JP5190784B2 - Polymer - Google Patents

Description

  The present invention provides a polymer having a novel structural unit, and further relates to an organic electronic material having excellent solubility necessary for carrying out a simple liquid film forming process.

  In recent years, research and development on organic electronic devices using organic semiconductor materials has been active. Organic semiconductor materials can be easily formed into a thin film by a simple method using a wet process such as a printing method or a spin coating method, and the manufacturing process temperature can be lowered as compared with a thin film transistor using a conventional inorganic semiconductor material. There are advantages. This enables formation on plastic substrates with generally low heat resistance, which can realize weight reduction and cost reduction of electronic devices such as displays, and various developments such as applications that take advantage of the flexibility of plastic substrates. Can be expected.

So far, acene-based materials such as pentacene have been reported as organic semiconductor materials (see, for example, Patent Document 1). Organic thin-film transistors using pentacene as an organic semiconductor layer have been reported to have relatively high mobility, but these acene-based materials have extremely low solubility in general-purpose solvents, and they are used as active layers in organic thin-film transistors. When a thin film is formed, it is necessary to go through a vacuum deposition process. Therefore, it does not meet the expectation for an organic semiconductor material that a thin film can be formed by a simple process such as coating and printing as described above.
Moreover, poly (3-alkyl thiophene) (refer nonpatent literature 1) etc. are proposed as a polymeric organic-semiconductor material. Since these polymer organic semiconductor materials have low solubility due to the introduction of regioselective alkyl groups, they can be thinned by coating or printing without going through a vacuum deposition process.

  On the other hand, for stable operation as an organic electronic device, oxidation stability of an organic semiconductor material is required. Although the poly (3-alkylthiophene) can form a thin film by a simple process such as coating or printing, it is easily oxidized due to its low ionization potential. The operation at was unstable.

  In addition, polythiophenes having improved oxidation stability of the poly (3-alkylthiophene) have been proposed (see Patent Document 2 and Patent Document 3). However, although the organic semiconductor material disclosed in Patent Document 2 also has solubility, the molecular weight dependency of mobility is large, and in order to have high mobility, a higher molecular weight polymer is necessary. As a result, the solubility becomes very low, and there is a problem that there is a limitation in application to simple thin film formation processes such as coating and printing.

JP-A-5-55568 JP 2003-221434 A JP 2003-268083 A Synth. Met. , 84, 269 (1997)

  The present invention has been made in view of the above-described conventional technology, and provides a polymer useful as a material for organic electronics, which is highly soluble in general-purpose solvents and can be applied to a low-cost process capable of wet film formation. For the purpose.

As a result of intensive studies, the present inventors have found that the above problems can be solved by a polymer containing a specific structural unit, and have reached the present invention.
That is, the present invention is shown by the following (1) and (2).

（Ａｒ_１およびＡｒ_２は置換又は無置換の芳香族炭化水素基の２価基であり、
Ｒ_１は置換又は無置換のアルキレン基であり、
ｎは１以上の整数であり、
Ｒ_２は、置換又は無置換のアルキル基、置換又は無置換のアルコキシ基、及び置換又は無置換のアルキルチオ基からなる群より選択される基であり、
ｘは０から２までの整数を表し、
ｎが１、かつ、ｘが２である場合のＲ_２は同一でも別異でもよく、
ｎが２以上の場合、それぞれのＲ_２は互いに同一でも異なっていてもよく、ｎが２以上のときそれぞれのｘは同一でも別異でもよい。）
（２）前記一般式（Ｉ）で表される繰返し単位を有する重合体が、下記一般式（II）で表されることを特徴とする上記（１）記載の繰返し単位を有する重合体。

（Ｒ_１は置換または無置換のアルキレン基であり、
ｎは１以上の整数であり、
Ｒ_２、Ｒ_３およびＲ_４は置換又は無置換のアルキル基、置換又は無置換のアルコキシ基、及び置換又は無置換のアルキルチオ基からなる群より選択される基であり、
ｘは０から２までの整数を表し、
ｎが１、かつ、ｘが２である場合のＲ_２は同一でも別異でもよく、
ｎが２以上の場合、それぞれのＲ_２は互いに同一でも異なっていてもよく、
ｎが２以上のときそれぞれのｘは同一でも別異でもよく、
ｙおよびｚはそれぞれ０から４までの整数を表し、同一でも別異でもよい。） (1) A polymer containing a structural unit represented by the following general formula (I).

(Ar ₁ and Ar ₂ are a divalent group of a substituted or unsubstituted aromatic hydrocarbon group,
R ₁ is a substituted or unsubstituted alkylene group,
n is an integer of 1 or more,
R ₂ is a group selected from the group consisting of a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted alkylthio group;
x represents an integer from 0 to 2,
R ₂ when n is 1 and x is 2 may be the same or different,
When n is 2 or more, each R ₂ may be the same or different, and when n is 2 or more, each x may be the same or different. )
(2) The polymer having a repeating unit according to the above (1), wherein the polymer having the repeating unit represented by the general formula (I) is represented by the following general formula (II).

(R ₁ is a substituted or unsubstituted alkylene group,
n is an integer of 1 or more,
R ₂ , R ₃ and R ₄ are groups selected from the group consisting of substituted or unsubstituted alkyl groups, substituted or unsubstituted alkoxy groups, and substituted or unsubstituted alkylthio groups,
x represents an integer from 0 to 2,
R ₂ when n is 1 and x is 2 may be the same or different,
when n is 2 or more, each R ₂ may be the same as or different from each other;
When n is 2 or more, each x may be the same or different,
y and z each represents an integer of 0 to 4, and may be the same or different. )

  Since the polymer of the present invention is soluble in an organic solvent, it can be deposited at low cost, and is useful as a material for organic electronics such as a charge transporting polymer material for an organic transistor.

The manufacturing method of the polymer of this invention is demonstrated below.
Examples of the reaction for producing the polymer of the present invention represented by the general formula (I) or the general formula (II) include Suzuki coupling using an aryl halide and an aryl boron compound, and an aryl halogen and an aryl tin compound. Cross coupling reaction such as Still Coupling using is preferred.
The halogen atom of the aryl halide is preferably an iodide or bromide from the viewpoint of reactivity.

  As the aryl boron compound, aryl boronic acid or aryl boronic acid ester is used. However, the aryl boronic acid ester does not form a dianhydride (boroxine) like aryl boronic acid, and has high crystallinity and purification. Is more preferable because it is easy.

Examples of the synthesis method of the aryl boronic acid ester include the following methods (i) to (iv).
(I) A method of reacting aryl boronic acid and alkyl diol by heating in an anhydrous organic solvent (ii) A method of reacting by adding an alkoxy boron ester after metallizing the halogen moiety of the aryl halide (iii) After preparing Grignard reagent of aryl halogen, reacting by adding alkoxyboron ester (iv) Method of reacting aryl halide with bis (pinacolato) diboron or bis (neopentyl glycolato) diboron by heating under palladium catalyst

As the palladium catalyst, various catalysts such as Pd (PPh ₃ ) ₄ , PdCl ₂ (PPh ₃ ) ₂ , Pd (OAc) ₂ , PdCl ₂ or separately adding triphenylphosphine as a ligand to palladium carbon are used. However, for the most general purpose, Pd (PPh ₃ ) ₄ is used.

This reaction always requires a base, but relatively weak bases such as Na ₂ CO ₃ , NaHCO ₃ , K ₂ CO ₃ give good results. When affected by steric hindrance or the like, strong bases such as Ba (OH) ₂ and K ₃ PO ₄ are effective. Other caustic soda, caustic potash, metal alkoxide, etc., for example, potassium t-butoxide, sodium t-butoxide, lithium t-butoxide, potassium 2-methyl-2-butoxide, sodium 2-methyl-2-butoxide, sodium methoxide, sodium ethoxide , Potassium ethoxide, potassium methoxide and the like can also be used.

  Further, a phase transfer catalyst may be used to make the reaction proceed more smoothly, preferably tetraalkylammonium halide, tetraalkylammonium hydrogensulfate, or tetraalkylammonium hydroxide. -N-butylammonium halide, benzyltriethylammonium halide, or tricaprylylmethylammonium chloride.

  Examples of the reaction solvent include alcohols such as methanol, ethanol, isopropanol, butanol, 2-methoxyethanol, 1,2-dimethoxyethane, and bis (2-methoxyethyl) ether, and ether ethers, and cyclic ethers such as dioxane and tetrahydrofuran. Benzene, toluene, xylene, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like.

The reaction temperature of the polymerization reaction is appropriately set depending on the reactivity of the monomer used and the reaction solvent, but is preferably suppressed to the boiling point of the solvent or lower.
The reaction time in the polymerization reaction can be appropriately set in terms of the reactivity of the monomer used or the molecular weight of the desired polymer, and is preferably 1 to 50 hours, and more preferably 2 to 24 hours. .

It is also possible to add a molecular weight regulator in order to adjust the molecular weight in the above polymerization operation, or a sealing agent for sealing the end of the polymer as a terminal modifying group to the reaction system. It is also possible to add it. Therefore, a group based on a terminator may be bonded to the end of the polymer in the present invention.
Examples of the molecular weight regulator and the end-capping agent include compounds having one reactive group such as phenylboronic acid, bromobenzene, and iodobenzene.

  The preferred molecular weight of the polymer of the present invention is 1,000 to 1,000,000, more preferably 2000 to 500,000 in terms of polystyrene-reduced number average molecular weight. When the molecular weight is too small, the film forming property such as the generation of cracks is deteriorated and the practicality becomes poor. On the other hand, when the molecular weight is too large, the solubility in a general organic solvent is deteriorated, the viscosity of the solution becomes high and the coating becomes difficult, which is also a practical problem.

  The polymer of the present invention obtained as described above is used after removing impurities such as catalyst, base, unreacted monomer, terminal stopper, and inorganic salt generated during the polymerization. . For these purification operations, conventionally known methods such as reprecipitation, extraction, Soxhlet extraction, ultrafiltration, dialysis, adsorbent and the like can be used.

  The polymer of the present invention obtained by the above production method is prepared by a known film formation method such as spin coating method, casting method, dipping method, ink jet method, doctor blade method, screen printing method, dispensing method, spray coating, etc. It is possible to produce a good thin film free from cracks and excellent in strength, toughness, durability, etc., and can be suitably used as a polymer material for organic electronics such as a photoelectric conversion element, FET element, and light emitting element. .

Specific examples of the polymers represented by the general formulas (I) and (II) thus obtained are shown below.
The divalent groups Ar ₁ and Ar ₂ of the substituted or unsubstituted aromatic hydrocarbon group in the general formula (I) may be any of a monocyclic group and a polycyclic group (a condensed polycyclic group or a non-condensed polycyclic group). Well, the following can be mentioned as an example. Examples thereof include a phenyl group, a naphthyl group, a pyrenyl group, a fluorenyl group, an azulenyl group, an anthryl group, a triphenylenyl group, a chrycenyl group, a biphenyl group, and a terphenyl group.

These groups having a cyclic structure may have various substituents as shown below.
(1) halogen atom, trifluoromethyl group, cyano group, nitro group (2) linear or branched alkyl group or alkoxy group having 1 to 25 carbon atoms (these are further a halogen atom, cyano group, phenyl group, (It may be substituted with a hydroxyl group, a carboxyl group, an alkoxy group or an alkylthio group.)
(3) Aryloxy group (an aryloxy group having a phenyl group or a naphthyl group as the aryl group may be mentioned. These may contain a halogen atom as a substituent and are linear or branched having 1 to 25 carbon atoms. And may contain an alkyl group, an alkoxy group, or an alkylthio group, specifically, a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methylphenoxy group, or a 4-methoxyphenoxy group. , 4-chlorophenoxy group, 6-methyl-2-naphthyloxy group, etc.)
(4) Alkylthio group or arylthio group (Specific examples of the alkylthio group or arylthio group include a methylthio group, an ethylthio group, a phenylthio group, and a p-methylphenylthio group.)
(5) alkyl-substituted amino group (specifically, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (p-tolyl) amino group, dibenzylamino) Group, piperidino group, morpholino group, euroridyl group and the like.)
(6) Acyl group (Specific examples of the acyl group include an acetyl group, a propionyl group, a butyryl group, a malonyl group, and a benzoyl group.)

The polymer of the present invention may have a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group or a substituted or unsubstituted alkylthio group as a substituent on the aromatic ring, and the solvent. From the viewpoint of improving solubility, it is preferable to have a substituted or unsubstituted alkyl group, alkoxy group or alkylthio group as a substituent (R ₂ , R ₃ , R ₄ ). If the number of carbons of these substituents increases, the solubility will be improved, but on the other hand, the properties such as charge transportability will decrease, so that the desired properties can be obtained within the range where the solubility is not impaired. It is preferred to select a substituent.

  Examples of suitable substituents in that case include alkyl groups, alkoxy groups and alkylthio groups having 1 to 25 carbon atoms. A plurality of the same substituents may be introduced, or a plurality of different substituents may be introduced. These alkyl groups, alkoxy groups and alkylthio groups are further halogen atoms, cyano groups, aryl groups, hydroxyl groups, carboxyl groups, linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms, alkoxy groups or An aryl group substituted with an alkylthio group may be contained.

  Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, t-butyl group, s-butyl group, n-butyl group, i-butyl group, pentyl group, hexyl group, Heptyl group, octyl group, nonyl group, decyl group, dodecyl group, 3,7-dimethyloctyl group, 2-ethylhexyl group, trifluoromethyl group, 2-cyanoethyl group, benzyl group, 4-chlorobenzyl group, 4-methyl A benzyl group, a cyclopentyl group, a cyclohexyl group, etc. can be mentioned as an example. As an alkoxy group or an alkylthio group, an oxygen atom or a sulfur atom is inserted at the bonding position of the alkyl group to form an alkoxy group or an alkylthio group, respectively. Is given as an example.

Specific examples of the alkylene group R ₁ include a methylene group, an ethylene group, an n-propylene group, an i-propylene group, an n-butylene group, a t-butylene group, an s-butylene group, an i-butyl group, and a pentylene group. Examples thereof include hexylene group, heptylene group, octylene group, 2-ethylhexylene group, nonylene group, decylene group, dimethyloctylene group, dodecylene group, cyclopentylene group, cyclohexylene group and the like.

  The polymer of the present invention has improved solubility in a solvent due to the presence of an alkyl group or an alkoxy group. In these polymers, it is important to improve the solubility in a solvent because the manufacturing tolerance of the wet film-forming process in the production of an organic EL element or an organic transistor element is increased. With improved solubility, for example, the choice of coating solvent, the temperature range during solution preparation, and the temperature range and pressure range during solvent drying can be expanded. In addition, a high-quality thin film with high purity and high uniformity is obtained.

    EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited by these examples unless it exceeds the gist.

[Example 1]
<Synthesis of Polymer 1>
Polymer 1 was synthesized by the following reaction.

In a 50 ml three-necked flask, 0.910 g (1.5 mmol) of the diboron ester, 1.237 g (1.5 mmol) of dibromo, 9.1 mg (0.075 mmol) of phenylboronic acid, Aliquat 336 as a phase transfer catalyst. (Aldrich) 12.5 mg (0.031 mmol) and tetrakistriphenylphosphinepalladium 10.0 mg (0.0087 mmol) were added, and after replacing with argon gas, 9 ml of toluene degassed with argon gas and 2M sodium carbonate After sequentially adding 3.5 ml of an aqueous solution and refluxing for 5 hours, as a stop reaction, first, 70 mg (0.57 mmol) of phenylboronic acid was added and refluxed for 2 hours, and then 150 mg (0.96 mmol) of bromobenzene was added and 2 Reflux for hours. Thereafter, the reaction solution was returned to room temperature, and then the organic layer was dropped into a mixed solvent of methanol / water and reprecipitated to obtain a crude polymer. Next, the obtained polymer was made into a chloroform solution, and 1 g of palladium scavenger silica gel (manufactured by Aldrich) was added thereto, followed by stirring at room temperature for 1 hour to remove residual palladium in the polymer. After the silica gel was filtered off, washing was repeated with ion-exchanged water until the conductivity of the washing liquid became equivalent to that of ion-exchanged water. After washing, the polymer was made into a tetrahydrofuran solution, and the polymer was purified by dropwise addition to methanol and reprecipitation.
The yield was 1.15 g, and the yield was 75%.
The number average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography) was 55400, and the weight average molecular weight was 130500.
Elemental analysis value (calculated value); C: 75.49% (75.54%), H: 8.75% (8.72%), S: 12.67% (12.60%)
The infrared absorption spectrum (NaCl cast film) is shown in FIG.

[Example 2]
<Synthesis of Polymer 2>
Polymer 2 was synthesized by the following reaction.

In a 50 ml three-necked flask, 0.699 g (1.5 mmol) of the above diboron ester, 1.237 g (1.5 mmol) of dibromo, 14.6 mg (0.12 mmol) of phenylboronic acid, Aliquat 336 as a phase transfer catalyst. (Aldrich) 12.5 mg (0.031 mmol) and tetrakistriphenylphosphinepalladium 10.0 mg (0.0087 mmol) were added, and after replacing with argon gas, 9 ml of toluene degassed with argon gas and 2M sodium carbonate After sequentially adding 3.5 ml of an aqueous solution and refluxing for 5 hours, as a stop reaction, first, 70 mg (0.57 mmol) of phenylboronic acid was added and refluxed for 2 hours, and then 150 mg (0.96 mmol) of bromobenzene was added and 2 Reflux for hours. Thereafter, the reaction solution was returned to room temperature, and then the organic layer was dropped into a mixed solvent of methanol / water and reprecipitated to obtain a crude polymer. Next, the obtained polymer was made into a chloroform solution, and 1 g of palladium scavenger silica gel (manufactured by Aldrich) was added thereto, followed by stirring at room temperature for 1 hour to remove residual palladium in the polymer. After the silica gel was filtered off, washing was repeated with ion-exchanged water until the conductivity of the washing liquid became equivalent to that of ion-exchanged water. After washing, the polymer was made into a tetrahydrofuran solution, and the polymer was purified by dropwise addition to methanol and reprecipitation.
The yield was 0.48 g, and the yield was 37%.
The number average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography) was 3600, and the weight average molecular weight was 5400.
Elemental analysis value (calculated value); C: 74.19% (73.92%), H: 7.60% (7.81%), S: 14.45% (14.62%)
The infrared absorption spectrum (NaCl cast film) is shown in FIG.

[Example 3]
<Synthesis of Polymer 3>
Polymer 3 was synthesized by the following reaction.

In a 50 ml three-necked flask, 0.798 g (1.45 mmol) of the above diboron ester, 1.237 g (1.5 mmol) of dibromo, 18.3 mg (0.15 mmol) of phenylboronic acid, Aliquat 336 as a phase transfer catalyst. (Aldrich) 12.5 mg (0.031 mmol) and tetrakistriphenylphosphinepalladium 10.5 mg (0.0091 mmol) were added, and after replacing with argon gas, 9 ml of toluene deaerated with argon gas and 2M sodium carbonate After sequentially adding 3.5 ml of an aqueous solution and refluxing for 4 hours, as a stop reaction, first, 70 mg (0.57 mmol) of phenylboronic acid was added and refluxed for 3 hours, and then 150 mg (0.96 mmol) of bromobenzene was added. Reflux for hours. Thereafter, the reaction solution was returned to room temperature, and then the organic layer was dropped into a mixed solvent of methanol / water and reprecipitated to obtain a crude polymer. Next, the obtained polymer was made into a chloroform solution, and 1 g of palladium scavenger silica gel (manufactured by Aldrich) was added thereto and stirred at room temperature for 1 hour to remove residual palladium in the crude polymer. After the silica gel was filtered off, washing was repeated with ion-exchanged water until the conductivity of the washing liquid became equivalent to that of ion-exchanged water. After washing, the polymer was made into a tetrahydrofuran solution, and the polymer was purified by dropwise addition to methanol and reprecipitation.
The yield was 1.18 g and the yield was 82%.
The number average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography) was 8000, and the weight average molecular weight was 16,200.
Elemental analysis value (calculated value); C: 75.08% (74.95%), H: 8.44% (8.39%), S: 13.16% (13.34%)
The infrared absorption spectrum (NaCl cast film) is shown in FIG.

[Example 4]
<Synthesis of Polymer 4>
Polymer 4 was synthesized by the following reaction.

In a 50 ml three-necked flask, 0.910 g (1.5 mmol) of the above diboron ester, 0.486 g (1.5 mmol) of dibromo, and 15.7 mg (0.039 mmol) of Aliquat 336 (manufactured by Aldrich) as a phase transfer catalyst. ), 10.2 mg (0.0088 mmol) of tetrakistriphenylphosphinepalladium was added, and after replacing with argon gas, 11 ml of toluene degassed with argon gas and 3.5 ml of 2M-sodium carbonate aqueous solution were added and refluxed for 3 hours. As a termination reaction, 80 mg (0.66 mmol) of 4-propoxyphenylboronic acid was first added and refluxed for 4 hours, and then 150 mg (0.96 mmol) of bromobenzene was added and refluxed for 4 hours. Thereafter, the reaction solution was returned to room temperature, and then the organic layer was dropped into a mixed solvent of methanol / water and reprecipitated to obtain a crude polymer. Next, the obtained polymer was made into a chloroform solution, and 1 g of palladium scavenger silica gel (manufactured by Aldrich) was added thereto and stirred at room temperature for 1 hour to remove residual palladium in the crude polymer. After the silica gel was filtered off, washing was repeated with ion-exchanged water until the conductivity of the washing liquid became equivalent to that of ion-exchanged water. After washing, the polymer was made into a tetrahydrofuran solution, and the polymer was purified by dropwise addition to methanol and reprecipitation.
The yield was 0.380 g, and the yield was 49%.
The number average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography) was 2500, and the weight average molecular weight was 3,200.
Elemental analysis value (calculated value); C: 74.65% (74.38%), H: 7.23% (7.02%), S: 12.55% (12.41%)
The infrared absorption spectrum (NaCl cast film) is shown in FIG.

[Example 5]
<Synthesis of Polymer 5>
Polymer 5 was synthesized by the following reaction.

In a 50 ml three-necked flask, 0.910 g (1.5 mmol) of the diboron ester, 0.609 g (1.5 mmol) of dibromo, and 12.5 mg (0.031 mmol) of Aliquat 336 (manufactured by Aldrich) as a phase transfer catalyst. ), 10.0 mg (0.0087 mmol) of tetrakistriphenylphosphine palladium was added, and after replacing with argon gas, 9 ml of toluene deaerated with argon gas and 3.5 ml of 2M sodium carbonate aqueous solution were sequentially added and refluxed for 3 hours. Then, as a termination reaction, first, 70 mg (0.57 mmol) of phenylboronic acid was added and refluxed for 2 hours, and then 150 mg (0.96 mmol) of bromobenzene was added and refluxed for 2 hours. Thereafter, the reaction solution was returned to room temperature, and then the organic layer was dropped into a mixed solvent of methanol / water and reprecipitated to obtain a crude polymer. Next, the obtained polymer was made into a chloroform solution, and 1 g of palladium scavenger silica gel (manufactured by Aldrich) was added thereto, followed by stirring at room temperature for 1 hour to remove residual palladium in the polymer. After the silica gel was filtered off, washing was repeated with ion-exchanged water until the conductivity of the washing liquid became equivalent to that of ion-exchanged water. After washing, the polymer was made into a tetrahydrofuran solution, and the polymer was purified by dropwise addition to methanol and reprecipitation.
The yield was 0.42 g, and the yield was 47%.
The number average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography) was 4100, and the weight average molecular weight was 5600.
Elemental analysis value (calculated value); C: 72.45% (72.20%), H: 6.31% (6.40%), S: 15.5.8% (16.06%)
The infrared absorption spectrum (NaCl cast film) is shown in FIG.

[Example 6]
<Synthesis of Polymer 6>
Polymer 6 was synthesized by the following reaction.

In a 50 ml three-necked flask, 0.699 g (1.5 mmol) of the above diboron ester, 0.615 g (1.5 mmol) of dibromo, 9.1 mg (0.075 mmol) of phenylboronic acid, Aliquat 336 as a phase transfer catalyst. (Aldrich) 13.4 mg (0.033 mmol) and tetrakistriphenylphosphinepalladium 10.0 mg (0.0087 mmol) were added, and after replacing with argon gas, 10 ml of toluene deaerated with argon gas and 2M sodium carbonate After sequentially adding 3.5 ml of an aqueous solution and refluxing for 3 hours, as a stop reaction, first, 80 mg (0.65 mmol) of phenylboronic acid was added and refluxed for 2 hours, and then 150 mg (0.96 mmol) of bromobenzene was added and 2 Reflux for hours. Thereafter, the reaction solution was returned to room temperature, and then the organic layer was dropped into a mixed solvent of methanol / water and reprecipitated to obtain a crude polymer. Next, the obtained polymer was made into a chloroform solution, and 1 g of palladium scavenger silica gel (manufactured by Aldrich) was added thereto, followed by stirring at room temperature for 1 hour to remove residual palladium in the polymer. After the silica gel was filtered off, washing was repeated with ion-exchanged water until the conductivity of the washing liquid became equivalent to that of ion-exchanged water. After washing, the polymer was made into a tetrahydrofuran solution, and the polymer was purified by dropwise addition to methanol and reprecipitation.
The yield was 0.40 g, and the yield was 58%.
The number average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography) was 3400, and the weight average molecular weight was 6200.
Elemental analysis value (calculated value); C: 78.10% (77.88%), H: 8.03% (8.28%), S: 6.75% (6.93%)
The infrared absorption spectrum (NaCl cast film) is shown in FIG.

[Application Example 1]
The surface of the p-doped silicon substrate acting as a gate was thermally oxidized to form an SiO ₂ insulating layer having a thickness of 200 nm, and then the oxide film was removed only on one side, and Al was evaporated on the removed side to form a gate electrode. Next, a 0.1 wt% chloroform solution of the polymer 1 obtained in Example 1 was cast on the SiO ₂ insulating layer and dried to prepare an organic semiconductor layer. Subsequently, 100 nm of Au serving as a source / drain electrode was deposited so that the channel length was 55 μm and the channel width was 2000 μm.
Moreover, the field effect mobility of the organic semiconductor was computed using the following formula | equation.
I _ds = μC _in W (V _g −V _th ) 2 / 2L
(Where C _in is the capacitance per unit area of the gate insulating film, W is the channel width, L is the channel length, V _g is the gate voltage, I _ds is the source drain current, μ is the mobility, and V _th is the channel. (This is the threshold voltage of the gate to start.)
The mobility of the manufactured TFT was 5.0 × 10 ⁻⁴ (cm ² / Vsec).
The on-off ratio (Vds = -20V, and _{I ds} in Vg = -40V, Vds = -20V, Vg = + 10~-40V ratio of minimum Ids observed within the) at 4.5 × 10 ³ The threshold voltage was −6.60V.

[Application 2]
The surface of the p-doped silicon substrate acting as a gate was thermally oxidized to form an SiO ₂ insulating layer having a thickness of 200 nm, and then the oxide film was removed only on one side, and Al was evaporated on the removed side to form a gate electrode. Next, an organic semiconductor layer was produced by casting and drying about 0.1 wt% chloroform solution of the polymer 3 obtained in Example 3 on the SiO ₂ insulating layer. Subsequently, 100 nm of Au serving as a source / drain electrode was deposited so that the channel length was 55 μm and the channel width was 2000 μm.
When the field effect mobility, the on / off ratio, and the threshold voltage were obtained in the same manner as in Application Example 1,
The mobility of the fabricated TFT was 2.5 × 10 ⁻⁴ (cm ² / Vsec), the on / off ratio was 6.0 × 10 ³ , and the threshold voltage was −7.03 V.

Infrared absorption spectrum of polymer 1 obtained in Example 1 Infrared absorption spectrum of polymer 2 obtained in Example 2 Infrared absorption spectrum of polymer 3 obtained in Example 3 Infrared absorption spectrum of polymer 4 obtained in Example 4 Infrared absorption spectrum of the polymer 5 obtained in Example 5 Infrared absorption spectrum of the polymer 6 obtained in Example 6

Claims (2)

The polymer containing the structural unit represented by the following general formula (I).

(Ar ₁ and Ar ₂ are a divalent group of a substituted or unsubstituted aromatic hydrocarbon group,
R ₁ is a substituted or unsubstituted alkylene group,
n is an integer of 1 or more,
R ₂ is a group selected from the group consisting of a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted alkylthio group;
x represents an integer from 0 to 2,
R ₂ when n is 1 and x is 2 may be the same or different,
When n is 2 or more, each R ₂ may be the same or different, and when n is 2 or more, each x may be the same or different. ) 2. The polymer having a repeating unit according to claim 1, wherein the polymer having the repeating unit represented by the general formula (I) is represented by the following general formula (II).

(R ₁ is a substituted or unsubstituted alkylene group,
n is an integer of 1 or more,
R ₂ , R ₃ and R ₄ are groups selected from the group consisting of substituted or unsubstituted alkyl groups, substituted or unsubstituted alkoxy groups, and substituted or unsubstituted alkylthio groups,
x represents an integer from 0 to 2,
R ₂ when n is 1 and x is 2 may be the same or different,
when n is 2 or more, each R ₂ may be the same as or different from each other;
When n is 2 or more, each x may be the same or different,
y and z each represents an integer of 0 to 4, and may be the same or different. )

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