms, an arylamino group having 3 to 60 carbon atoms, a diarylamino group having 6 to 120 carbon atoms, or a cyano group. Group may have a substituent.

In the general formula (1), from the viewpoint of mobility, at least one of X ₁ and X ₂ and at least one of X ₃ and X ₄ are preferably sulfur atoms (S). More preferably, X < ₁ > -X < ₄ > is a sulfur atom. By the X ₁ to X ₄ and the sulfur atom, for example, in the case of producing an organic transistor using the compound, improve the stability of the product can be expected.

  In the above general formula (1), those having substituents can be applied to a solution process in which the organic semiconductor layer is formed by dissolving the polycyclic fused ring compound according to the present invention in a solvent. It is preferable at this point, and it is more preferable in it being a linear substituent.

Hereinafter, the specific example of each group which R < ₁ > -R < ₁₂ > of General formula (1) shows is demonstrated.

  The position, number, and type of substituents are not particularly limited, but can be substituted in the range of 0 to 12 per molecule of the polycyclic fused ring compound represented by the general formula (1). In the case where two or more substituents are substituted, two or more kinds of substituents can be mixed.

  The alkyl group is a saturated or unsaturated linear, branched or cyclic aliphatic hydrocarbon group. Carbon number of an alkyl group becomes like this. Preferably it is 1-30, More preferably, it is 4-15. Here, examples of the saturated linear or branched alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, n Examples include groups such as -hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-dodecyl group, n-stearyl group. Examples of the cyclic alkyl group include groups such as a cyclopentyl group, a cyclohexyl group, an adamantyl group, and a norbornyl group. Examples of the unsaturated alkyl group include a vinyl group, an allyl group, and a 3-butenyl group.

  By using a linear alkyl group as the alkyl group, it is possible to eliminate as much as possible the factors that cause performance degradation such as molecular orientation degradation and crystallinity degradation. Therefore, it can be expected that the possibility of deterioration of transistor characteristics due to such performance deterioration is reduced. In addition, by using a saturated alkyl group as the alkyl group, the reactivity can be suppressed as compared with the case where an unsaturated bond is included, so that it can be expected that deterioration such as oxidation hardly occurs. That is, it is preferable to use a saturated linear alkyl group as the alkyl group.

  However, the use of a branched alkyl group as the alkyl group can be expected to increase the solubility. Furthermore, it can be expected that the shorter the alkyl group, the higher the heat resistance of the device. In addition, the longer the alkyl group, the denser the packing of the crystal due to the interaction of the alkyl chain, and the improvement in mobility can be expected. In this case, an alkyl chain having an appropriate length, for example, an alkyl chain having about 4 to 15 carbon atoms is preferable.

  Examples of the halogen atom include halogen atoms such as fluorine, chlorine, bromine and iodine atoms.

  The haloalkyl group is one in which one to all of the hydrogens on the above-described alkyl group are substituted with halogen atoms. For example, chloromethyl group, 1-chloroethyl group, 2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group, 1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group, 1 , 2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo- t-butyl group, 1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group, 2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group, 1,3-diiodoisopropyl group 2,3-diiodo-t-butyl group, 1,2,3-triiodopropyl group, fluoromethyl group, 1-fluoroethyl group, 2-fluoro Examples include oloethyl group, 2-fluoroisobutyl group, 1,2-difluoroethyl group, difluoromethyl group, trifluoromethyl group, pentafluoroethyl group, perfluoroisopropyl group, perfluorobutyl group, and perfluorocyclohexyl group. .

The alkoxy group is a group represented by —OZ ₁ (Z ₁ is the above-described alkyl group), and examples of Z ₁ include the same examples as the above-described alkyl group. Further, the haloalkoxy group, -OZ ₂ (Z ₂ is above alkyl group) is a group represented by, as an example of Z ₂ include those exemplified the same haloalkyl groups described above.

The alkylthio group is a group represented by —SZ ₁ (Z ₁ is the alkyl group described above), and examples of Z ₁ include the same examples as the alkyl group described above. Further, the haloalkylthio group is a group represented by -SZ _2, examples of Z ₂ include those exemplified the same haloalkyl groups described above.

The alkylamino group is a group represented by —NHZ ₁ (Z ₁ is the alkyl group described above). The dialkylamino group is a group represented by —NZ ₁ Z ₃ (Z ₃ is the alkyl group described above). In these alkylamino groups and dialkylamino groups, examples of Z ₁ and Z ₃ are the same as the above-described alkyl groups. The alkyl group of the dialkylamino group may be bonded to each other to form a ring structure containing a nitrogen atom, and examples of the ring structure include pyrrolidine, piperidine and the like.

The alkylsulfonyl group is a group represented by —SO ₂ Z ₁ (Z ₁ is the alkyl group described above), and examples of Z ₁ include the same examples as the alkyl group described above. The haloalkylsulfonyl group is a group represented by —SO ₂ Z ₂ (Z ₂ is the alkyl group described above), and examples of Z ₂ include the same examples as the haloalkyl group described above.

  The aryl group is an aromatic hydrocarbon ring and an aromatic heterocyclic ring. Examples of the aromatic hydrocarbon ring include benzene, naphthalene, anthracene, chrysene, phenanthrene, tetracene, fluorene, pyrene, fluoranthene, perylene and the like. Examples of aromatic heterocycles include pyridine, pyrazine, indole, acridine, pyrrole, imidazole, pyrazole, quinoline, naphthyridine, quinoxaline, phenazine, phenothiazine, phenoxazine, diazaanthracene, pyridoquinoline, pyrimidoquinazoline, pyrazino. Quinoxaline, phenanthroline, carbazole, thiophene, benzothiophene, dibenzothiophene, benzodithiophene, [1] benzothieno [3,2-b] benzothiophene, thienothiophene, dithienothiophene, furan, benzofuran, dibenzofuran, benzodifuran, thiazole, benzo Thiazole, dithiaindacene, dithiaindenoindene, dibenzoselenophene, diselenindacene, diselenaindenoindene, dibenzosi Lumpur, and the like.

  The substituent that the aryl group may have is not particularly limited, and examples thereof include a halogen atom and an alkyl group. About a halogen atom and an alkyl group, the example similar to what was demonstrated as the above-mentioned halogen atom and alkyl group is mentioned.

  As the aryl group, those based on an aromatic hydrocarbon ring are preferable, and a phenyl group is particularly preferable. From the viewpoint of solubility, a phenyl group substituted with a linear alkyl group having 4 to 15 carbon atoms is preferred.

The alkylsilyl group is a group represented by —SiZ ₁ Z ₃ Z ₄ (Z ₁ , Z ₃ and Z ₄ are the above-described alkyl groups). Examples of Z ₁ , Z ₃ and Z ₄ are the same as the alkyl groups described above. For example, a trimethylsilyl group etc. are mentioned.

  Examples of the alkylsilylethynyl group include a group represented by the above alkylsilyl group via an ethynylene group, and examples thereof include a trimethylsilylethynyl group, a triethylsilylethynyl group, and a triisopropylsilylethynyl group.

The arylamino group is a group represented by —NHZ ₅ (Z ₅ is the above aryl group). The diarylamino group is a group represented by —NZ ₅ Z ₆ (Z ₅ and Z ₆ are the above-described aryl groups). Examples of Z ₅ and Z ₆ are the same as those of the aryl group described above.

  Such an organic semiconductor material containing the polycyclic fused ring compound according to the present invention can be used as an organic transistor. Examples of specific compounds useful when the polycyclic fused ring compound according to the present invention is used as an organic semiconductor material are listed below. However, the polycyclic fused ring compound according to the present invention is not limited to these.

The polycyclic fused ring compound according to the present invention can be realized as various compounds, as exemplified by a part of the above. For example, in the general formula (1), the structural formulas (11) to (11) in which the positions shown as R ₂ and R ₈ or the positions shown as R ₃ and R ₉ are substituents such as an alkyl group and a phenyl group. In compounds represented by structural formulas such as (27), structural formulas (29) to (35), structural formula (50), and structural formula (51), characteristics such as molecular orientation on the device substrate and crystallinity Therefore, improvement in transistor characteristics can be expected. In addition, for example, in the general formula (1), a compound having a position represented by R ₆ and R ₁₂ as a substituent, in particular, a structural formula (48 wherein the position represented by R ₆ and R ₁₂ is substituted with an alkylsilylenyl group The compound shown as) can be expected to have an effect such as improved solubility.

<Method for Synthesizing Polycyclic Fused Compounds>
Among the above polycyclic fused ring compounds, the polycyclic fused ring compound according to the present invention shown as the structural formula (10) having the most basic constitution is shown by a known method, for example, the following reaction (A). It can be synthesized by synthesizing a distanyl compound, a Stille coupling reaction using a transition metal shown as the reaction (B), an intramolecular cyclization and a demethylation reaction shown as the reaction (C). A detailed example of the synthesis method will be described later.

<Organic semiconductor materials>
As described above, the polycyclic fused ring compound according to the present invention represented by the general formula (1) can be used for an organic semiconductor material. That is, the organic semiconductor material according to the present invention contains a polycyclic fused ring compound represented by the general formula (1). Such an organic semiconductor material according to the present invention can be used as a material for an organic semiconductor device such as an organic transistor. The organic transistor using the organic semiconductor material according to the present invention can be manufactured, for example, by forming a thin film using the organic semiconductor material according to the present invention as a raw material on a substrate.

<Organic transistor>
Next, an organic transistor which is one of organic semiconductor devices using an organic semiconductor material containing a polycyclic fused ring compound according to the present invention represented by the general formula (1) and a manufacturing method thereof will be described.

  First, the organic transistor will be described in detail. The organic transistor includes at least one organic semiconductor layer made of a thin film containing a polycyclic fused ring compound represented by the general formula (1), and a source electrode and a drain disposed so as to be in contact with the organic semiconductor layer and separated from each other An electrode, and a gate electrode disposed so as to face a region (channel region) between a surface in contact with the source electrode and a surface in contact with the drain electrode in the organic semiconductor layer. The current flowing between the source electrode and the drain electrode is controlled by the voltage applied to the gate electrode.

  In general, an organic transistor having a structure (Metal-Insulator-Semiconductor: MIS structure) in which a gate electrode is insulated from an organic semiconductor layer by an insulating layer made of an insulating film is often used as the organic transistor. A MIS structure using a metal oxide film as an insulating film is called a MOS (Metal-Oxide-Semiconductor) structure. Another example of the organic transistor is a structure in which a gate electrode is formed on the organic semiconductor layer through a Schottky barrier (Metal-Semiconductor; MES structure). In some cases, the MIS structure is often used.

  FIG. 1 is a schematic cross-sectional view showing an example of an embodiment of an organic transistor according to the present invention. Organic transistors 10A to 10F shown in FIG. 1 (a) to FIG. 1 (f) are provided with a source electrode 1, an organic semiconductor layer 2, a drain electrode 3, an insulator layer 4, a gate electrode 5 and a substrate 6. Yes. In any of the organic transistors 10A to 10F, the organic semiconductor layer 2 is formed of a thin film using an organic semiconductor material containing a polycyclic fused ring compound represented by the general formula (1). The arrangement of the layers 2 and 4 and the electrodes 1, 3, and 5 can be appropriately selected depending on the use of the organic transistor as exemplified in FIGS. 1A to 1F.

  The organic transistors 10 </ b> A to 10 </ b> D and 10 </ b> F are called lateral transistors because current flows in a direction parallel to the substrate 6, the source electrode 1, and the drain electrode 3. In the organic transistor 10A, the source electrode 1 and the drain electrode 3 are disposed on the lower surface of the organic semiconductor layer 2 (the surface on the side close to the substrate 6), and the gate electrode 5 is interposed below the insulator layer 4 therebetween. Since it is arranged, it is called a bottom contact-bottom gate structure. The organic transistor 10B is called a top contact-bottom gate structure because the source electrode 1 and the drain electrode 3 are disposed on the upper surface of the organic semiconductor layer 2, and the gate electrode 5 is disposed on the lower surface of the insulator layer 4. The organic transistor 10C is called a top contact-top gate structure because the source electrode 1, the drain electrode 3, and the insulator layer 4 are provided on the organic semiconductor layer 2, and the gate electrode 5 is further formed thereon. ing. The organic transistor 10D is called a top & bottom contact-bottom gate structure because the source electrode 1 is disposed on the lower surface of the organic semiconductor layer 2 and the drain electrode 3 is disposed on the upper surface. The organic transistor 10F is called a bottom contact-top gate structure because the gate electrode 5 is disposed on the upper surface of the organic semiconductor layer 2 with the insulator layer 4 interposed therebetween.

  The organic transistor 10E is a kind of organic transistor having a vertical structure in which current flows in a direction perpendicular to the source electrode 1 and the drain electrode 3, and is an electrostatic induction transistor (SIT). The organic transistor 10E includes a source electrode 1 and a drain electrode 3 disposed so as to be parallel and spaced apart from each other, and an organic semiconductor layer 2 disposed so as to be sandwiched between the source electrode 1 and the drain electrode 3. A plurality of gate electrodes 5 embedded in the organic semiconductor layer 2 in a mesh shape parallel to the source electrode 1 and the drain electrode 3. In the organic transistor 10E, since the current flow in the organic semiconductor layer 2 spreads in a planar shape, a large amount of carriers 8 are transferred from the source electrode 1 side to the drain electrode 3 side at a time as indicated by an arrow in FIG. Can move. Although FIG. 1E does not show the substrate 6, in the normal case, a substrate similar to the substrate 6 is provided outside the source electrode 1 and the drain electrode 3 in the organic transistor 10 </ b> E.

  Each component in each embodiment will be described. The substrate 6 needs to be able to hold each component formed thereon without peeling off. Examples of the substrate 6 include an insulating substrate such as a resin plate, a resin film, paper, a glass plate, a quartz plate, and a ceramic plate; a substrate in which an insulating layer is formed by coating or the like on a conductive substrate made of metal or an alloy; A substrate composed of various combinations such as a combination of a resin and an inorganic material; a conductive substrate such as a semiconductor substrate (for example, a silicon wafer) can be used. Examples of the resin constituting the resin plate and the resin film include, for example, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyamide, polyimide, polycarbonate, cellulose triacetate, and polyetherimide. When a resin film or paper is used as the substrate 6, the organic transistors 10A to 10D and 10F can be made flexible, and the organic transistors 10A to 10D and 10F are flexible and lightweight. Practicality is improved. The thickness of the substrate is usually 1 μm to 10 mm, preferably 5 μm to 5 mm.

For the source electrode 1, the drain electrode 3, and the gate electrode 5, a conductive material is used. Examples of the conductive material include platinum, gold, silver, aluminum, chromium, tungsten, tantalum, nickel, cobalt, copper, iron, lead, tin, titanium, indium, palladium, molybdenum, magnesium, calcium, and barium. Metals such as lithium, potassium and sodium and alloys containing them; conductive oxides such as InO ₂ , ZnO ₂ , SnO ₂ and ITO (indium tin oxide); polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene vinylene, Conductive polymer compounds such as polydiacetylene; semiconductors such as silicon, germanium, and gallium arsenide; carbon materials such as carbon black, fullerene, carbon nanotubes, graphite, and graphene can be used. Further, the conductive polymer compound or the semiconductor may be doped. In this case, examples of the dopant used for doping include inorganic acids such as hydrochloric acid and sulfuric acid; organic acids having an acidic functional group such as sulfonic acid; Lewis acids such as PF ₅ , AsF ₅ and FeCl ₃ ; halogen atoms such as iodine. A metal atom such as lithium, sodium or potassium. Boron, phosphorus, arsenic and the like are also frequently used as dopants for inorganic semiconductors such as silicon. Further, a conductive composite material in which particles such as carbon black and metal particles are dispersed in the above dopant is also used. Note that, for the source electrode 1 and the drain electrode 3 that are in contact with the organic semiconductor layer 2, selection of an appropriate work function for reducing contact resistance, surface treatment, and the like are important.

  Further, the distance (channel length) between the source electrode 1 and the drain electrode 3 is an important factor that determines the characteristics of the organic transistors 10A to 10F. The channel length is usually 0.01 to 300 μm, preferably 0.1 to 100 μm. If the channel length is short, the amount of current that can be extracted increases, but conversely, short channel effects such as the influence of contact resistance occur and control becomes difficult, so an appropriate channel length is required. The length (channel width) of the source electrode 1 and the drain electrode 3 is usually 10 to 10000 μm, preferably 100 to 5000 μm. In addition, this channel width can be made longer by forming the electrode structure into a comb structure, etc., and can be set to an appropriate length according to the required amount of current, device structure, etc. There is a need to.

  The structures (shapes) of the source electrode 1 and the drain electrode 3 will be described. The structures of the source electrode 1 and the drain electrode 3 may be the same or different. In the case of the bottom contact structure, it is generally preferable to form the source electrode 1 and the drain electrode 3 using a lithography method, and to form the source electrode 1 and the drain electrode 3 in a rectangular parallelepiped. Recently, printing accuracy by various printing methods has been improved, and it has become possible to produce the source electrode 1 and the drain electrode 3 with high accuracy using techniques such as ink jet printing, gravure printing, and screen printing. In the case of a top contact structure in which the source electrode 1 and the drain electrode 3 are provided on the organic semiconductor layer 2, the source electrode 1 and the drain electrode 3 can be produced by vapor-depositing the conductive material using a shadow mask or the like. . It has also become possible to directly print and form the electrode patterns of the source electrode 1 and the drain electrode 3 using a technique such as inkjet printing. The lengths of the source electrode 1 and the drain electrode 3 are the same as the channel width. The widths of the source electrode 1 and the drain electrode 3 are not particularly limited, but are preferably shorter in order to reduce the area of the device within a range where the electrical characteristics can be stabilized. The width of the source electrode 1 and the drain electrode 3 is usually 0.1 to 1000 μm, preferably 0.5 to 100 μm. The thicknesses of the source electrode 1 and the drain electrode 3 are usually 0.1 to 1000 nm, preferably 1 to 500 nm, and more preferably 5 to 200 nm. Although wiring is connected to the source electrode 1 and the drain electrode 3, the wiring is also made of the same material as the source electrode 1 and the drain electrode 3.

As the insulator layer 4, an insulating material is used. Examples of the insulating material include polyparaxylylene, polyacrylate, polymethyl methacrylate, polystyrene, polyvinylphenol, polyamide, polyimide, polycarbonate, polyester, polyvinyl alcohol, polyvinyl acetate, polyurethane, polysulfone, fluororesin, Polymers such as epoxy resins and phenol resins, and copolymers in which two or more structural units of these polymers are combined; oxides (non-ferroelectric) such as silicon dioxide, aluminum oxide, titanium oxide, tantalum oxide; SrTiO ₃ , BaTiO Ferroelectric oxides such as ₃ ; nitrides such as silicon nitride and aluminum nitride; dielectrics such as sulfides and fluorides can be used. In addition, as the material having the insulating property, a material in which particles of the dielectric (however, a material different from the polymer) are dispersed in a polymer can be used. As the material having the insulating property, a material having high electrical insulation characteristics is preferable in order to reduce the leakage current. Thereby, the thickness of the insulator layer 4 can be reduced, the insulation capacity can be increased, and the current that can be taken out. Can be more. In order to improve the mobility of the semiconductor, it is preferable that the insulator layer 4 is a smooth film that can reduce the surface energy of the surface of the insulator layer 4 and has no unevenness. For this purpose, a self-assembled monolayer insulator layer 4 or a two-layer insulator layer 4 may be formed. The thickness of the insulator layer 4 varies depending on the material, but is usually 0.1 nm to 100 μm, preferably 0.5 nm to 50 μm, more preferably 1 nm to 10 μm.

  The organic semiconductor layer 2 has a thin film using an organic semiconductor material containing the polycyclic fused ring compound according to the present invention represented by the general formula (1). The structure of the organic semiconductor layer 2 is formed as, for example, a single layer structure having only a layer made of a thin film containing the polycyclic fused ring compound according to the present invention. However, for the purpose of improving the characteristics of the organic transistor and imparting various characteristics, it is possible to mix other organic semiconductor materials and various additives as necessary. The organic semiconductor layer 2 can also be formed as a multilayer structure having a layer made of a thin film containing the polycyclic fused ring compound according to the present invention.

  The thickness of the organic semiconductor layer 2 is preferably as thin as possible without losing necessary functions. In the horizontal type organic transistors such as the organic transistors 10A to 10D and 10F, the characteristics of the organic semiconductor device do not depend on the thickness as long as the thickness of the organic semiconductor layer 2 has a predetermined thickness or more. Since the leakage current often increases as the thickness increases, the thickness of the organic semiconductor layer 2 is preferably within an appropriate range. The thickness of the organic semiconductor layer 2 is usually 0.1 nm to 10 μm, preferably 0.5 nm to 3 μm, more preferably, in order for the organic semiconductor layer 2 to perform the function required for the organic semiconductor layer 2. Is 1 nm to 1 μm.

  In the organic transistors 10 </ b> A to 10 </ b> F, other layers may be provided as necessary between the above-described components or on the exposed surfaces of the above-described components. For example, a protective layer may be formed directly or via another layer on the organic semiconductor layer 2 in the organic transistors 10A to 10F. Thereby, the influence of external air such as humidity on the electrical characteristics of the organic transistor can be reduced, and the electrical characteristics of the organic transistor can be stabilized. In addition, electrical characteristics such as the on / off ratio of the organic transistor can be improved.

  Although it does not specifically limit as a material which comprises the said protective layer, For example, various resins, such as acrylic resins, such as an epoxy resin and polymethylmethacrylate, a polyurethane, a polyimide, polyvinyl alcohol, a fluororesin, polyolefin; silicon oxide, aluminum oxide, Inorganic oxides such as silicon nitride; and dielectrics such as nitrides are preferred, and resins (polymers) having low oxygen permeability, moisture permeability, and water absorption are more preferred. As a material constituting the protective layer, a gas barrier protective material developed for an organic EL display can also be used. Although the thickness of a protective layer can employ | adopt arbitrary thickness according to the objective, it is 100 nm-1 mm normally.

  Further, the surface of the organic semiconductor layer 2 (the surface of the substrate 6, the surface of the insulator layer 4, etc.) is subjected to surface treatment before the formation of the organic semiconductor layer 2, whereby the characteristics of the organic transistors 10 </ b> A to 10 </ b> F. It is possible to improve. For example, by adjusting the degree of hydrophilicity / hydrophobicity of the surface on which the organic semiconductor layer 2 is formed, the quality of the organic semiconductor layer 2 formed on the surface (for example, the film quality of the thin film constituting the organic semiconductor layer 2) And film formability) can be improved. In particular, the characteristics of the organic semiconductor layer 2 made of an organic semiconductor material may vary greatly depending on the state of the layer such as molecular orientation. Therefore, the surface treatment on the surface on which the organic semiconductor layer 2 is formed controls the molecular orientation at the interface between the surface on which the organic semiconductor layer 2 is formed and the organic semiconductor layer 2 formed on the surface. It is considered that the trap site in the base material (substrate 6, insulator layer 4, etc.) on which the organic semiconductor layer 2 is formed is reduced, thereby improving characteristics such as carrier mobility of the organic transistor.

  The trap site refers to a functional group such as a hydroxyl group present in an untreated substrate. When such a functional group exists in the base material on which the organic semiconductor layer 2 is formed, electrons are attracted to the functional group, and as a result, the carrier mobility of the organic transistor is lowered. Therefore, reducing trap sites in the base material on which the organic semiconductor layer 2 is formed is often effective for improving characteristics such as carrier mobility of the organic transistor.

  Examples of the surface treatment of the substrate on which the organic semiconductor layer 2 is formed include, for example, self-assembled monolayer treatment with hexamethyldisilazane, octyltrichlorosilane, octadecyltrichlorosilane, etc .; surface treatment with polymers, etc .; hydrochloric acid, Acid treatment with acids such as sulfuric acid and acetic acid; Alkaline treatment with alkali such as sodium hydroxide, potassium hydroxide, calcium hydroxide and ammonia; Ozone treatment; Fluorination treatment; Plasma treatment with plasma such as oxygen plasma and argon plasma; Langmuir・ Blodgett film forming treatment; Other insulator or semiconductor thin film forming treatments; Mechanical treatments; Electrical treatments such as corona discharge; Rubbing treatments using fibers, etc., and combinations of these treatments be able to.

  In the organic transistors 10A to 10F shown in FIG. 1, a method of providing various layers on the base material (a method of providing the insulator layer 4 on the substrate 6, a method of providing the organic semiconductor layer 2 on the substrate 6, the insulator layer 4 As a method for providing the organic semiconductor layer 2 on the surface, various methods such as a vacuum deposition method, a coating method, a printing method, and a sol-gel method can be appropriately employed.

  Next, the manufacturing method of the organic transistor according to the present invention will be described. Here, the top contact-bottom gate type organic transistor 10B of the embodiment shown in FIG. This manufacturing method can be similarly applied to organic transistors of other modes such as the above-described organic transistors 10A, 10C to 10F. FIG. 2 is a schematic view showing a process for producing an embodiment of the organic transistor according to the present invention.

(1) Surface Treatment of Substrate 6 In the method of manufacturing the organic transistor 10B according to the present invention, first, the substrate 6 is prepared (see FIG. 2A), and various layers and electrodes necessary for the substrate 6 are provided. An organic transistor 10B is produced. As the substrate 6, the materials described above are used. It is also possible to perform the above-described surface treatment on the substrate 6. The thickness of the substrate 6 is preferably thin as long as necessary functions are not hindered. Although the thickness of the board | substrate 6 changes also with the material which comprises the board | substrate 6, it is 1 micrometer-10 mm normally, Preferably it is 5 micrometers-5 mm. If necessary, the substrate 6 may have an electrode function.

(2) Formation of Gate Electrode 5 Next, the gate electrode 5 is formed on the substrate 6 (see FIG. 2B). As the material constituting the gate electrode 5, the materials described above are used. As a method for forming the gate electrode 5, various methods can be used. For example, a vacuum deposition method, a sputtering method, a coating method, a thermal transfer method, a printing method, a sol-gel method, or the like can be employed. When forming a layer of a material (electrode material) constituting the gate electrode 5, or after forming the layer, it is preferable to pattern the layer so as to have a desired shape as necessary. Various methods can be used as the layer patterning method, and examples thereof include a photolithography method in which patterning and etching of a photoresist are combined. Also, evaporation method using shadow mask: sputtering method; printing method such as ink jet printing, screen printing, offset printing, letterpress printing, etc .; soft lithography method such as micro contact printing method; or a combination of these methods Thus, the layer can be patterned. The thickness of the gate electrode 5 varies depending on the material constituting the gate electrode 5, but is usually 0.1 nm to 10 μm, preferably 0.5 nm to 5 μm, and more preferably 1 nm to 3 μm. When a single conductive substrate serves as both the gate electrode 5 and the substrate 6, the thickness of the single conductive substrate may be larger than the above-described thickness range of the gate electrode 5.

(3) Formation of insulator layer 4 Next, the insulator layer 4 is formed on the gate electrode 5 (see FIG. 2C). As the material constituting the insulator layer 4, the materials described above are used. Various methods can be used to form the insulator layer 4. Examples of methods that can be used for forming the insulator layer 4 include spin coating, spray coating, dip coating, casting, bar coating, blade coating, and other coating methods; screen printing, offset printing, inkjet printing, and the like; Various methods such as a vacuum deposition method, a molecular beam epitaxial growth method, an ion cluster beam method, an ion plating method, a sputtering method, an atmospheric pressure plasma method, and a dry process method such as a CVD method can be used. In addition to the sol-gel method; a method of forming alumite on aluminum or a method of forming silicon oxide on silicon, the surface layer of metal or metalloid is oxidized by a thermal oxidation method or the like as a method of forming the insulator layer 4. A method of forming an oxide film can also be employed.

  In the portion where the insulator layer 4 and the organic semiconductor layer 2 are in contact with each other, the molecules constituting the organic semiconductor layer 2 at the interface between the insulator layer 4 and the organic semiconductor layer 2, for example, represented by the above general formula (1) In order to satisfactorily orient the molecules of the polycyclic fusedring compound, a predetermined surface treatment can be performed on the insulator layer 4. As a surface treatment method for the insulator layer 4, the same surface treatment as that for the substrate 6 can be used. The thickness of the insulator layer 4 is preferably as thin as possible because the amount of electricity taken out can be increased by increasing the electric capacity of the insulator layer 4. However, since the leakage current increases as the thickness of the insulator layer 4 is thinner, the thickness of the insulator layer 4 is preferably as thin as possible without impairing its function. The thickness of the insulator layer 4 is usually 0.1 nm to 100 μm, preferably 0.5 nm to 50 μm, more preferably 5 nm to 10 μm.

(4) Formation of Organic Semiconductor Layer 2 The organic semiconductor material containing the polycyclic fused ring compound according to the present invention represented by the general formula (1) is used for forming the organic semiconductor layer 2 (FIG. 2 ( d)). In forming the organic semiconductor layer 2, various methods for forming a thin film can be used. Specifically, a forming method by a vacuum process such as a sputtering method, a CVD method, a molecular beam epitaxial growth method, a vacuum deposition method; a coating method such as a dip coating method, a die coater method, a roll coater method, a bar coater method, a spin coating method, And forming methods by solution processes such as an inkjet method, a screen printing method, an offset printing method, and a microcontact printing method.

First, a method of forming an organic semiconductor layer 2 by forming an organic semiconductor material by a vacuum process will be described. As a film forming method by a vacuum process, the organic semiconductor material according to the present invention is accommodated in a crucible or a metal boat, heated in a vacuum, and evaporated, the organic semiconductor material is a substrate 6, an insulator layer 4, a source. It is preferable to employ a method of adhering (vapor deposition) to the electrode 1, the drain electrode 3 or the like, that is, a vacuum vapor deposition method. The degree of vacuum in this case is usually 1.0 × 10 ⁻¹ Pa or less, preferably 1.0 × 10 ⁻³ Pa or less. In addition, since the characteristics of the thin film made of an organic semiconductor material and thus the characteristics of the organic transistor may change depending on the temperature of the substrate 6 during vapor deposition, it is necessary to carefully select the temperature of the substrate 6. The temperature of the substrate 6 during vapor deposition is usually 0 to 250 ° C., preferably 5 to 200 ° C., more preferably 10 to 180 ° C., still more preferably 15 to 150 ° C., and particularly preferably 20 ~ 130 ° C.

  The deposition rate is usually 0.001 nm / second to 10 nm / second, preferably 0.01 nm / second to 1 nm / second. The film thickness of the organic semiconductor layer 2 formed from an organic semiconductor material is usually 1 nm to 1 μm, preferably 5 nm to 500 nm, more preferably 10 nm to 300 nm.

  Note that other methods may be used in place of the vapor deposition method in which the organic semiconductor material for forming the organic semiconductor layer 2 is heated and evaporated to adhere to the substrate 6.

  Next, a method for forming the organic semiconductor layer 2 by forming a film by a solution process will be described. A composition obtained by dissolving the polycyclic fused ring compound represented by the general formula (1) according to the present invention in a solvent or the like, and further adding an additive or the like, if necessary, is the substrate 6, the insulator layer 4, the source It is applied to the electrode 1, the drain electrode 3 and the like. Coating methods include casting, spin coating, dip coating, blade coating, wire bar coating, spray coating, and other coating methods; inkjet printing, screen printing, offset printing, flexographic printing, letterpress printing, and other printing methods; microcontact printing Examples thereof include soft lithography techniques. Furthermore, there is a method in which a plurality of these methods are combined.

  Furthermore, as a method similar to the coating method, the Langmuir-Blodgett method in which the monomolecular film of the organic semiconductor layer 2 produced by dropping the above ink on the water surface is transferred to the substrate 6 and laminated, and the material in the liquid crystal or melt state It is also possible to adopt a method in which the substrate is sandwiched between two substrates 6 and introduced between the substrates 6 by capillary action.

  The environment such as the temperature of the substrate 6 and the organic semiconductor material during film formation is also important. Since the characteristics of the organic transistor to be manufactured may change depending on the temperature of the substrate 6 and the organic semiconductor material, it is necessary to carefully select the temperature of the substrate 6 and the organic semiconductor material. The temperature of the board | substrate 6 is 0-200 degreeC normally, Preferably it is 10-120 degreeC, More preferably, it is 15-100 degreeC. However, care must be taken because it greatly depends on factors such as the solvent used.

  The film thickness of the organic semiconductor layer 2 produced by this method is preferably thinner as long as the function is not impaired. There is a concern that the leakage current increases as the film thickness increases. The film thickness of the organic semiconductor layer 2 is usually 1 nm to 1 μm, preferably 5 nm to 500 nm, more preferably 10 nm to 300 nm.

(5) Post-treatment of organic semiconductor layer 2 The organic semiconductor layer 2 (see FIG. 2D) formed in this way can be further improved in characteristics by post-treatment. For example, by performing heat treatment, distortion in the film generated during film formation is alleviated, pinholes are reduced, and alignment / orientation in the film can be controlled. Improvement and stabilization can be achieved. In the production of the organic transistor according to the present invention, it is effective to improve the characteristics by performing such heat treatment. The heat treatment is performed by heating the substrate 6 after forming the organic semiconductor layer 2. The temperature of the heat treatment is not particularly limited, but is usually from room temperature to about 200 ° C, preferably 40 to 150 ° C, more preferably 45 to 120 ° C. The heat treatment time at this time is not particularly limited, but is usually about 10 seconds to 24 hours, preferably about 30 seconds to 3 hours. The atmosphere at that time may be air, but may be an inert atmosphere such as nitrogen or argon. In addition, the film shape can be controlled by solvent vapor.

  Further, as another post-treatment method of the organic semiconductor layer 2, a characteristic change due to oxidation or reduction can be achieved by treatment with an oxidizing or reducing gas such as oxygen or hydrogen, or an oxidizing or reducing liquid. Can also be induced. Such a post-treatment method is carried out for the purpose of increasing or decreasing the carrier density in the film, for example.

In addition, in a technique called doping, the characteristics of the organic semiconductor layer 2 can be changed by adding a trace amount of dopant (element, atomic group, molecule, or polymer) to the organic semiconductor layer 2. For example, oxidizing gases such as oxygen; reducing gases such as hydrogen; acids such as hydrochloric acid, sulfuric acid and sulfonic acid; Lewis acids such as PF ₅ , AsF ₅ and FeCl ₃ ; halogen atoms such as iodine; sodium and potassium The organic semiconductor layer 2 can be doped with a dopant such as a metal atom; a donor compound such as tetrathiafulvalene (TTF) or phthalocyanine. This is because the organic semiconductor layer 2 is brought into contact with a gaseous dopant (when the dopant is a gas), the organic semiconductor layer 2 is immersed in a solution state dopant (when the dopant is in a solution state), electrochemical This can be achieved by a method of performing a proper doping process. These dopants do not necessarily need to be added after the formation of the organic semiconductor layer 2, and are added during the synthesis of the material (organic semiconductor material) of the organic semiconductor layer 2, or the organic semiconductor layer 2 using a thin film forming composition. May be added to the composition for forming a thin film, or may be added in the process step of forming the organic semiconductor layer 2. Further, a dopant is added to the material forming the organic semiconductor layer 2 (organic semiconductor material) and co-evaporation is performed, or the dopant is mixed in an ambient atmosphere when forming the organic semiconductor layer 2 (the dopant is present). The organic semiconductor layer 2 is formed under an environment), and further, dopant ions can be accelerated in a vacuum and collide with the organic semiconductor layer 2 for doping.

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

(6) Formation of Source Electrode 1 and Drain Electrode 3 Next, the source electrode 1 and the drain electrode 3 are formed on the organic semiconductor layer 2 (see FIG. 2E). The method for forming the source electrode 1 and the drain electrode 3 can be based on the method for forming the gate electrode 5. In forming the source electrode 1 and the drain electrode 3, various additives or the like can be used to reduce the contact resistance with the organic semiconductor layer 2.

(7) Formation of Protective Layer 7 In the step of forming the source electrode 1 and drain electrode 3 described above, the organic transistor 10B (see FIG. 1B and FIG. 2E) is completed. After the formation of the source electrode 1 and the drain electrode 3, a protective layer 7 may be formed on a portion exposed on the upper surface of the organic semiconductor layer 2, the upper surface of the source electrode 1, and the upper surface of the drain electrode 3 (FIG. 2). (Refer to (f)). By forming the protective layer 7 on the exposed portion of the upper surface of the organic semiconductor layer 2, the upper surface of the source electrode 1, and the upper surface of the drain electrode 3, the influence of outside air can be minimized, and the organic transistor There is an advantage that the electrical characteristics of 10B can be stabilized.

  As the material for the protective layer 7, the above-mentioned materials are used. Moreover, the thickness of the protective layer 7 can employ | adopt arbitrary thickness according to the objective, Usually, it is 100 nm-1 mm. As a method of forming the protective layer 7, various methods can be adopted. When the protective layer 7 is made of a resin, for example, a method of applying a solution containing a resin and drying it to obtain a resin layer; Examples thereof include a method of polymerizing after applying or vapor-depositing a resin monomer. You may perform a crosslinking process after formation of a resin layer. When the protective layer 7 is made of an inorganic material, as a method for forming the protective layer 7, for example, a forming method by a vacuum process such as a sputtering method or a vapor deposition method; a forming method by a solution process such as a sol-gel method can be used. .

  In the organic transistor, in addition to the organic semiconductor layer 2, a protective layer 7 can be provided between components as necessary. Such a protective layer 7 may help to stabilize the electrical characteristics of the organic transistor.

  Since the organic transistor according to the present invention uses an organic semiconductor material containing the polycyclic fused ring compound represented by the general formula (1) as a material constituting the organic semiconductor layer 2, the organic transistor is manufactured at a relatively low temperature process. It is possible to manufacture. Therefore, a flexible material such as a plastic plate or a plastic film that could not be used under conditions exposed to a high temperature can be used as the substrate 6 in the organic transistor according to the present invention. As a result, the organic transistor according to the present invention can realize an organic semiconductor device that is lightweight and flexible and is not easily broken by using a flexible material as the substrate 6. Therefore, the organic semiconductor device according to the present invention can be suitably used as a switching device for an active matrix display.

  The organic transistor according to the present invention can also be used as a digital device or an analog device such as a memory circuit device, a signal driver circuit device, and a signal processing circuit device. Further, by combining these, a display, an IC (integrated circuit) card, an IC tag, or the like can be manufactured. Furthermore, since the organic transistor according to the present invention can change its characteristics by an external stimulus such as a chemical substance, it can be used as a sensor.

  Examples in which the polycyclic fused ring compounds represented by the structural formulas (10), (40), (50) and (52) were synthesized are shown in Examples 1 to 4 below. In Examples, “part” means “part by mass” unless otherwise specified, and “%” means “% by mass”. Moreover, the reaction temperature described the internal temperature in a reaction system unless there is particular notice.

  The structural formulas of various compounds obtained in the synthesis examples were determined by analyzing spectra such as ES-MS spectrum (mass spectrometry spectrum) and nuclear magnetic resonance spectroscopy spectrum as necessary. The measuring equipment is as follows.

ES-MS spectrum: QP-5050A manufactured by Shimadzu Corporation
Nuclear magnetic resonance spectroscopy (hereinafter referred to as ¹ H-NMR) spectrum: Lambda 400 type, manufactured by JEOL Ltd.

Example 1 Synthesis of Compound Represented by Structural Formula (10) (1) Synthesis of Compound (a)

In a nitrogen atmosphere at −78 ° C., a solution of naphtho [1,2-b: 5,6-b ′] dithiophene (0.5 g, 2.08 mmol) in anhydrous THF (tetrahydrofuran) (50 mL) slowly Butyl lithium (1.6N hexane solution, 4.0 ml, 6.4 mmol) was mixed. The reaction solution was stirred at −78 ° C. for 30 minutes, then reacted at room temperature for 30 minutes, cooled to −78 ° C., and trimethyltin chloride (1.66 g, 8.34 mmol) was added thereto. After stirring at room temperature for 16 hours, water (50 mL) was added thereto. The obtained mixture was separated, and the aqueous layer was extracted with methylene chloride (50 mL). The organic layer was washed with saturated brine (50 ml × 2), dried over anhydrous magnesium sulfate (MgSO ₄ ), and concentrated under reduced pressure. The obtained residue was recrystallized with acetone to obtain a yellow solid compound (a) (0.88 g, yield 75%).

¹ H-NMR (400 MHz, CDCl ₃ ) 0.49 (s, 18H), 8.06 (d, 2H), 8.11 (s, 2H), 8.30 (d, 2H); EI-MS ( 70 eV) m / z = 566 (M ⁺ )

  (2) Synthesis of compound (b)

  In a toluene (120 ml) solution of degassed compound (a) (1.57 g, 2.8 mmol) and 1-bromo-2- (methylsulfinyl) benzene (1.36 g, 6.2 mmol) under a nitrogen atmosphere. Tetrakis (triphenylphosphine) palladium (0) (0.32 g, 0.28 mmol) was added. The reaction solution was refluxed for 24 hours and then cooled to room temperature. The precipitate was separated by filtration and washed with methanol, dichloromethane and acetone in this order to obtain a white compound (b) (0.56 g, yield 39%).

¹ H-NMR (400 MHz, CDCl ₃ ) 2.56 (s, 6H), 7.57 (s, 2H), 7.61-7.71 (m, 6H), 7.95 (d, 2H), 8.06 (d, 2H), 8.19 (d, 2H); EI-MS (70 eV) m / z = 516 (M ⁺ )

  (3) Synthesis of the compound represented by the structural formula (10)

  Under a nitrogen atmosphere, compound (b) (0.52 g, 1.0 mmol) and trifluoromethanesulfonic acid (15 ml) were mixed and reacted at room temperature for 2 days. Thereafter, water (20 ml) was added, and the obtained solid content was separated by filtration and washed with methanol and acetone. Subsequently, pyridine (50 ml) was added and refluxed for 19 hours. After cooling to room temperature, methanol (50 ml) was added. Then, solid content was separated by filtration and stirred with heating at 180 ° C. for 1 hour in NMP (N-methylpyrrolidone) (50 ml). After cooling to room temperature, the solid content was separated by filtration and washed with water, methanol, and acetone in this order. The dried solid content was purified by vacuum sublimation twice to obtain a white solid compound (0.23 g, yield 51%) represented by the structural formula (10).

EIMS (70 eV) m / z = 452 (M ⁺ )

Example 2 Synthesis of Compound Represented by Structural Formula (40) (1) Synthesis of Compound (c)

  Under a nitrogen atmosphere, 9-borabicyclo [3.3.1] nonane (9-BBN) (0.5N THF solution, 30 ml, 15.0 mmol) and 1-octene (1.68 g, 2.35 mmol) were mixed. And stirred at room temperature for 6 hours. Thereafter, an aqueous sodium hydroxide solution (1.5 N, 10 ml, 15 mmol) and 5,10-dibromo-2,7-bis (triisopropylsilyl) naphtho [1,2-b: 5,6-b ′] dithiophene (3 (.55 g, 5.0 mmol) in THF (100 ml) was added and bubbled with argon for 10 minutes. Subsequently, [1,1'-bis (diphenylphosphino) ferrocene] palladium (II) dichloride dichloromethane adduct (0.408 g, 0.5 mmol) was added, refluxed for 18 hours, and cooled to room temperature. Water (100 ml) was added to the reaction mixture, and the mixture was extracted with chloroform (200 ml) and concentrated under reduced pressure. The obtained residue was purified by flash column chromatography (silica gel, solvent hexane) to obtain a white solid compound (c) (3.30 g, yield 85%).

¹ H-NMR (400 MHz, CDCl ₃ ) 0.88 (t, 3H), 1.19 (d, 36H), 1.25-1.40 (m, 36H), 1.48 (sept, 6H), 1.83 (quant, 4H), 3.09 (t, 4H), 7.68 (s, 2H), 7.78 (s, 2H)

  (2) Synthesis of compound (d)

  Tetrabutylammonium fluoride (1.0 N, 30 ml, 30 mmol) was added to a THF (170 ml) solution of the compound (c) (3.11 g, 4.0 mmol), and the mixture was stirred at room temperature for 6 hours. Water (200 ml) was added to the reaction solution, extracted with chloroform (200 ml), and concentrated under reduced pressure. The resulting residue is purified by flash column chromatography (silica gel, solvent chloroform) and then recrystallized from a mixed solvent of methanol and chloroform to obtain a white solid compound (d) (1.50 g, yield 81%). It was.

¹ H-NMR (400 MHz, CDCl ₃ ) 0.89 (t, 6H), 1.25-1.51 (m, 20H) 1.82 (quint, 4H) 3.09 (quartet, 4H), 7. 51 (d, 2H), 7.56 (d, 2H), 7.77 (s, 2H)
EIMS (70 eV) m / z = 464 (M ⁺ )

  (3) Synthesis of compound (e)

In a nitrogen atmosphere at −78 ° C., slowly add n-BuLi (1.6N hexane solution, 7.5 ml, 12.0 mmol) into a solution of compound (d) (1.4 g, 3.0 mmol) in anhydrous THF (100 mL). ) Was mixed. The reaction solution was reacted at room temperature for 1 hour and then cooled to −78 ° C., and trimethyltin chloride (2.39 g, 12.0 mmol) was added thereto. After stirring at room temperature for 21 hours, water (100 mL) was added thereto. The obtained mixture was separated, and the aqueous layer was extracted with chloroform (100 mL). The organic layer was washed with saturated brine (50 ml × 2), dried over anhydrous magnesium sulfate (MgSO ₄ ), and concentrated under reduced pressure. The obtained residue was recrystallized from acetone to obtain a yellow solid compound (a) (1.82 g, yield 76%).

¹ H-NMR (400 MHz, CDCl ₃ ) 0.46 (t, 18H), 0.87 (t, 6H), 1.25-1.49 (m, 20H, 1.82 (quint, 4H), 3 .08 (t, 4H), 7.59 (t, 2H), 7.75 (s, 2H)

  (4) Synthesis of compound (f)

  In a nitrogen (50 ml) solution of degassed compound (e) (0.79 g, 1.0 mmol) and 1-bromo-2- (methylsulfinyl) benzene (0.53 g, 2.4 mmol). Tetrakis (triphenylphosphine) palladium (0) (0.12 g, 0.1 mmol) was added. The reaction was refluxed for 48 hours and then cooled to room temperature. The reaction mixture was concentrated under reduced pressure, methanol (100 ml) was added, and the resulting solid was filtered off and washed with methanol to give a pale yellow compound (f) (0.47 g, yield 64%). It was.

¹ H-NMR (400 MHz, CDCl ₃ ) 0.87 (t, 6H), 1.24-1.51 (m, 20H), 1.83 (quint, 4H), 2.55 (s, 6H), 3.08 (t, 4H), 7.59-7.72 (m, 8H), 7.76 (s, 2H), 8.20 (d, 2H)

  (5) Synthesis of compound (40)

  Under a nitrogen atmosphere, compound (f) (0.37 g, 0.5 mmol) and trifluoromethanesulfonic acid (10 ml) were mixed and reacted at room temperature for 1 day. Thereafter, water (20 ml) was added, and the resulting solid was filtered off, pyridine (40 ml) was added, refluxed for 20 hours, and cooled to room temperature. Methanol (60 ml) was added to the reaction solution, the solid content was filtered off, and washed with methanol, methylene chloride and acetone in this order. The dried solid was purified by sublimation in vacuo, recrystallized with NMP (50 ml), and washed with methanol and acetone. The dried solid was purified by vacuum sublimation to obtain a yellow solid compound (0.17 g, yield 49%) represented by the structural formula (40).

¹ H-NMR (400 MHz, CDCl ₃ ) 0.90 (t, 6H), 1.25-1.70 (m, 20H), 1.92 (quint, 4H), 3.29 (t, 4H), 7.48 (m, 4H), 7.87 (s, 2H), 7.97 (t, 4H)
EIMS (70 eV) m / z = 680 (M ⁺ )

Example 3 Synthesis of Compound Represented by Structural Formula (50) (1) Synthesis of Compound (g)

  In a nitrogen atmosphere, a degassed compound (a) (0.75 g, 1.3 mmol) and 3-methylthiosulfinyl-4-trifluoromethanesulfonylbiphenyl (1.16 g, 3.2 mmol) in a toluene (100 ml) solution. Tetrakis (triphenylphosphine) palladium (0) (0.15 g, 0.13 mmol) was added. The reaction solution was refluxed for 63 hours and then cooled to room temperature. The precipitate was separated by filtration and washed with methanol, dichloromethane and acetone in this order to obtain a yellow compound (g) (0.45 g, yield 56%).

¹ H-NMR (400 MHz, CDCl ₃ ) 2.60 (s, 6H), 7.41-7.55 (m, 6H), 7.70-7.79 (m, 6H), 7.84 (dd , 2H), 8.07 (d, 2H), 8.19 (s, 2H), 8.33 (d, 2H), 8.45 (d, 2H); EI-MS (70 eV) m / z = 668 (M ⁺ )

  (2) Synthesis of the compound represented by the structural formula (50)

  Under a nitrogen atmosphere, compound (g) (0.30 g, 0.45 mmol) and trifluoromethanesulfonic acid (10 ml) were mixed and reacted at room temperature for 2 days. Thereafter, water (20 ml) was added, and the obtained solid content was separated by filtration and washed with methanol and acetone. Subsequently, pyridine (30 ml) was added, refluxed for 20 hours, cooled to room temperature, and then methanol (50 ml) was added. Then, solid content was separated by filtration and stirred with heating at 180 ° C. for 1 hour in NMP (N-methylpyrrolidone) (30 ml). After cooling to room temperature, the solid content was separated by filtration and washed with water, methanol, and acetone in this order. The dried solid was subjected to vacuum sublimation purification twice to obtain a yellow solid compound (0.085 g, yield 31%) represented by the structural formula (50).

  FIG. 3 is a graph showing an ultraviolet-visible absorption spectrum of a thin film of a polycyclic fused ring compound according to the present invention. Using a thin film of a polycyclic fused ring compound represented by the structural formula (50) as a material for optical absorption spectrum measurement, light is measured with an ultraviolet-visible-near infrared spectrophotometer (manufacturer: Shimadzu Corporation, model number: UV-3600) Absorption spectrum was measured. The measured light absorption spectrum is shown in FIG. 3 as a graph showing the wavelength (nm) on the horizontal axis and the absorbance on the vertical axis.

EIMS (70 eV) m / z = 604 (M ⁺ ); λmax: 405 nm (thin film)

Example 4 Synthesis of Compound Represented by Structural Formula (52) (1) Synthesis of Compound (h)

  Under a nitrogen atmosphere, 5,10-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-ene) -2,7-bis (triisopropylsilyl) naphtho [1,2 -B: 5,6-b '] dithiophene (2.20 g, 2.73 mmol) and iodobenzene (1.39 g, 6.83) in THF (50 ml) solution in aqueous potassium carbonate (2N, 10 ml, 20 mmol) ) And bubbled with argon for 10 minutes. Tetrakis (triphenylphosphine) palladium (0) (0.32 g, 0.27 mmol) was added to the reaction solution, refluxed for 24 hours, and then cooled to room temperature. Then, water (100 ml) was added, extracted with chloroform (300 ml), concentrated under reduced pressure, methanol (100 ml) was added and the solid content was separated by filtration. The solid content was washed with methanol to obtain a white solid compound (h) (1.87 g, yield 97%).

¹ H-NMR (400 MHz, CDCl ₃ ) 1.14 (d, 36H), 1.41 (quint, 6H), 7.44-7.57 (m, 6H), 7.72 (t, 6H), 8.03 (s, 2H)

  (2) Synthesis of compound (i)

  Tetrabutylammonium fluoride (1.0 N, 45 ml, 45 mmol) was added to a THF (300 ml) solution of the compound (h) (1.73 g, 2.46 mmol), and the mixture was stirred at room temperature for 21 hours. Water (200 ml) was added to the reaction solution, extracted with chloroform (300 ml), dried over magnesium sulfate and concentrated under reduced pressure. The resulting residue was purified by flash column chromatography (silica gel, solvent chloroform) to obtain a yellow solid compound (i) (0.92 g, yield 95%).

¹ H-NMR (400 MHz, CDCl ₃ ) 7.48-7.52 (m, 10H), 7.74 (dd, 4H), 8.04 (s, 2H)
EIMS (70 eV) m / z = 392 (M ⁺ )

  (3) Synthesis of compound (j)

  In a nitrogen atmosphere at −78 ° C., slowly add n-BuLi (1.6N hexane solution, 4.5 ml, 7.2 mmol) into a solution of compound (i) (0.90 g, 2.3 mmol) in anhydrous THF (120 mL). ) Was mixed. The reaction solution was reacted at 50 ° C. for 1 hour, cooled to −78 ° C., and trimethyltin chloride (1.51 g, 7.6 mmol) was added thereto. After stirring at room temperature for 16 hours, water (100 mL) was added thereto. The obtained mixture was separated, and the aqueous layer was extracted with methylene chloride (100 mL × 2). The organic layer was washed with saturated brine (50 ml × 2), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The obtained residue was washed with methanol to obtain a yellow solid compound (j) (1.43 g, yield 87%).

¹ H-NMR (400 MHz, CDCl ₃ ) 0.43 (t, 18H), 7.47-7.60 (m, 6H), 7.63 (s, 2H), 7.74 (d, 4H), 8.02 (s, 2H)

  (4) Synthesis of compound (k)

  In a nitrogen atmosphere, a degassed compound (j) (1.42 g, 2.0 mmol) and 1-bromo-2- (methylsulfinyl) benzene (0.92 g, 4.2 mmol) in a toluene (90 ml) solution. Tetrakis (triphenylphosphine) palladium (0) (0.23 g, 0.20 mmol) was added. The reaction was refluxed for 48 hours and then cooled to room temperature. The reaction mixture was concentrated under reduced pressure, methanol (100 ml) was added, and the resulting solid was filtered off. Thereafter, the product was dissolved in methylene chloride (200 ml), passed through celite, and concentrated under reduced pressure to obtain a yellow compound (k) (1.09 g, yield 83%).

¹ H-NMR (400 MHz, CDCl ₃ ) 2.58 (s, 6H), 7.49-7.73 (m, 18H), 8.04 (s, 2H), 8.17 (d, 2H)

  (5) Synthesis of the compound represented by the structural formula (52)

  Under a nitrogen atmosphere, compound (k) (0.60 g, 0.90 mmol) and trifluoromethanesulfonic acid (15 ml) were mixed and reacted at room temperature for 22 hours. Thereafter, water (20 ml) was added, and the resulting solid was filtered off and washed with water and methanol. Then, pyridine (25 ml) was added, refluxed for 19 hours, and cooled to room temperature. Methanol (30 ml) was added to the reaction solution, the solid content was filtered off, NMP (10 ml) was added and the mixture was heated and washed at 180 ° C. The solid content was filtered off and washed with NMP and acetone. The dried solid content was purified by vacuum sublimation twice to obtain a yellow solid compound (0.24 g, yield 44%) represented by the structural formula (52).

EIMS (70 eV) m / z = 604 (M ⁺ )

  Next, the compound represented by structural formula (10), the compound represented by structural formula (40), and the compound represented by structural formula (50) obtained in Example 1, Example 2 and Example 3. Examples in which an organic transistor is formed by using are shown as the following Example 5, Example 6, and Example 7.

<Example 5> Preparation of organic transistor using compound represented by structural formula (10) 200-nm SiO ₂ thermally oxidized film-coated n-doped silicon wafer subjected to octadecyltrichlorosilane treatment (surface resistance 0.02 Ω · cm or less) ) Was placed in a vacuum vapor deposition apparatus and evacuated until the degree of vacuum in the apparatus was 1.0 × 10 ⁻³ Pa or less. Under the condition that the temperature of the substrate 6 is set to about 200 ° C. on this electrode by resistance heating vapor deposition, the compound represented by the structural formula (10) prepared in Example 1 is 50 nm at a deposition rate of 1 kg / sec. The organic semiconductor layer 2 was formed by vapor deposition. Next, a shadow mask for electrode preparation is attached to this substrate 6 and placed in a vacuum vapor deposition apparatus. The vacuum inside the apparatus is evacuated to 1.0 × 10 ⁻⁴ Pa or less, and is made of gold by resistance heating vapor deposition. The electrodes, ie, the source electrode 1 and the drain electrode 3 were deposited to a thickness of 80 nm to obtain a top contact type organic transistor according to the present invention (channel length 40 μm, channel width 3 mm).

  In this example, an organic transistor shown as the top contact-bottom gate type organic transistor 10B in FIG. 1B was manufactured. Further, in the organic transistor in this example, the thermal oxide film in the n-doped silicon wafer with the thermal oxide film has the function of the insulator layer 4, and the n-doped silicon wafer has the functions of the substrate 6 and the gate electrode 5. Yes. The obtained organic transistor was installed in a prober, and semiconductor characteristics were measured using a semiconductor parameter analyzer 4200SCS (manufactured by TFF Keithley Instruments Co., Ltd.).

  FIG. 4 is a graph showing semiconductor characteristics of the organic transistor according to the present invention. FIG. 4A shows the current-voltage characteristics of the organic transistor prepared as Example 5 with the drain voltage (Vd / V) on the horizontal axis and the drain current (−Id / A) on the vertical axis. It is a graph. The gate voltage (Vg) is set at intervals of 10V from -60V to 0V, and current-voltage characteristics are measured at each setting. From the current-voltage characteristics shown in FIG. 4A, the organic transistor according to Example 5 is saturated regardless of the gate voltage when the drain voltage is −60V.

In FIG. 4B, the horizontal axis represents the gate voltage (Vg / V), the vertical axis represents the drain current (−Id / A; left end scale), and the square root of the absolute value of the drain current (| Id | ^1/2). / A ^1/2 ; right end scale) and is a graph showing the characteristics of the organic transistor produced as Example 5. FIG. 4B shows the result of measuring the drain current-gate voltage (transfer) characteristics by fixing the drain voltage to −60 V which is the saturation region, scanning the gate voltage from 20 V to −60 V.

  From the measurement results, the threshold voltage, carrier mobility, and on / off ratio were obtained as numerical values indicating the semiconductor characteristics of the organic transistor prepared as Example 5. The method for obtaining each numerical value indicating the semiconductor characteristics is as follows.

<Threshold voltage>
In the graph showing the relationship between the gate voltage (Vg / V) and the square root of the absolute value of the drain current (| Id | ^1/2 / A1 / ² ) shown in FIG. 4B, the slope is near 0V. It has changed greatly. In the graph shown in FIG. 4B, the threshold voltage linearly approximates a range in which the slope can be regarded as substantially constant (−60 to −30 V in the measurement result illustrated in FIG. 4B), and the approximate line is A voltage value at a point where the extrapolated straight line intersects the X axis (a point where Id = 0 A) was obtained.

<Carrier mobility>
Since the current-voltage characteristic in the saturation region is expressed by the following formula a, the carrier mobility was calculated using the formula a.

Id = (1/2) W [mu] Cp (Vg-Vth) < ² > / L Equation a
Where Id: drain current
W: Channel width
μ: Carrier mobility
Cp: Capacitance of the insulator layer 4
Vg: Gate voltage
Vth: threshold voltage
L: Channel length

<On / off ratio>
The on / off ratio was calculated as a ratio between the maximum value of the drain current (current value when Vd = −60 V) and the minimum value within the measurement range of the current-voltage characteristics.

In this measurement, the channel width W is 3000 μm, the capacitance of the insulating layer 4 is 17.3 × 10 ⁻⁹ F, and the channel length L is 40 μm. Further, the gate voltage Vg was set to −60 V which becomes a saturation region.

Based on the above measurement and calculation, the carrier mobility of the organic transistor according to Example 4 is 4.4 × 10 ⁻¹ cm ² / Vs, the threshold voltage is −22 V, and the on / off ratio I _on / I _off is 10 It was ⁶ .

  Further, the ionization potential of the organic semiconductor material used for the organic transistor prepared as Example 5, that is, the polycyclic fused ring compound represented by Structural Formula (10) prepared as Example 1 was measured. The ionization potential is used as one of the indicators of atmospheric stability of organic semiconductor materials. In general, the ionization potential is preferably a value larger than 5.0 eV, and when it is larger than 5.0 eV, it is evaluated as having atmospheric stability. In addition, the measurement of ionization potential shall measure the thin film of the organic-semiconductor material which concerns on Example 1 on ITO glass by the vacuum evaporation method, and measures using AC-2 by Riken Keiki Co., Ltd.

  The measured value of the ionization potential of the polycyclic fused ring compound represented by the structural formula (10) prepared as Example 1 was 5.6 eV. As a reference experiment, a similar experiment was performed using pentacene, which is one of the polycyclic fused ring compounds conventionally known as materials for organic transistors. As a result, the measured ionization potential of pentacene was 5.0 eV. That is, the polycyclic fused-ring compound according to the present invention represented by the structural formula (10) has sufficiently high atmospheric stability, and its value is superior to pentacene, which is a known organic semiconductor material. It has been found.

  Further, the organic transistor prepared as Example 5 was stored for 6 months in an air atmosphere, and the change with time of each characteristic value was measured. Hereinafter, the measured values of carrier mobility, threshold voltage, and on / off ratio of the organic transistor are shown immediately after creation and after 6 months.

  The characteristics were as described above, and although there was a slight decrease in mobility and on / off ratio, it was possible to drive without problems and to confirm that it had sufficient atmospheric stability. .

Example 6 Production of Organic Transistor Using Compound Represented by Structural Formula (40) Compound represented by Structural Formula (10) Obtained in Example 1 as a Polycyclic Fused Compound According to the Present Invention Instead of this, an organic transistor was produced using the compound represented by the structural formula (40) obtained in Example 2. The conditions other than the used polycyclic fused ring compound are the same as in Example 5. The semiconductor characteristics of the obtained organic transistor were measured by the same method as in Example 5.

  FIG. 5 is a graph showing semiconductor characteristics of the organic transistor according to the present invention. FIG. 5A shows the current-voltage characteristics of the organic transistor produced as Example 5 with the drain voltage (Vd / V) on the horizontal axis and the drain current (−Id / A) on the vertical axis. It is a graph. From the current-voltage characteristics shown in FIG. 5A, the organic transistor according to Example 6 is saturated regardless of the gate voltage when the drain voltage is −60V.

In FIG. 5B, the horizontal axis represents the gate voltage (Vg / V), the vertical axis represents the drain current (−Id / A; left end scale), and the square root of the absolute value of the drain current (| Id | ^1/2). / A ^1/2 |; right scale) is a graph showing the characteristics of the organic transistor produced as Example 6. FIG. 5B shows the result of measuring the drain current-gate voltage (transfer) characteristics by fixing the drain voltage to −60 V which is the saturation region, scanning the gate voltage from 20 V to −60 V.

  From the measurement results, the carrier mobility, threshold voltage, and on / off ratio of the organic transistor prepared as Example 6 were determined. The specific conditions are the same as in Example 5.

Based on the above measurement and calculation, the carrier mobility of the organic transistor according to Example 6 is 4.2 × 10 ⁻¹ cm ² / Vs, the threshold voltage is −8 V, and the on / off ratio I _on / I _off is 10 It was ⁶ .

  In addition, for the organic semiconductor material used in the organic transistor prepared as Example 6, that is, the polycyclic fused ring compound represented by the structural formula (40) prepared as Example 2, by the same method as in Example 5, The ionization potential was measured.

  The measured value of the ionization potential of the polycyclic fused ring compound represented by the structural formula (40) prepared as Example 2 was 5.5 eV. That is, the polycyclic fused ring compound according to the present invention represented by the structural formula (40) also has sufficiently high atmospheric stability, and its value is superior to that of pentacene, which is a known organic semiconductor material. It turned out that.

  Further, the organic transistor prepared as Example 6 was stored for 6 months in the atmosphere, and the change with time of each characteristic value was measured. Hereinafter, the measured values of carrier mobility, threshold voltage, and on / off ratio of the organic transistor are shown immediately after creation and after 6 months.

  The characteristics were as described above, and although there was a slight decrease in mobility and on / off ratio, it was possible to drive without problems and to confirm that it had sufficient atmospheric stability. .

<Example 7> Preparation of organic transistor using compound represented by structural formula (50) Compound represented by structural formula (10) obtained in Example 1 as a polycyclic fused ring compound according to the present invention Instead of this, an organic transistor was produced using the compound represented by the structural formula (50) obtained in Example 3. The conditions other than the used polycyclic fused ring compound are the same as in Example 5. The semiconductor characteristics of the obtained organic transistor were measured by the same method as in Example 5.

  FIG. 6 is a graph showing the semiconductor characteristics of the organic transistor according to the present invention. FIG. 6A shows the current-voltage characteristics of the organic transistor prepared as Example 5 with the drain voltage (Vd / V) on the horizontal axis and the drain current (−Id / A) on the vertical axis. It is a graph. From the current-voltage characteristics shown in FIG. 6A, the organic transistor according to Example 7 is saturated regardless of the gate voltage when the drain voltage is −60V.

In FIG. 6B, the horizontal axis represents the gate voltage (Vg / V), the vertical axis represents the drain current (−Id / A; left-end scale), and the square root of the absolute value of the drain current (| Id | ^1/2). / A ^1/2 |; right end scale) is a graph showing the characteristics of the organic transistor produced as Example 7. FIG. 6B shows the result of measuring the drain current-gate voltage (transfer) characteristics by fixing the drain voltage to −60 V which is the saturation region, scanning the gate voltage from 20 V to −60 V.

  From the measurement results, the carrier mobility, threshold voltage, and on / off ratio of the organic transistor prepared as Example 7 were determined. The specific conditions are the same as in Example 5.

Based on the above measurement and calculation, the carrier mobility of the organic transistor according to Example 7 is 6.0 × 10 ⁻¹ cm ² / Vs, the threshold voltage is −15 V, and the on / off ratio I _on / I _off is 10 It was ⁶ .

  In addition, for the organic semiconductor material used in the organic transistor prepared as Example 7, that is, the polycyclic fused ring compound represented by the structural formula (50) prepared as Example 3, by the same method as in Example 5, The ionization potential was measured.

  The measured ionization potential of the polycyclic fused ring compound represented by the structural formula (50) prepared as Example 3 was 5.7 eV. That is, the polycyclic fused ring compound according to the present invention represented by the structural formula (50) also has sufficiently high atmospheric stability, and its value is superior to that of pentacene, which is a known organic semiconductor material. It turned out that.

  Further, the organic transistor prepared as Example 7 was stored in the atmosphere for one month, and the change with time of each characteristic value was measured. Hereinafter, the measured values of the carrier mobility, the threshold voltage, and the on / off ratio of the organic transistor are shown immediately after creation and after one month.

  The characteristics were as described above, and although there were some changes in mobility and threshold voltage, it was possible to drive without problems and to confirm that it had sufficient atmospheric stability.

  As explained in detail above, the polycyclic fused ring compound (organic semiconductor material) according to the present invention can be used as a material for a thin film forming an organic semiconductor layer of an organic transistor. Since the polycyclic fused ring compound of the present invention has high carrier mobility as a material of the organic semiconductor layer, this organic transistor has a high response speed (driving speed) and high performance as a transistor. It can also be used as an organic thin film light emitting transistor capable of emitting light.

  Although several embodiments and / or examples of the present invention have been described in detail above, those skilled in the art will appreciate that these exemplary embodiments and / or embodiments are substantially without departing from the novel teachings and advantages of the present invention. It is easy to make many changes to the embodiment. Accordingly, many of these modifications are within the scope of the present invention.

  The polycyclic fused ring compound according to the present invention can be suitably used as a material for an organic semiconductor device such as an organic transistor as an organic semiconductor material. The organic semiconductor device according to the present invention can be used in fields such as a diode, a capacitor, a thin film photoelectric conversion device, a dye-sensitized solar cell, and an organic EL device in addition to an organic transistor.

1 Source electrode 2 Organic semiconductor layer 3 Drain electrode 4 Insulator layer 5 Gate electrode 6 Substrate 7 Protective layer

Claims (12)

General formula (1)

(In General Formula (1), X < ₁ > -X < ₄ > represents an oxygen atom, a sulfur atom, or a selenium atom each independently, and R < ₁ > -R < ₁₂ > is respectively independently a hydrogen atom, a halogen atom, substitution, or An unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted haloalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted carbon group having 1 to 30 carbon atoms Haloalkoxy group, substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, substituted or unsubstituted haloalkylthio group having 1 to 30 carbon atoms, substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, substituted Or an unsubstituted dialkylamino group having 2 to 60 carbon atoms (the alkyl groups may be bonded to each other to form a cyclic structure containing a nitrogen atom), substituted or unsubstituted carbon number -30 alkylsulfonyl group, substituted or unsubstituted haloalkylsulfonyl group having 1 to 30 carbon atoms, substituted or unsubstituted aryl group having 3 to 60 carbon atoms, substituted or unsubstituted alkylsilyl group having 3 to 20 carbon atoms A substituted or unsubstituted alkylsilylethynyl group having 5 to 60 carbon atoms, a substituted or unsubstituted arylamino group having 3 to 60 carbon atoms, a substituted or unsubstituted diarylamino group having 6 to 120 carbon atoms, or a cyano group. A polycyclic fusedring compound represented by the formula: The polycyclic fused ring compound according to claim 1,
X < ₁ > -X < ₄ > is a sulfur atom, The polycyclic fused-ring compound characterized by the above-mentioned. The polycyclic fusedring compound according to claim 1 or 2, wherein
R ₆ and R ₁₂ are each an alkyl group having 1 to 30 carbon atoms. The polycyclic fusedring compound according to claim 1 or 2, wherein
A polycyclic fused ring compound, wherein R ₆ and R ₁₂ are substituted or unsubstituted phenyl groups. The polycyclic fusedring compound according to claim 1 or 2, wherein
A polycyclic fused ring compound, wherein R ₆ and R ₁₂ are alkylsilylethynyl groups having 5 to 60 carbon atoms. It is a polycyclic fused-ring compound of any one of Claims 1 thru | or 5, Comprising:
A polycyclic condensed ring compound, wherein R _{1 to} R ₅ and R _{7 to} R ₁₁ are hydrogen atoms. The polycyclic fusedring compound according to claim 1 or 2, wherein
A polycyclic fused ring compound, wherein R ₂ and R ₈ are substituted or unsubstituted phenyl groups. The polycyclic condensed ring compound according to claim 7,
A polycyclic fused ring compound, wherein R ₁ , R _{3 to} R ₇ and R _{9 to} R ₁₂ are hydrogen atoms.   An organic semiconductor material comprising the polycyclic fusedring compound according to any one of claims 1 to 8. The organic semiconductor material according to claim 9,
An organic semiconductor material characterized by being a material for an organic transistor.   An organic semiconductor device comprising a thin film formed using the organic semiconductor material according to claim 9. A substrate,
A gate electrode disposed on the substrate;
A source electrode and a drain electrode spaced apart on the substrate;
An insulator layer that electrically insulates between the gate electrode and the source and drain electrodes;
An organic semiconductor layer in contact with the source electrode and the drain electrode,
The said organic-semiconductor layer is formed using the organic-semiconductor material of Claim 10. The organic transistor characterized by the above-mentioned.

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