JP2014175466A - Organic semiconductor material and organic semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic semiconductor material and an organic semiconductor device, in which steric hindrance can be reduced.SOLUTION: An organic semiconductor material includes polymer compound having a skeleton represented as a formula 1A or a formula 1B. In the formula 1A and the formula 1B, Z independently represents oxygen, sulfur or selenium, and R independently represents hydrogen or an alkyl group.

Description

  The present invention relates to an organic semiconductor material and an organic semiconductor device.

  In recent years, field effect transistors and the like using organic semiconductors as active layers have been actively developed. In order to improve the carrier mobility of the organic semiconductor polymer, it is important to strengthen the intermolecular force between the polymer chains and form a strong π-stacking structure.

  Since the dye-based molecule has a strong intermolecular force, the formation of a strong π-stacking structure and high carrier mobility are expected by introducing the dye-based molecular skeleton into the main chain skeleton of the polymer. A compound having a skeleton of quinacridones in which five 6-membered rings are condensed is known (Patent Document 1). Moreover, although it is not a pigment | dye, the compound in which five 6-membered rings are condensed and has amide bridge | crosslinking is known (patent document 2, nonpatent literature 1). As a characteristic of such a molecular skeleton, polarization occurs within the molecule by having an amino group and a ketone group, or by having an amide group that is a complex of these, and molecules are generated by dipole-dipole interaction between molecules. It is conceivable that the interstitial force increases and a strong π-stacking structure is formed.

JP 2012-184310 A US Patent Application Publication No. 2007/0050927

Jaydeep J. S. Lamba and James M. Tour; Imine-Bridged Planar Poly (p-phenylene) Derivatives for Maximization of Extended π-Conjugation.The Common Intermediate Approach; J. Am. Chem. Soc. 1994, 116, 11723-11736

  Patent Documents 1 and 2 and Non-Patent Document 1 all have a skeleton in which five 6-membered rings are condensed. In the case of a 6-membered ring, it is difficult to improve the coplanarity of the main chain due to steric hindrance by incorporating it into the polymer main chain. For this reason, there is a problem that it is difficult to form a highly oriented molecular arrangement.

  This invention is made | formed in view of the said matter, and it aims at providing the organic-semiconductor material and organic-semiconductor device which can relieve a steric hindrance.

The organic semiconductor material according to the first aspect of the present invention is:
Containing a polymer compound having a skeleton represented by Formula 1A or Formula 1B;
It is characterized by that.
(In Formula 1A and Formula 1B, Z independently represents oxygen, sulfur or selenium, and R independently represents hydrogen or an alkyl group.)

The organic semiconductor material according to the second aspect of the present invention is
Containing a polymer compound represented by Formula 2A or Formula 2B,
It is characterized by that.
(In Formula 2A and Formula 2B, Z represents oxygen, sulfur, or selenium each independently, R represents hydrogen or an alkyl group each independently, Y represents the structure represented by Formula 3, and m is 0 or more. Represents an integer, and n represents a positive real number.)
(Wherein, W represents carbon or nitrogen. In the case of carbon, W has any of hydrogen, halogen, alkyl group, alkoxy group, alkoxycarbonyl group or alkylcarbonyl group as a substituent, and Ar is a divalent group. Represents a heterocyclic group, and l and r each independently represents an integer of 0 or more.)

The organic semiconductor device according to the third aspect of the present invention is
Containing the organic semiconductor material according to the first or second aspect of the present invention,
It is characterized by that.

  The organic semiconductor material according to the present invention contains a polymer compound having a skeleton in which three 6-membered rings are condensed and condensed at both ends thereof. Since the steric hindrance is relaxed in the 5-membered ring as compared with the 6-membered ring, the planarity in the molecule is increased. For this reason, a highly oriented molecular arrangement is formed, electron transfer due to hopping between polymer main chains is likely to occur, and good charge mobility can be exhibited.

It is a graph which shows the transfer characteristic of the transistor element produced using the high molecular compound P1. It is a graph which shows the output characteristic of the transistor element produced using the high molecular compound P1.

The organic semiconductor material according to the present embodiment contains a polymer compound having a skeleton represented by Formula 1A or Formula 1B.

  In formula 1A and formula 1B, Z represents oxygen, sulfur or selenium, and Z may be the same or different, but is preferably the same.

  Moreover, R represents hydrogen and an alkyl group in Formula 1A and Formula 1B. R may be the same or different. In the case of an alkyl group, the number of carbon atoms is preferably 6-30, and more preferably 8-24. The alkyl group may be either a linear alkyl group or a branched alkyl group, but is preferably a branched alkyl group. In the case of a branched alkyl group, the solubility of the organic semiconductor material in an organic solvent is improved, so that the organic semiconductor layer can be more preferably produced using a solution method.

Moreover, it is preferable that the organic semiconductor material which concerns on this Embodiment contains the high molecular compound represented by Formula 2A or Formula 2B.

  In Formula 2A and Formula 2B, Z and R have the same meanings as Formula 1A and Formula 1B described above. M represents an integer of 0 or more, and n represents a positive real number.

In Formulas 2A and 2B, Y is a structure represented by Formula 3.

  In Formula 3, W represents carbon or nitrogen each independently, and may be the same or different. When W is carbon, it has any of hydrogen, halogen, alkyl group, alkoxy group, alkoxycarbonyl group or alkylcarbonyl group as a substituent. L and r each independently represents an integer of 0 or more.

In Formula 3, Ar represents a divalent heterocyclic group, and examples of Ar include structures represented by Formulas 4 to 27. In formula 4 to formula 27, R represents hydrogen or an alkyl group. When it is an alkyl group, it may be linear or branched, and preferably has 6 to 30 carbon atoms, more preferably 8 to 24 carbon atoms.

  The above polymer compound has a skeleton in which three 6-membered rings are condensed and 5-membered rings are condensed at both ends. Since this skeleton has an amide bridge structure, it has a strong intermolecular force due to dipole-dipole interaction due to intramolecular polarization. Since the intermolecular force between the polymer chains is strong, formation of a π-stacking structure and high carrier mobility can be expected.

  In addition, a 5-membered ring is provided at both ends of the skeleton, and the steric hindrance is relaxed in the 5-membered ring as compared with the 6-membered ring, so that the coplanarity in the polymer main chain is increased. For this reason, it is expected that a highly oriented molecular arrangement is formed, electron transfer is easily caused by hopping between polymer main chains, and good charge mobility is exhibited.

  Further, the organic semiconductor material may contain other substances as long as the properties of the polymer compound having a skeleton represented by Formula 1A, Formula 1B, Formula 2A, or Formula 2B are not impaired. Alternatively, the electric field mobility may be adjusted by doping impurities using a known method.

The above-described polymer compound can be synthesized, for example, as follows. First, as shown in the following reaction formula, a compound represented by formula 28 such as 1,4-dihalogenobenzene and a boronic ester are reacted to form boron, and a compound represented by formula 29 is synthesized.

Further, as shown in the following reaction formula, the compound represented by the formula 30 is reacted with the halide to synthesize the compound represented by the formula 31. Furthermore, the compound represented by Formula 31 is reacted with a primary amine to synthesize the compound represented by Formula 32 having an amide bond.

Subsequently, as shown in the following reaction formula, the compound represented by formula 29 and the compound represented by formula 32 are reacted to bond the chalcogenophene ring to the benzene ring, thereby synthesizing the compound represented by formula 33. To do. Furthermore, the compound represented by Formula 34 can be synthesized by cyclizing the compound represented by Formula 33 using a cyclizing agent. Furthermore, the compound represented by Formula 34 is polymerized by reacting with the compound represented by Formula 35 having a substituent having an organic metal such as a trialkyltin group or a borate group, and represented by Formula 2A. A polymer compound can be synthesized.

In Formulas 28 to 35, X ^{1 to} X ³ represent halogen, and X ³ has a larger atomic number than X ¹ and X ² . X ⁴ represents a reactive substituent having an organic metal such as trialkyltin or borate ester. B represents a boronic acid, and R represents hydrogen or an alkyl group. Z is synonymous with Formula 1A and Formula 1B described above, and Ar, W, and n are synonymous with Formula 3 described above. In addition, each of the above reactions may be appropriately performed using an appropriate solvent, catalyst, reaction accelerator, and the like.

In Formula 34, X ² is substituted with a reactive group having an organic metal such as trialkyltin or borate ester by a known method, and polymerized with a compound represented by Formula 35 having a halogen group as X ^4. In this way, the polymer compound represented by the formula 2A can be synthesized.

  An organic semiconductor device is a device manufactured using the organic semiconductor material described above. Examples of the organic semiconductor device include various devices such as a field effect transistor element, a light emitting device, and a photoelectric conversion element having an organic semiconductor layer.

  The method for producing the organic semiconductor layer in the organic semiconductor device is not particularly limited, and various conventionally known production methods can be used. Among them, a solution method can be suitably used as a method for producing the organic semiconductor layer by disposing the organic semiconductor material on a support. The solution method is a method for preparing a semiconductor device by dissolving the organic semiconductor material in various organic solvents and forming an organic thin film on a support by a coating method, a spin coating method, an ink jet method or the like. Since the organic semiconductor material is soluble in an organic solvent as described above, the welding method is suitably applied.

  As described above, since the semiconductor layer can be formed by a solution method, an organic semiconductor device can be manufactured at a low cost without requiring a vapor deposition process in the case of using silicon or a low molecular organic semiconductor material. In addition, since an organic semiconductor material is used, it is superior in flexibility and lightweight compared to a semiconductor device using silicon. This is also effective for application to lightweight displays, smart tags, and the like.

  A polymer compound was synthesized, a transistor element was fabricated using the polymer compound, and the characteristics were verified.

(Synthesis of Compound 1)

Bis (1,5-cyclooctadiene) di-μ-methoxydiiridium (I) (33.1 mg, 0.05 mmol), 4,4-ditertiarybutyl-2,2′-bipyridyl (13.4 mg, 0 .05 mmol) was dissolved in 150 mL of cyclohexane, and then bispinacol diborane (11.8 g, 46.6 mmol) and 1,4-dibromobenzene (5.0 g, 21.2 mmol) were added to this solution for 12 hours. Refluxed.
The solution was allowed to cool to room temperature, and extracted by adding chloroform and water.
The organic layer was washed with saturated brine and dried over magnesium sulfate.
The solvent was removed under reduced pressure, and the resulting solid was washed with methanol to obtain 6.9 g of Compound 1 (yield 67%).

The measurement results of the obtained compound 1 are shown below.
¹ H NMR (400 MHz, CDCl ₃ ): δ 7.73 (s, 2H), 1.37 (s, 24H)

(Synthesis of Compound 2)

5-Bromothiophene-3-carboxylic acid (1.0 g, 4.83 mmol), iodine (0.98 g, 3.86 mmol), and periodic acid (0.33 g, 1.45 mmol) in acetic acid (30 mL) and water (15 mL) and the mixture was stirred at 80 ° C. for 9 hours.
After allowing to cool to room temperature, sodium thiosulfate was added and stirred.
The solid was collected by filtration and washed with water to give 1.38 g of Compound 2 as a white solid (yield 86%).

The measurement results of the obtained compound 2 are shown below.
¹ H NMR (400 MHz, CDCl ₃ ): δ 7.36 (s, 1H)

(Synthesis of Compound 3)

Compound 2 (3.5 g, 10.5 mmol) was refluxed in thionyl chloride (30 mL) for 3 hours, and then thionyl chloride was removed under reduced pressure.
To this was added 20 mL of dichloromethane, and slowly added dropwise to a pyridine solution (30 mL) of 2-decyltetradecylamine (4.45 g, 12.6 mmol) in an ice bath.
The mixture was stirred in an ice bath for 3 hours and further stirred at room temperature for 3 hours.
100 mL of diluted hydrochloric acid was added and extracted with dichloromethane.
The organic layer was washed with saturated brine and dried over magnesium sulfate.
The solvent was removed under reduced pressure, and the resulting crude product was purified by column chromatography using silica gel (mobile phase: chloroform) to obtain 4.75 g of compound 3 as a white solid (yield 68%). .

The measurement results of the obtained compound 3 are shown below.
¹ H NMR (400 MHz, CDCl ₃ ): δ 7.16 (s, 1H), 5.4 (s, 2H), 6.04 (s, 1H), 3.38 (m, 2H), 1.61 (m, 1H) 1.50-1.00 ( m, 40H), 0.90-0.86 (m, 6H).

(Synthesis of Compound 4)
Compound 1 (0.51 g, 1.03 mmol) and compound 3 (1.53 g, 2.27 mmol) were placed in a mixture of 16 mL of toluene and 5 mL of 2M aqueous potassium carbonate, and 1 drop of Aliquat 336 was added.
Further, tetrakis (triphenylphosphine) palladium (0) (60 mg, 0.05 mmol) was added and refluxed for 15 hours.
After allowing to cool to room temperature, water was added and the mixture was extracted with dichloromethane.
The organic layer was washed with saturated brine and dried over magnesium sulfate.
The solvent was removed under reduced pressure, and the resulting crude product was purified by column chromatography using silica gel (mobile phase: hexane / chloroform = 1) to obtain 163 mg of compound 4 as a white solid (yield 12). %).

The measurement results of the obtained compound 4 are shown below.
¹ H NMR (400 MHz, CDCl ₃ ): δ 7.73 (s, 2H), 7.37 (s, 2H,), 5.4 (s, 2H), 3.24 (m, 4H), 1.41 (m, 2H), 1.30- 1.00 (m, 80H), 0.90-0.86 (m, 12H).

(Synthesis of Compound 5)

Compound 4 (100 mg, 0.076 mmol), copper (I) iodide (8 mg, 0.038 mmol), and potassium carbonate (21 mg, 0.15 mmol) were added to dimethylformamide (10 mL), and 120 ° C. for 12 hours. Stir.
After allowing to cool to room temperature, water was added and the mixture was extracted with chloroform. The organic layer was washed with saturated brine and dried over magnesium sulfate.
The solvent was removed under reduced pressure, and the resulting crude product was purified by column chromatography using silica gel (mobile phase: hexane / chloroform = 1), and recrystallized using ethyl acetate to obtain 62 mg. Of 5 as a yellow solid (82% yield).

The measurement results of the obtained compound 5 are shown below.
¹ H NMR (400 MHz, CDCl ₃ ): δ 7.73 (s, 2H), 7.59 (s, 2H,), 4.36 (m, 2H), 1.98 (m, 4H), 2.00 (m, 2H) 1.50-1.20 (m, 80H), 0.90-0.86 (m, 12H).

(Synthesis of polymer compound P1)

Compound 5 (124 mg, 0.05 mmol), 5,5′-bis (trimethyltin) -2,2′-bithiophene (25 mg, 0.05 mmol), tris (dibenzylideneacetone) dipalladium (0) (0.9 mg , 2 μmol), and tri (ortho-tolylphosphine) (1.2 mg, 8 μmol) were added to 2 mL of chlorobenzene and stirred using a microwave reactor (200 ° C., 10 minutes).
After allowing to cool to room temperature, the reaction solution was added to 200 mL of methanol containing 5 mL of hydrochloric acid and stirred for 6 hours. The precipitate was collected by filtration and washed with methanol, hexane, and chloroform using a Soxhlet extractor.
Further, extraction with chlorobenzene and reprecipitation in methanol were performed in the same manner to obtain 34 mg of the polymer compound P1 as a red solid (yield 59%).
The number average molecular weight calculated by GPC (Gel Permeation Chromatography) was 280000, the weight average molecular weight was 98100, and the degree of dispersion was 3.5.

(Evaluation of transistor element using polymer compound P1)
The n-type silicon substrate doped with a high concentration having a 200 nm silicon oxide film to be a gate electrode was sufficiently washed, and then the silicon oxide film surface of the substrate was subjected to silane treatment using perfluorodecyltrichlorosilane.
The polymer compound P1 was dissolved in orthodichlorobenzene to prepare a 2 g / L solution, and a polymer compound P1 thin film having a thickness of about 50 nm was produced on the surface-treated substrate by spin coating.
This thin film was heated at 150 ° C. for 30 minutes in a nitrogen atmosphere.
Next, gold was vacuum-deposited to produce a source electrode and a drain electrode having a channel length of 50 μm and a channel width of 1.5 mm on the polymer thin film.

The transistor characteristics were measured by changing the gate voltage V _G to 20 to −60 V and the source-drain voltage V _SD to 0 to −60 V to the manufactured transistor element. FIG. 1 shows transfer characteristics, and FIG. 2 shows output characteristics. From these characteristics, the hole mobility of the transistor element was calculated to be 0.03 cm ² / Vs, and the current on / off ratio was calculated to be about 10 ⁶ .

  Since the organic semiconductor material according to the present invention forms a highly oriented molecular arrangement, easily causes electron transfer due to hopping between polymer main chains, and can exhibit good charge mobility, an organic semiconductor device such as a field effect transistor Expected to be used in

Claims (3)

Containing a polymer compound having a skeleton represented by Formula 1A or Formula 1B;
An organic semiconductor material characterized by the above.
(In Formula 1A and Formula 1B, Z independently represents oxygen, sulfur or selenium, and R independently represents hydrogen or an alkyl group.) Containing a polymer compound represented by Formula 2A or Formula 2B,
An organic semiconductor material characterized by the above.
(In Formula 2A and Formula 2B, Z represents oxygen, sulfur, or selenium each independently, R represents hydrogen or an alkyl group each independently, Y represents the structure represented by Formula 3, and m is 0 or more. Represents an integer, and n represents a positive real number.)
(Wherein, W represents carbon or nitrogen. In the case of carbon, W has any of hydrogen, halogen, alkyl group, alkoxy group, alkoxycarbonyl group or alkylcarbonyl group as a substituent, and Ar is a divalent group. Represents a heterocyclic group, and l and r each independently represents an integer of 0 or more.) Containing the organic semiconductor material according to claim 1 or 2,
An organic semiconductor device characterized by that.