JP4741938B2 - Organic semiconductor device material, organic semiconductor device and organic transistor - Google Patents

Description

The present invention relates to an organic semiconductor device and an organic transistor using an organic semiconductor device material and the organic semiconductor device material as the semiconductor layer, and particularly the organic semiconductor device material comprising a polyacetylene-based conjugated polymer having a specific structural unit and, the organic semiconductor device material relates organic semiconductor device and an organic transistor using an organic semiconductor layer.

In recent years, research on organic semiconductor materials has been vigorously advanced, and applications to organic EL, dye-sensitized solar cells, organic transistors, and the like are being studied. These organic semiconductor devices are low in cost and are expected to greatly reduce the manufacturing cost of organic semiconductor devices by applying a low-cost element manufacturing process such as a solution process typified by a printing method. Furthermore, it is possible to manufacture a flexible device that is light and flexible, which is difficult with conventional silicon compound semiconductors.

A solution process, which is a low-cost device manufacturing process, is suitable for manufacturing such organic semiconductor devices, and organic semiconductor materials having excellent solubility in organic solvents are being actively developed (Non-patent Documents). 1).
Polyacetylene, which is a typical conjugated polymer, is known to have an excellent property of exhibiting very high conductivity by doping with iodine or the like, and is expected to be applied to various organic semiconductor devices. However, they are not practically used industrially because they are difficult to mold because they are not soluble in organic solvents at all, and have poor stability in air.

Non-Patent Document 2 reports the characteristics of an organic transistor using polyacetylene, which is obtained by dissolving a highly soluble polyacetylene precursor polymer in a solvent and spin-coating it on a substrate surface such as glass or silicon. A thin film is formed by producing polyacetylene by heat treatment to form an organic transistor element, and the problem of solubility in solvents can be avoided, but the heat treatment is necessary, so the printing process is complicated and the manufacturing cost However, there is a problem that it is expensive and accompanied by by-production of fluorine-based waste.

Supervised by Tatsuo Taniguchi, “Application development of organic semiconductors”, CMC Publishing, published in October 2003 Nature 335, 137 (1988)

The present invention is an organic semiconductor device material having excellent carrier mobility and stability in the air, and can be manufactured by a solution process such as printing or coating using the organic semiconductor device material for an organic semiconductor layer. It is to provide an organic semiconductor device and an organic transistor which are excellent in.

As a result of intensive studies to solve the above problems, the present inventors have found that a specific structure, that is, a polyacetylene-based conjugated polymer having a specific ring structure in the main chain has excellent characteristics as a material for organic semiconductor devices. As a result, the present invention has been completed.
That is, the present invention
(1) Providing an organic semiconductor device material including a polyacetylene-based conjugated polymer having a structural unit represented by at least the following general formula (1) and / or general formula (2).

（一般式（１）及び一般式（２）中、Ｒ^１は炭素原子数１〜１０のアルキル基から選ばれる少なくとも１種以上である。）
（２）前記（１）に記載のポリアセチレン系共役ポリマーを含む有機半導体デバイス用材料を有機半導体層として用いる有機半導体デバイス及び有機トランジスタを提供することである。

(In the general formula (1) and the formula (2), ^{R 1} is at least one selected et or alkyl group having 1 to 10 carbon atoms.)
(2) To provide an organic semiconductor device and an organic transistor using the organic semiconductor device material containing the polyacetylene-based conjugated polymer according to (1) as an organic semiconductor layer.

ADVANTAGE OF THE INVENTION According to this invention, the material for organic-semiconductor devices containing the polyacetylene type conjugated polymer excellent in carrier mobility and the stability in the air can be obtained. Further, an organic semiconductor device and an organic transistor the organic semiconductor devices for material used in an organic semiconductor layer, easily in a solution process of printing and coating, etc., yet can be manufactured at low cost, industrially extremely valuable is there.

Hereinafter, polyacetylene conjugate polymer according to the present invention, the organic semiconductor device material containing the polyacetylene conjugate polymer and is described in detail organic semiconductor device and an organic transistor using the organic semiconductor device material for the organic semiconductor layer.

  The polyacetylene-based conjugated polymer according to the present invention has at least a 6-membered ring structural unit represented by the general formula (1) and / or a 5-membered ring structural unit represented by the general formula (2) in the molecular structure. .

（一般式（１）及び一般式（２）中、Ｒ^１は炭素原子数１〜１０のアルキル基から選ばれる少なくとも１種以上である。）
一般式（１）及び一般式（２）中、Ｒ^１で表される置換基としては、好ましくは炭素原子数１〜１０の直鎖状または分枝状アルキル基から選ばれる１種以上、さらに好ましくは、炭素原子数１〜６の直鎖状または分枝状アルキル基から選ばれる１種以上であり、特に、炭素原子数１〜４の直鎖状または分枝状アルキル基であることが好ましい。
また、置換基Ｒ^１ の炭素原子数が１０以下であると、ポリマー分子間のキャリア移動が抑制されることがなく、良好な有機トランジスタ特性を得ることができる。
本発明のポリアセチレン系共役ポリマー中に含まれる一般式（１）及び／または一般式（２）で表される構造単位の割合に特に制限は無く、一般式（１）又は一般式（２）のみから形成されていてもよく、また一般式（１）及び一般式（２）で表わされる構造単位の両者が存在していても良い。本発明のポリアセチレン系共役ポリマー中の一般式（１）で表わされる構造単位は０〜１００モル％、好ましくは１〜９９モル％、さらに好ましくは５〜９５モル％、また一般式（２）で表わされる構造単位は０〜１００モル％、好ましくは１〜９９モル％、さらに５〜９５モル％であることが好ましい。
また、本実施形態におけるポリアセチレン系共役ポリマーは、一般式（１）及び一般式（２）中、Ｒ ^１ で表される置換基が、炭素原子数１〜１０の直鎖状または分枝状アルキルエーテル基及び、炭素原子数１〜２０の芳香族含有アルキル基から選ばれる１種以上、さらに好ましくは、炭素原子数１〜６の直鎖状または分枝状アルキルエーテル基及び、炭素原子数１〜１０の芳香族含有アルキル基から選ばれる１種以上であるポリマーをさらに含んでもよい。

(In the general formula (1) and the formula (2), ^{R 1} is at least one selected et or alkyl group having 1 to 10 carbon atoms.)
In the general formula (1) and the general formula (2), the substituents represented by R ^1, 1 or more preferably selected et al or a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably, at least one selected et al or a linear or branched alkyl group having 1 to 6 carbon atoms, in particular, is a straight-chain or branched alkyl group having 1 to 4 carbon atoms It is preferable.
Further, when the carbon atom number of the substituent R ¹ is 10 or less, without the carrier movement between the polymer molecules is reduced, it is possible to obtain a good organic transistor characteristics.
The ratio of the structural unit represented by the general formula (1) and / or the general formula (2) contained in the polyacetylene-based conjugated polymer of the present invention is not particularly limited, and only the general formula (1) or the general formula (2). Both of the structural units represented by the general formula (1) and the general formula (2) may be present. The structural unit represented by the general formula (1) in the polyacetylene-based conjugated polymer of the present invention is 0 to 100 mol%, preferably 1 to 99 mol%, more preferably 5 to 95 mol%, and the general formula (2). The structural unit represented is 0 to 100 mol%, preferably 1 to 99 mol%, more preferably 5 to 95 mol%.
Further, in the polyacetylene-based conjugated polymer in the present embodiment, in the general formula (1) and the general formula (2), the substituent represented by R ¹ is a linear or branched alkyl having 1 to 10 carbon atoms. One or more selected from an ether group and an aromatic-containing alkyl group having 1 to 20 carbon atoms, more preferably a linear or branched alkyl ether group having 1 to 6 carbon atoms and 1 carbon atom It may further include a polymer that is one or more selected from 10 to 10 aromatic-containing alkyl groups.

  Furthermore, structural units other than the general formula (1) and the general formula (2) may be included, and examples of the structural unit other than the structural units represented by the general formula (1) and the general formula (2) include acetylene and phenyl. Examples thereof include structural units obtained when a monoacetylene monomer such as acetylene is polymerized together with a diacetylene monomer that leads to the structure of general formula (1) or general formula (2). Such structural units other than general formula (1) and general formula (2) may be contained in the polyacetylene-based conjugated polymer in an amount of 90 mol% or less, preferably 30% or less.

The polyacetylene-based conjugated polymer according to the present invention uses gel permeation chromatography (GPC), dissolves the polyacetylene-based conjugated polymer in tetrahydrofuran, 830-RI and 875-UV manufactured by JASCO Corporation as a detector, and Shodexk as a column. The polystyrene-converted weight average molecular weight (Mw) measured at a flow rate of 1.0 ml / min at room temperature using −805, 804, 803, 802.5 is 1000 to 1,000,000, preferably 2000 to 300, In the range of 000. Here, the weight average molecular weight and the number average molecular weight are values calibrated with polystyrene standards.
When the weight average molecular weight (Mw) is 1000 or more, physical properties as a polymer and semiconductor characteristics are preferable. Moreover, it is preferable that the weight average molecular weight (Mw) is 1,000,000 or less because good thin film formability and spin coat film coatability can be obtained without impairing fluidity and solubility in a solvent. Moreover, although there is no restriction | limiting in particular in molecular weight distribution (Mw / Mn), when it is 3.0 or less, favorable thin film moldability and spin coat film coating property can be obtained.
The polyacetylene-based conjugated polymer according to the present invention has a 5% decomposition temperature in air of 150 to 450 ° C, preferably 200 to 450 ° C, as measured with a thermogravimetric apparatus (TGA). When the decomposition temperature in the air is 150 ° C. or higher, the polymer is hardly deteriorated in the air and can be applied to a printing method in the air.

  The polyacetylene-based conjugated polymer according to the present invention can be synthesized by a known method using a diacetylene monomer or a mixture of a diacetylene monomer and a monoacetylene monomer. That is, it can be obtained by polymerizing a diacetylene monomer or a mixture of a diacetylene monomer and a monoacetylene monomer using a ring-closing metathesis catalyst, preferably a living ring-closing metathesis catalyst.

As the polymerization catalyst used in the present invention, any catalyst capable of ring-closing metathesis polymerization may be used, but tungsten-based alkylidene catalyst, molybdenum-based alkylidene catalyst, rhenium-based alkylidene catalyst, tantalum-based alkylidene catalyst, ruthenium-based alkylidene. Examples thereof include a catalyst and a titanacyclobutane catalyst. The above ring-closing metathesis catalysts may be used alone or in combination of two or more.
In addition to the above, a ring-closing metathesis catalyst system comprising a combination of an organic transition metal complex and a Lewis acid as a cocatalyst, for example, transition metal halogen complexes such as molybdenum pentachloride, tungsten hexachloride, niobium pentachloride, tantalum chloride And a ring-closing metathesis catalyst comprising an organoaluminum compound, an organotin compound, or an organometallic compound such as lithium, sodium, magnesium, zinc, cadmium, or boron can be used as a cocatalyst. Catalysts described in Japanese Patent No. -73572 can be used.

In the ring-closing metathesis polymerization, the molar ratio of the acetylene monomer to the ring-closing metathesis catalyst is such that the transition metal alkylidene catalyst such as tungsten, molybdenum, rhenium, tantalum or ruthenium or the titanacyclobutane catalyst is 1 mol of the acetylene monomer. The range is 3 to 5000 mol, preferably 10 to 1000 mol.
In the case of a ring-closing metathesis catalyst comprising an organic transition metal halogen complex, transition metal halide or transition metal oxide, and an organometallic compound, the acetylene monomer is 1 mole of the organic transition metal halogen complex, transition metal halide or transition metal oxide. The organic metal compound as a co-catalyst is 0.1 to 0.1 mol per 1 mol of the organic transition metal halide complex, transition metal halide or transition metal oxide. It is preferably in the range of -10 mol, more preferably 1-5 mol.

In the present invention, when polymerizing using a ring-closing metathesis catalyst, it is preferable to polymerize in the presence of a chain transfer agent such as olefin or diene in order to increase the catalyst efficiency. These olefins or dienes may be used alone or in combination of two or more. May be used in combination.
The amount of the olefin used together is 0.001 to 1000 mol, preferably 0.01 to 100 mol, per 1 mol of the acetylene monomer.
In addition, the ring-closing metathesis polymerization may be a solvent-free or a solvent, but particularly used solvents include cyclic ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbons such as benzene, toluene, xylene or ethylbenzene, acetone, Examples include aliphatic ketones such as methyl ethyl ketone, aliphatic esters such as methyl acetate and ethyl acetate, and halogenated hydrocarbons such as methylene dichloride, chloroform, dichloroethane, dichloroethylene, tetrachloroethane, chlorobenzene, and trichlorobenzene. You may mix and use the above.

In the ring-closing metathesis polymerization, the monomer concentration is preferably in the range of 0.1 to 50% by mass, and the polymerization reaction is carried out at −40 ° C. to 120 ° C., depending on the reactivity of the monomer and the solubility in the polymerization solvent. However, it is preferable to carry out at 20 to 80 ° C.
The reaction atmosphere is preferably in an inert gas such as nitrogen or argon. After the polymerization reaction, the reaction is stopped with a deactivator such as an aldehyde such as butyraldehyde, a ketone such as acetone, or an alcohol such as methanol. Thus, a ring-closing metathesis polymer solution can be obtained.

The polyacetylene-based conjugated polymer according to the present invention may be purified as necessary. This purification can be performed by appropriately combining known methods such as general filtration, reprecipitation, adsorption with an adsorbent, and liquid separation extraction.
The metal content contained in the polyacetylene-based conjugated polymer according to the present invention is preferably 1000 ppm or less, more preferably 100 ppm or less.
It is preferable that the metal content is 1000 ppm or less because good characteristics as an organic transistor can be obtained.

In addition, the polyacetylene-based conjugated polymer having the structural unit represented by the general formula (1) and / or the general formula (2) constituting the material for an organic semiconductor device of the present invention is the above-described substituent represented by R ¹ . Two or more kinds of substituents may be contained, and can be obtained by copolymerizing two or more kinds of monomers having different substituents represented by R ¹ . In addition, two or more types of monomers having different substituents represented by R ¹ can be individually polymerized and blended in a specific amount to be used as a material for an organic semiconductor device .

The polyacetylene-based conjugated polymer of the present invention can be suitably used as a material for organic semiconductor devices . Specifically, the organic semiconductor device material of the present invention can be used for a light emitting layer of an organic EL and an organic light emitting diode, a laser oscillation element of an organic semiconductor laser, a photoelectric conversion layer of an organic solar cell, and the like. A transistor device that can be suitably used as a semiconductor layer of a transistor and can be driven favorably can be provided by using the organic semiconductor device material of the present invention for a semiconductor layer of an organic transistor.

  The polyacetylene-based conjugated polymer of the present invention is preferably installed as an organic semiconductor layer on a substrate by a wet film-forming method such as cast coating, spin coating, printing, and ink-jet method using a solution prepared by dissolving in a suitable solvent. In this case, the solvent for dissolving the polyacetylene-based conjugated polymer of the present invention is not limited as long as it can prepare a solution with an appropriate concentration by dissolving the polyacetylene-based conjugated polymer. Specifically, tetrahydrofuran, dioxane, etc. Cyclic ether solvents, ketone solvents such as acetone and methyl ethyl ketone, alkyl halide solvents such as chloroform and 1,2-dichloroethane, aromatic solvents such as toluene, xylene and o-dichlorobenzene, N-methylpyrrolidone, Examples include sulfolane and carbon disulfide.

  The thickness of these organic semiconductor layers is not particularly limited, but a range of 1 nm to 100 nm is preferable for obtaining an organic transistor having a large ON / OFF ratio.

As a substrate used for the organic transistor of the present invention, not only glass and silicon but also a flexible plastic sheet such as PET can be used. Further, the use of a plastic sheet can reduce the weight and improve the resistance to impact.
The organic transistor of the present invention has three types of separated electrodes, that is, a gate electrode, a source electrode, and a drain electrode, and the gate electrode is in contact with the insulating layer.

The material for each electrode is not particularly limited as long as it is a conductive material. Platinum, gold, silver, nickel, chromium, copper, indium, palladium, aluminum, molybdenum, tungsten, indium tin oxide (ITO), fluorine-doped Zinc oxide, zinc, graphite, glassy carbon, silver paste and carbon paste, lithium, beryllium, sodium, magnesium, potassium, calcium, scandium, titanium, manganese, zirconium, gallium, niobium, sodium-potassium alloy, magnesium / indium mixture, An aluminum / aluminum oxide mixture or the like is used, and platinum, gold, silver, copper, aluminum, indium and ITO are particularly preferable. In addition, known conductive polymers such as conductive polyaniline, conductive polypyrrole, and conductive polythiophene can also be used.
As a method for forming an electrode, a method for forming an electrode using a known photolithographic method or a lift-off method, using a conductive thin film formed by a method such as vapor deposition or sputtering using the above as a raw material, or a metal foil such as aluminum or copper There is a method in which a resist is formed and etched by thermal transfer, ink jet or the like.

  Further, a solution or dispersion of a conductive polymer, a conductive fine particle dispersion, or the like may be directly patterned by an ink jet method, or may be formed from a coating film by lithography or laser ablation. Furthermore, a method of patterning an ink containing a conductive polymer or conductive fine particles, a conductive paste, or the like by a printing method such as relief printing, intaglio printing, planographic printing, or screen printing can also be used.

  In the present invention, various insulating films can be used as the insulating film used for the gate insulating layer and the like, and a metal oxide film having a high relative dielectric constant is particularly preferable. Examples of metal oxides include silicon oxide, silicon nitride, aluminum oxide, tantalum oxide, titanium oxide, tin oxide, barium titanate, barium magnesium fluoride, bismuth titanate, strontium bismuth titanate, pentoxide tantalum, titanium dioxide, And trioxide yttrium. Among these, silicon oxide, silicon nitride, aluminum oxide, tantalum oxide, and titanium oxide are preferable.

  As a method for forming a metal oxide film, a dry process such as a vacuum deposition method, a molecular beam epitaxial growth method, an ion cluster beam method, a low energy ion beam method, an ion plating method, a CVD method, a sputtering method, an atmospheric pressure plasma method, And wet processes such as a spray coating method, a spin coating method, a casting method, a roll coating method, a coating method such as a bar coating method, and a patterning method such as printing and ink jetting, and can be used depending on the material. The wet process is a method of applying and drying a liquid in which fine particles of metal oxide are dispersed in an arbitrary organic solvent or water using a dispersion aid such as a surfactant as required, or an oxide precursor, for example, A so-called sol-gel method in which a solution of an alkoxide body is applied and dried is used. Among these, the atmospheric pressure plasma method and the sol-gel method are preferable.

An organic compound film used for the insulating layer can also be used, and examples thereof include polyimide, polyamide, polyester, polyacrylate, photo radical polymerization type, photo cationic polymerization type photo curable resin, polyvinyl phenol, polyvinyl alcohol. And novolak resin. As a method of forming the organic compound film, a solution process is preferable.
Moreover, a metal oxide film and an organic oxide film can be laminated and used together. The thickness of these insulating films is generally 50 nm to 3 μm, preferably 100 nm to 1 μm.
As a method for applying the composition of each layer, a known application method such as dipping, spin coating, bar coating, blade coating, squeeze coating, curtain coating, spray coating or the like can be used.

The carrier mobility of the organic transistor using the polyacetylene-based conjugated polymer of the present invention as a semiconductor layer is 1 × 10 ⁻⁵ cm ² / Vs or more, preferably 1 × 10 ^{−5 to} 1 cm ² / Vs, more preferably 1 × 10. ⁻⁵ to 1 × 10 ⁻² cm ² / Vs, more preferably 1 × 10 ⁻⁵ to 1 × 10 ⁻³ cm ² / Vs. When the carrier mobility is 1 × 10 ⁻⁵ cm ² / Vs or more, it is preferable because it shows an effective performance as an organic transistor.
The ON / OFF ratio of the organic transistor using the polyacetylene conjugated polymer of the present invention for the semiconductor layer is 100 or more, preferably 100 to 100,000, more preferably 100 to 10,000, and more preferably 100 to 10,000. When the ON / OFF ratio is 100 or more, it is preferable because effective performance as an organic transistor is exhibited.

When the organic semiconductor device material according to the present invention is used, an organic transistor having excellent semiconductor characteristics can be obtained by a simple solution process. Further, by using the organic transistor of the present invention, the switching element can be formed on a lightweight and flexible substrate, and various electronic devices, that is, a display such as a flexible sheet display and electronic paper, a plastic IC card, a smart card, an RFID tag, etc. Application devices such as electronic devices and large screen image sensors can be lightweight, thin, and flexible.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In addition, the physical-property value and characteristic evaluation of the polymer obtained in the Example were performed with the following method.

(1) Using average molecular weight gel permeation chromatography (GPC), the obtained polyacetylene-based conjugated polymer was dissolved in tetrahydrofuran, 830-RI and 875-UV manufactured by JASCO Corporation as a detector, and Shodexk-805 as a column. Measured at a flow rate of 1.0 ml / min at room temperature using 804, 803, 802.5 and determined as the molecular weight calibrated by polystyrene standards.

(2) Ratio of structural units represented by general formula (1) and general formula (2) in the polymer
¹³ C-NMR spectrum was measured, and the ratio of the integrated value of the carbonyl carbon of the structural unit represented by the general formula (1) of 171 ppm and the carbonyl carbon of the structural unit represented by the general formula (2) of 170 ppm was determined. Were determined.

(3) 5% decomposition temperature in air About 5-10 mg of polyacetylene conjugated polymer is weighed in an aluminum pan, and air flow rate is 50 ml / min, using a thermogravimetric measuring device DTG-60A manufactured by Shimadzu Corporation. Measurement was performed at a rate of 10 ° C./min, and the temperature at which the weight decreased by 5% from the sample weight at the start of measurement was defined as the 5% decomposition temperature in air.

(4) Characteristic evaluation of organic transistor The performance of the organic transistor was evaluated under vacuum using a semiconductor characteristic evaluation apparatus.
The carrier mobility (μ) was calculated according to the following equation (1) from the data in the saturation region (gate voltage, VG <source-drain voltage, VSD).

ISD = Ciμ (W / 2L) (VG−VT) ² (1)
Where ISD is the drain current in the saturation region, W and L are the width and length of the semiconductor channel, respectively, Ci is the capacitance per unit area of the gate dielectric layer, and VG and VT are respectively , Gate voltage and threshold voltage. The VT of this device was obtained from the relationship between the square root of the ISD in the saturation region and the VG of the device obtained by extrapolating ISD = 0 from the measurement data.

  The ON / OFF ratio is a ratio of the minimum saturated source-drain current ISD and the maximum saturated source-drain current ISD when the gate voltage VG is changed. Here, when the drain voltage is set to -50V The ratio of the current that flows when VG = 0V (OFF current) and the current that flows when VG = -50V (ON current) is used.

[Example 1]
(Monomer synthesis)
Under a nitrogen stream, 13.3 g (305 mmol) of sodium hydride (55% mineral oil suspension) was weighed into a 500 ml three-necked flask, and 400 ml of dry tetrahydrofuran was added to form a slurry. To this, 23.2 g (145 mmol) of diethyl malonate was added dropwise at room temperature for 30 minutes and stirred until hydrogen evolution ceased (about 30 minutes), and then 50 g (336 mmol) of an 80% toluene solution of propargyl bromide was added at room temperature, 1 Dropped in 5 hours. After completion of dropping, the mixture was stirred at room temperature for 16 hours. 100 ml of distilled water was added and the organic layer was extracted with pentane. Magnesium sulfate was added to the organic layer and dried, the magnesium sulfate was filtered off, and the solvent was distilled off under reduced pressure. The obtained brown oil was purified by silica gel column chromatography (solvent: hexane, hexane: ethyl acetate = 90: 10), and the obtained pale yellow transparent liquid was recrystallized from hexane to give diethyl dipropargylmalonate 24. 5 g (72%) were obtained.
^{[1 H-NMR (CDCl3,} δ ppm) 4.21 (q, 4H), 2.97 (d, 2H), 2.00 (t, 2H), 1.23 (t, 6H)]

(Synthesis of polyacetylene-based conjugated polymer)
In a glove box, 1 g (4.2 mmol) of diethyl dipropargylmalonate was weighed into a 20 ml sample bottle and dissolved in 30 ml of dimethoxyethane. While stirring the solution, the monomer / catalyst = 50/1 to become so as a ring-closing metathesis catalyst _{Mo (N-2,6-iPr 2} C 6 H 3) (CHC (Me) 2 C 6 H 5) (OC (CF ₃ ) ₂ Me) ₂ (wherein iPr represents an iso-propyl group) 65 mg (85 μmol) was added, and the mixture was stirred at room temperature for 10 minutes. After stopping the reaction by adding 20 mg of n-propylaldehyde, the mixture was stirred for 1 hour. This ring-closing metathesis polymer solution was added to methanol to precipitate the ring-closing metathesis polymer, which was filtered, washed with methanol, and dried under vacuum to obtain 950 mg (yield 95%) of a purple powdery polyacetylene polymer.
[1H-NMR (CDCl3, δ, ppm) 6.9-5.6 (bm, 2H), 4.2 (m, 4H), 3.6-2.8 (bm, 2H), 1.2 ( m, 6H)]
The weight average molecular weight (Mw) of the obtained polymer was 18,700, the number average molecular weight (Mn) was 16,500, the molecular weight distribution (Mw / Mn) was 1.13, and the 5% decomposition temperature in air was 325 ° C. It was. The proportion of the structural unit represented by the general formula (1) in the polymer determined from the integral ratio of the carbonyl carbon in the ¹³ C-NMR spectrum (FIG. 1) was 51 mol%, and the proportion of the structural unit represented by the general formula (2). The ratio was 49 mol%.

(Characteristic evaluation of organic transistors)
A silicon thermal oxide film having a thickness of 300 nm is formed as an insulating layer on a heavily doped silicon substrate to be a gate electrode, and then an organic semiconductor having a thickness of about 100 nm is formed by spin coating the chloroform solution of the polymer obtained in Example 1. A thin film was formed. Gold was deposited on the surface of this film using a mask to form source and drain electrodes. Thus, an organic transistor element (a schematic diagram of the element is shown in FIG. 2) having a channel length of 30 μm and a channel width of 5 mm was produced. The voltage between 0V and -50V is applied between the source and drain of this organic transistor element, the current between the source and drain when the gate voltage is changed in the range of 0V to -50V is measured, and the carrier is determined according to the equation (1). When the mobility (μ) was calculated, it was 2.4 × 10 ⁻⁵ cm ² / V · s, and the ON / OFF ratio was 5.0 × 10 ² .

[Example 2]
The molar ratio of catalyst to monomer (catalyst / monomer) An experiment was carried out in the same manner as in Example 1 except that the amount of catalyst was changed to 1/500 to obtain a polyacetylene-based conjugated polymer. The weight average molecular weight (Mw) is 250,000, the number average molecular weight (Mn) is 208000, the molecular weight distribution (Mw / Mn) is 1.20, the 5% decomposition temperature in air is 324 ° C., and the general formula ( The proportion of the structural unit represented by 1) was 53 mol%, and the proportion of the structural unit represented by the general formula (2) was 47 mol%. Using this polymer, an organic transistor element was produced in the same manner as in Example 1, and the organic transistor characteristics were measured. The carrier mobility (μ) was 1.9 × 10 ⁻⁵ cm ² / V · s. The ON / OFF ratio was 4.0 × 10 ² .

[Example 3]
The experiment was performed in the same manner as in Example 1 except that the catalyst was changed to Mo (N-2,6-iPr ₂ C ₆ H ₃ ) (CHC (Me) ₂ C ₆ H ₅ ) (OC (CH ₃ ) ₃ ) _2. And a polyacetylene-based conjugated polymer was obtained.
The weight average molecular weight (Mw) is 33000, the number average molecular weight (Mn) is 28700, the molecular weight distribution (Mw / Mn) is 1.15, the 5% decomposition temperature in air is 326 ° C., and the general formula ( The proportion of the structural unit represented by 1) was 12 mol%, and the proportion of the structural unit represented by the general formula (2) was 88 mol%. Using this polymer, an organic transistor element was produced in the same manner as in Example 1 and measured for organic transistor characteristics. The carrier mobility (μ) was 1.1 × 10 ⁻⁵ cm ² / V · s. The ON / OFF ratio was 2.0 × 10 ² .

[Example 4]
(Monomer synthesis)
Synthesis was performed in the same manner as above except that diethyl malonate was changed to dimethyl malonate to synthesize dimethyl dipropargylmalonate.
^{[1 H-NMR (CDCl3,} δ ppm) 4.20 (s, 6H), 2.97 (d, 2H), 2.00 (t, 2H)]

(Synthesis of polyacetylene-based conjugated polymer)
An experiment was conducted in the same manner as in Example 1 except that the monomer was changed from diethyl dipropargylmalonate to dimethyl dipropargylmalonate to obtain a polyacetylene-based conjugated polymer. The weight average molecular weight (Mw) is 19800, the number average molecular weight (Mn) is 14700, the molecular weight distribution (Mw / Mn) is 1.35, the 5% decomposition temperature in air is 343 ° C., and the general formula ( The proportion of the structural unit represented by 1) was 50 mol%, and the proportion of the structural unit represented by the general formula (2) was 50 mol%.

(Characteristic evaluation of organic transistors)
Using the obtained polymer, an organic transistor element was produced in the same manner as in Example 1, and the organic transistor characteristics were measured. The carrier mobility (μ) was 2.5 × 10 ⁻⁵ cm ² / V · s. The ON / OFF ratio was 6.0 × 10 ² .

[Comparative Example 1]
Under a nitrogen _{atmosphere, Mo (N-2,6-iPr} 2 C 6 H 3) (CHC (Me) 2 C 6 H 5) (OC (CF 3) 2 Me) 2 (iPr in the formula iso- propyl When a 50 mg equivalent of acetylene gas was blown into the catalyst while stirring 30 ml of a 65 mg (85 μmol) dimethoxyethane solution at room temperature, a black precipitate was deposited. After stopping the reaction by adding 20 mg of n-propylaldehyde, the mixture was stirred as it was for 1 hour. The reaction solution was filtered with a glass filter, and the precipitated polyacetylene was collected by filtration and washed with pentane. The obtained polyacetylene was completely insoluble in various organic solvents such as tetrahydrofuran, toluene and chloroform.

[Comparative Example 2]
(Monomer synthesis)
To 500 ml of ether, 24.9 g (134 mmol) of n-dodecanol and 14.9 g (147 mmol) of triethylamine were added and cooled in an ice bath. To this was added dropwise 40 ml of an ether solution of 9.2 g (65 mmol) of malonic dichloride over 2 hours. After completion of the dropwise addition, the ice bath was removed, the temperature was returned to room temperature, and the mixture was stirred overnight. After stirring, the reaction mixture was washed with 10% sulfuric acid and then with water, and the obtained organic layer was dried and concentrated to obtain a red liquid containing the desired product. Methanol was added thereto and recrystallization was performed to obtain 12 g (yield 42%) of di-n-dodecyl malonate as a light pink solid. Using this in place of diethyl malonate, di-propargyl malonate di-n-dodecyl was synthesized in the same manner as in Example 1.
[ ¹ H-NMR (CDCl 3, δ ppm) 4.13 (t, 4 H), 2.98 (d, 4 H), 2.00 (t, 2 H), 1.59 (m, 4 H), 1.23 (M, 36H), 0.86 (m, 6H)]

(Synthesis of polyacetylene-based conjugated polymer)
An experiment was conducted in the same manner as in Example 1 except that the monomer was changed from diethyl dipropargylmalonate to di-n-dodecyl dipropargylmalonate to obtain a polyacetylene-based conjugated polymer. The weight average molecular weight (Mw) is 20800, the number average molecular weight (Mn) is 17800, the molecular weight distribution (Mw / Mn) is 1.17, the 5% decomposition temperature in air is 330 ° C., and the general formula ( In 1), the proportion of the structural unit having 12 carbon atoms in the substituent represented by R ¹ is 44 mol%, and the structural unit having 12 carbon atoms in the substituent represented by R ¹ in the general formula (2) The ratio was 56 mol%.

(Characteristic evaluation of organic transistors)
Using the obtained polymer, an organic transistor element was produced in the same manner as in Example 1, and the organic transistor characteristics were measured. No transistor characteristics were observed.

[Comparative Example 3]
An experiment was conducted in the same manner as in Example 1 except that the monomer was changed from diethyl dipropargylmalonate to phenylacetylene to obtain a polyacetylene-based conjugated polymer. The weight average molecular weight (Mw) was 7,500, the number average molecular weight (Mn) was 5600, the molecular weight distribution (Mw / Mn) was 1.34, and the 5% decomposition temperature in air was 278 ° C. Using this polymer, an organic transistor element was produced in the same manner as in Example 1, and the organic transistor characteristics were measured. No transistor characteristics were observed.

From these results, it was shown that the organic semiconductor device material containing the polyacetylene-based conjugated polymer of the present invention suitably functions as a semiconductor layer of an organic transistor.

The organic transistor using the polyacetylene-based conjugated polymer of the present invention as an organic semiconductor layer is lightweight and flexible, and various electronic devices, that is, a flexible sheet display, an organic EL, an electronic paper display, a plastic IC card, a smart card, an RFID It can be suitably used for portable electronic devices such as tags and large screen image sensors.

¹³ C-NMR spectrum measured in CDCl 3 of the polymer of Example 1. The schematic diagram of the element which evaluated the transistor characteristic.

Explanation of symbols

1 Source electrode (thickness 400nm)
2 Drain electrode (thickness 400nm)
3 Gate electrode (silicon substrate)
4 Organic semiconductor layer (100 nm thick)
5 Insulating layer (SiO ₂ ) (thickness 300 nm)

Claims (9)

An organic semiconductor device material comprising a polyacetylene-based conjugated polymer having at least a structural unit represented by the following general formula (1) and / or general formula (2).

(In General Formula (1) and General Formula (2), R ¹ is at least one selected from alkyl groups having 1 to 10 carbon atoms.) The substituent R ¹ in the general formula (1) and the general formula (2) is at least one selected from a linear or branched alkyl group having 1 to 6 carbon atoms. The material for organic semiconductor devices as described. The organic semiconductor device material according to claim 1 or 2, wherein the polyacetylene-based conjugated polymer has a molecular weight of 1,000 or more and 1,000,000 or less. The organic-semiconductor device using the organic-semiconductor-device material as described in any one of Claims 1 thru | or 3. The organic-semiconductor device of Claim 4 manufactured by the solution process. The organic transistor which uses the organic-semiconductor device material as described in any one of Claims 1 thru | or 3 as an organic-semiconductor layer. The organic transistor according to claim 6, wherein the organic semiconductor layer is formed using a solution process. 8. The organic transistor according to claim 6, wherein the carrier mobility is 1 × 10 ⁻⁵ cm ² / Vs or more. ON / OFF ratio is 100 or more, the organic transistor as claimed in any one claims 6 to 8.

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