JP2009001601A - Thiophene group-containing polymer and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thiophene group-containing polymer useful as a polymer material for a photoelectric conversion element having high hole transporting property and high durability, for a light emitting element having excellent emission property and high durability, and for an active layer of a thin film transistor, and a method for producing the polymer. <P>SOLUTION: The thiophene group-containing polymer has a constitutional unit represented by general formula (I), wherein Ar<SB>1</SB>-Ar<SB>4</SB>each independently represents a divalent group of a substituted or unsubstituted aromatic hydrocarbon or a substituted or unsubstituted aromatic heterocycle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polymer having a thiophene group in a side chain and a method for producing the same, and relates to a π-conjugated polymer useful as various organic electronics materials such as a photoelectric conversion element, a thin film transistor element, and a light emitting element.

Various functional elements such as a photoelectric conversion element, a thin film transistor element, and a light emitting element have been proposed by utilizing the light emission characteristics and charge transport characteristics of organic materials. The use of these organic materials is expected to provide devices that make maximum use of organic materials such as light weight, low cost, low manufacturing cost, and flexibility.
Among these functional elements, various materials such as low molecular weight materials and high molecular weight materials have been reported as hole transport materials for photoelectric conversion elements, particularly solar cells and electrophotographic photoreceptors. The former low molecular weight material is required to have higher efficiency, and the latter high molecular weight material is required to increase the printing speed and durability.

Further, various laminated structures of low molecular weight materials are adopted as materials for light emitting elements. It has been reported that the laminated structure of this low molecular weight material has been improved in efficiency and improved in durability by a controlled doping method. However, it has been reported that the state of the film changes over time in a low molecular weight aggregate, and there is a problem in the stability of the film.
On the other hand, in the polymer materials, conventionally, mainly PPV (poly-p-phenylenevinylene) series and poly-thiophene have been studied. However, it is difficult to raise the purity of these material systems, and there is a problem that the fluorescence quantum yield is essentially low. Therefore, the present condition is that the high performance light emitting element is not obtained. A polymer material is generally considered to have a stable glass state, and if a high fluorescence quantum efficiency can be imparted to the polymer material, an excellent light-emitting element can be constructed. For this reason, further improvements have been made in this area. For example, invention of the light emitting element using the polymeric material which contains an arylamine unit as a repeating unit can be mentioned (refer patent documents 1-4 and nonpatent literature 1).

In addition, it has been reported that various materials of low molecular weight and high molecular weight are used for the organic thin film transistor element. Examples of the low molecular weight material include pentacene, phthalocyanine, fullerene, anthradithiophene, thiophene oligomer, and bisdithienothiophene. Examples of the polymer material include polythiophene, polythienylene vinylene, and a polymer material containing an arylamine unit as a repeating unit (for example, Patent Document 5).
Patent Document 5 described above is an invention previously proposed by the present inventors. In this document, in a polymer material represented by a polymer material having an arylamine unit, the mobility, which is a characteristic value in a material for organic electronics, is remarkably improved. Considering application to organic electronics materials, especially organic FET devices, materials with higher mobility are desired.
In addition, it can be manufactured at low cost, has sufficient flexibility and strength, is lightweight, and can take advantage of the maximum characteristics of elements using organic materials that can be made large in area. It is necessary to have sex. In general, a π-conjugated polymer having a structure in which conjugation is extended has a rigid structure and therefore lacks solubility. There are many high molecular weight materials with poor solubility even in the above-mentioned conventionally known polymers, and the present situation is that various molecular design trials and errors have been made to avoid this.
US Pat. No. 5,777,070 Japanese Patent Laid-Open No. 10-310635 JP-A-8-157575 Japanese translation of PCT publication No. 2002-515078 JP 2005-240001 A Synth. Met. , 84, 269 (1997)

  The present invention has been made in view of the above problems of the prior art, and is a polymer for a photoelectric conversion element having both high hole transportability and high durability, and a light emitting element with excellent light emission characteristics and high durability. It is an object of the present invention to provide a polymer, a polymer useful as a polymer material for an active layer of a thin film transistor, and a method for producing the same.

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 arrived at the present invention.
That is, this invention is the following (1)-(6).
(1) A thiophene group polymer containing a structural unit represented by the following general formula (I).

(In the general formula (I), Ar _{1 to} Ar ₄ each independently represents a divalent group containing a substituted or unsubstituted aromatic hydrocarbon or a substituted or unsubstituted aromatic heterocyclic ring. R ¹ represents , A halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted alkylthio group, and x represents an integer of 1 to 3. R ² represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic hydrocarbon group.
(2) The thiophene group polymer as described in (1) above, wherein the structural unit represented by the general formula (I) is a structural unit represented by the following general formula (II).

(In the general formula (II), Ar ₁ , Ar ₂ , R ¹ , R ² and x have the same meaning as in the general formula (I), and R ³ and R ⁴ are each independently a halogen atom, 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, and y and z are each independently an integer of 1 or more and 4 or less And when y or z is 2 or more, each R ³ and R ⁴ may be independently the same or different.)
(3) The thiophene group polymer as described in (2) above, wherein the structural unit represented by the general formula (II) is a structural unit represented by the following general formula (III).

(In the general formula (III), R ⁵ is a group selected from the group consisting of a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted alkylthio group. , U represents an integer of 1 to 4, and when u is 2 or more, R ⁵ may be the same or different.
(4) The thiophene group polymer according to any one of (1) to (3), wherein at least one R ¹ group is bonded to the 5-position.
(5) A method for producing the polymer according to any one of (1) to (4) above, represented by a dialdehyde compound represented by the following general formula (IV) and the following general formula (V): A method for producing a thiophene-containing polymer comprising reacting a diphosphonic acid ester compound.

(In the general formula (IV), Ar _{2 to} Ar ₄ , R ¹ and x have the same meaning as in the general formula (I).)

(In the general formula (V), Ar ₁ and R ² have the same meaning as in the general formula (I), R ′ represents an alkyl group, and each R ′ may be the same or different.)
(6) In the dialdehyde compound represented by the general formula (IV), at least one R ¹ is bonded to the 5-position. The thiophene group polymer according to (5), Production method.

  The polymer of the present invention is a polymer material for a photoelectric conversion element having high hole transportability and excellent durability, as a polymer material for a light emitting element having excellent light emission characteristics and durability, It is particularly useful as a polymer material for an active layer of a thin film transistor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The thiophene group polymer of the present invention has a structural unit represented by the following general formula (I).

In the general formula (I), Ar _{1 to} Ar ₄ each independently represent a substituted or unsubstituted aromatic hydrocarbon or a divalent group of a substituted or unsubstituted aromatic heterocyclic ring. R ¹ is a group selected from the group consisting of a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted alkylthio group, and x is an integer of 1 or more and 3 or less Represents. R ² represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic hydrocarbon group.

The divalent group containing a substituted or unsubstituted aromatic hydrocarbon in Ar _{1 to} Ar ₄ in the general formula (I) is any of a monocyclic group and a polycyclic group (a condensed polycyclic group or a non-condensed polycyclic group). However, examples of the aromatic hydrocarbon divalent group include the following. For example, bivalent groups such as phenylene group, naphthylene group, anthracenyl group, pyrenylene group, fluorenylene group, azulylene group, anthrylene group, triphenylenylene group, chrysenylene group, biphenylene group, terphenylene group, diphenyl ether group, polyethylene diphenyl ether group, diphenyl Bivalent groups of monocyclic hydrocarbon compounds such as thioether groups and diphenylsulfone groups, or polyphenylene groups having multiple monocycles such as biphenylene groups and terphenylene groups, diphenylalkyl groups, diphenylalkene groups, diphenylalkyne groups, triphenyl groups Methyl group, diphenylstyryl group, distyrylphenyl group, distyrylbenzyl group, 1,1-diphenylcycloalkyl group, polyphenylalkyl group, polyphenylalkene group, polyphenyl Diradical non condensed polycyclic hydrocarbon compounds such as Niruarukin group or divalent group ring assembly hydrocarbon compounds such as 9,9-diphenyl fluorene and the like.

  The divalent group containing an aromatic heterocycle preferably has 18 or less carbon atoms forming the ring, for example, a pentanylene group, an indenylene group, a naphthylene group, an azlenylene group, a heptanylene group, an as-indacenylene group, s -Indasenylene group, fluorenylene group, acenaphthynylene group, preadenylene group, acenaphthenylene group, phenalenylene group, phenanthrylene group, anthrylene group, fluoranthenylene group, acephenanthryleneylene group, aceanthryllenylene group, triphenylenylene group, pyrenylene group Divalent groups such as thiophene, benzothiophene, dithienylbenzene, furan, benzofuran, carbazole, oxadiazole group (including diphenyloxadiazole group), and the like.

When the above-described aromatic hydrocarbon or aromatic divalent divalent group has a substituent, examples of the substituent include the following substituents.
(1) Halogen atom (F, Cl, Br, I, etc.), trifluoromethyl group, cyano group, nitro group, sulfide (—SH), sulfone group, etc.
(2) C1-C25 unsubstituted or substituted alkyl group, alkoxy group (alkyl groups are methyl, ethyl, propyl (n-propyl, iso-propyl)), butyl (n-butyl) Group, iso-butyl group, tert-butyl group), pentyl group (n-pentyl group, iso-pentyl group, tert-pentyl group, etc.), hexyl group, heptyl group, octyl group, etc. And an alicyclic alkyl group such as an alkyl group, cyclopentyl group, cyclohexyl group, etc. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, and a t-butoxy group. , N-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, trifluoromethoxy group, etc. 5 aliphatic alkoxy group, an aromatic alkoxy group such as a benzyl group of 1 to 25 carbon atoms.).
(3) Aryloxy group (an aryloxy group having a phenyl group or a naphthyl group as the aryl group. Examples thereof include an unsubstituted or substituted alkyl group having 1 to 25 carbon atoms, an unsubstituted or substituted alkyl group having 1 to 25 carbon atoms, or A substituted alkoxy group or a halogen atom may be contained as a substituent, specifically, a phenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, 4-methylphenoxy group, 4-methoxyphenoxy group, 4-chlorophenoxy group, 6-methyl-2-naphthyloxy group, benzyloxy group, etc.).
(4) Alkylthio group or arylthio group (specifically, methylthio group, ethylthio group, phenylthio group, p-methylphenylthio group, etc.).
(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, etc.).
(6) Acyl group (Specific examples of the acyl group include acetyl group, propionyl group, butyryl group, malonyl group, and benzoyl group).
Moreover, said aromatic hydrocarbon group and aromatic heterocyclic group may have a substituent shown in above-mentioned (1)-(6).

In the general formula (I), R ¹ is a group selected from the group consisting of a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted alkylthio group. , X represents an integer of 1 or more and 3 or less. Examples of such a case where R ¹ is a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkoxy group have been explained in the above-mentioned section of the substituent such as Ar ₁ , Omitted.

In the general formula (I), the monovalent group of R ² is a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted aromatic hydrocarbon group. Examples of the substituted or unsubstituted alkyl group include the same substituents as those described in the section of the substituent for R ¹ .
Examples of the substituted or unsubstituted aromatic hydrocarbon group include monovalent groups such as 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. Groups, diphenyl ether groups, polyethylene diphenyl ether groups, monovalent hydrocarbon compounds such as diphenyl thioether groups and diphenyl sulfone groups, or polyphenyl groups having a plurality of monocycles such as biphenyl groups and terphenyl groups, diphenylalkyl Group, diphenylalkene group, diphenylalkyne group, triphenylmethyl group, distyrylphenyl group, distyrylbenzyl group, 1,1-diphenylcycloalkyl group, polyphenylalkyl group, polyphenylalkene group, polyphenylalkyne Monovalent groups of non-condensed polycyclic hydrocarbon compounds, or the monovalent radical of a ring assembly hydrocarbons compounds such as 9,9-diphenyl fluorene like equal.

  Further, the monovalent group of the aromatic hydrocarbon preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a heptanyl group, an as-indacenyl group, an s-indacenyl group, a fluorenyl group. Acenaphthynyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylenyl group, pyrenyl group, chrysenyl group, and naphthacenyl group, And monovalent groups such as thiophene, benzothiophene, dithienylbenzene, furan, benzofuran, and carbazole.

In the polymer having the structural unit represented by the general formula (I), Ar ₃ is preferably —φ (R ³ ) _y —, and Ar ₄ is represented by —φ (R ⁴ ) _z —. It is preferable that it is a divalent phenyl group. When such a structural unit is represented directly, it becomes a structural unit represented by the following (II).
Where φ is a divalent phenylene group having a substituent, and in Ar _{3 to} Ar ₄ , R ³ and R ⁴ are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group A group selected from the group consisting of a group and a substituted or unsubstituted alkylthio group, y and z each independently represent an integer of 1 or more and 4 or less, and when y or z is 2 or more, each group R ³ And R ⁴ may be the same or different.

Since these substituents Ar ₁ , Ar ₂ and R ^{1 to} R ⁴ are the same as those described above, such as an alkyl group, an alkoxy group, and an alkylthio group, the description thereof is omitted. Further, since the substituents that may be contained in these are the same as the above-described substituents, the description thereof is omitted.

Particularly in the structural unit represented by the general formula (I) or (II), the divalent group of Ar ₂ is a group represented by the following general formula (2) (a phenylene group which may have a substituent: -φ ^(R _{5) u -)} a is preferably a a compound (III).

In the general formula (2), R ⁵ is a group selected from the group consisting of a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted alkylthio group, u represents an integer of 1 or more and 4 or less, and when u is 2 or more, 2 or more of R ⁵ may be the same or different. Regarding R ^{5, the} description of the group such as a halogen atom, an alkyl group, an alkoxy group, and an alkylthio group is omitted because it is the same group as described above. Further, since the substituents that may be contained in these are the same as the above-described substituents, the description thereof is omitted.

The polymer having the structural unit represented by (I), (II) and the divalent group of Ar _{2 in} the present invention represented by the general formula (2), specifically, (III) is aromatic as described above. It is more preferable to have a substituent on the ring and to have a substituent such as an alkyl group, an alkoxy group or an alkylthio group from the viewpoint of improving the solubility in an organic solvent. If the number of carbons of these substituents increases, the solubility is further improved, but on the other hand, characteristics such as charge transportability generally decrease, so that desired characteristics can be obtained within a range where the solubility is not impaired. It is preferable to select a substituent. Examples of suitable substituents in that case include alkyl groups having 1 to 25 carbon atoms, alkoxy groups, and alkylthio groups. More preferable examples include an alkyl group having 2 to 18 carbon atoms, an alkoxy group, and an alkylthio group. As these substituents, a plurality of the same groups may be introduced, or a plurality of different groups may be introduced. In addition, these alkyl groups, alkoxy groups and alkylthio groups are further halogen atoms, cyano groups, phenyl groups, hydroxyl groups, carboxyl groups, linear, branched or cyclic alkyl groups or alkoxy groups having 1 to 12 carbon atoms, alkoxythio groups, alkylthio groups. A phenyl group substituted with a group may be contained.

The polymer of the present invention is a structural unit in which at least one R ¹ group is bonded to the 5-position in the polymer having a polymer unit represented by the general formula (I), (II) or (III). It is preferable to have.
In particular, in the polymer having a polymer unit represented by the general formula (I), (II) or (III), it is preferable that at least one R ¹ group is bonded to the 5-position.

  Since the polymer of the present invention has an alkyl group, an alkoxy group, or an alkylthio group, the solubility in a solvent is improved. It is important to improve the solubility of these materials because the tolerance is increased in manufacturing including a wet film forming process when manufacturing a photoelectric conversion element, a thin film transistor element, and a light emitting element. For example, the choice of the coating solvent used in the coating liquid used in wet film formation is expanded, the temperature range during solution preparation is expanded, and the temperature and pressure range during drying after coating the coating liquid Will expand. By increasing these processability, high-quality thin films with high purity and high uniformity can be obtained.

Next, the manufacturing method of the polymer which has a structural unit represented by general formula (I) of this invention is demonstrated.
The polymer production method of the present invention uses a Wittig-Horner reaction using an aldehyde and a phosphonate, a Wittig reaction using an aldehyde and a phosphonium salt, a Heck reaction using a vinyl substituent and a halide, or an amine and a halide. It can be produced using the Ullmann reaction. In particular, the Wittig-Horner reaction and the Wittig reaction are effective because of the simplicity of the reaction operation.

The polymer production method of the present invention can utilize, for example, the Wittig-Horner reaction. A method for producing the polymer of the present invention using such Wittig-Horner reaction will be described below.
The polymer in the present invention generally has a phosphonic acid ester compound and an aldehyde compound (diphosphonic acid ester compound and dialdehyde compound) substantially stoichiometrically as shown in Scheme 1 described below. And the polymerization reaction can be allowed to proceed in the presence of at least twice the molar amount of the base. A random copolymer can also be obtained by adding a plurality of types of phosphonic acid ester compounds or aldehyde compounds to the reaction system. By using such a technique, various kinds of polymers can be obtained as appropriate. It is also possible to adjust the characteristics.

  The dialdehyde compound represented by the general formula (IV) ′ used in the present invention is an example of the following formula (IV), and is a diphosphonate compound represented by the general formula (V) ′. Is an example of the following formula (V).

In the general formula (IV), Ar _{2 to} Ar ₄ , R ¹ and x have the same meaning as in the general formula (I).
In the general formula (V), Ar ₁ and R ² have the same meaning as in the general formula (I), R ′ represents an alkyl group having 1 to 50 carbon atoms, and each R ′ is the same or different. Also good.
Specific examples of the diphosphonate compound represented by the general formula (V) include compounds represented by the following formulas (V-1) to (V-13).

The base used in the reaction shown in the above scheme 1 is not particularly limited as long as a phosphonate carbanion (= C ⁻ —PO (OR) ₂ ) is formed. Examples of the base include metal alcoside, metal hydride, organic Examples of the lithium compound include potassium t-butoxide, sodium t-butoxide, lithium t-butoxide, potassium 2-methyl-2-butoxide, sodium 2-methyl-2-butoxide, sodium methoxide, sodium ethoxide, and potassium. Ethoxide, potassium methoxide, sodium hydride, potassium hydride, methyl lithium, ethyl lithium, propyl lithium, n-butyl lithium, s-butyl lithium, t-butyl lithium, phenyl lithium, lithium naphthylide, lithium amide, lithium Diisopropylamide It can be mentioned.

  The amount of base used in the reaction is usually used in the same amount relative to the polymerization active point of the diphosphonic acid ester compound, but an excessive amount of base may be used.

  The above-described base may be added to the reaction system in a solid state or a suspended solution state. In order to improve the homogeneity of the resulting polymer, it is particularly preferable to add it as a homogeneous solution. As a solvent used as a homogeneous solution, a solvent that forms a stable solution with a base to be used is selected. For example, a base having a high solubility is selected as such a base, and this base is preferably one that does not impair the solubility of the high molecular weight compound produced in the reaction system in the reaction solvent (for example, less effective for salting out). Further, as the above-mentioned solvent, it is preferable to select a solvent in which the high molecular weight compound to be generated dissolves satisfactorily, and generally known alcohol-based, ether-based, Examples thereof include solvents arbitrarily selected from amine-based and hydrocarbon-based solvents.

  Examples of a combination of a base and a solvent for uniformly dissolving the base include, for example, a methanol solution of sodium methoxide, an ethanol solution of sodium ethoxide, a 2-propanol solution of potassium t-butoxide, and 2-methyl-2-methyl ester of potassium t-butoxide. Propanol solution, potassium t-butoxide in tetrahydrofuran, potassium t-butoxide in dioxane, n-butyllithium in hexane, methyllithium in ether, lithium t-butoxide in tetrahydrofuran (THF), lithium diisopropylamide in cyclohexane In addition, a toluene solution of potassium bistrimethylsilylamide, and the like, and those various combinations of base-solvents can be selected from commercially available products. From the viewpoint of mild reaction conditions and ease of handling, metal alkoxide and alcohol base solution, ether type, THF type and the like are preferable. Solubility of polymer to be produced, ease of handling, reaction efficiency From the viewpoints of solubility, solubility of the polymer to be produced, etc., a metal t-butoxide ether type, THF type, more preferably potassium t-butoxide solution in tetrahydrofuran (THF) is preferable.

The polymerization reaction may be carried out by adding the base solution to the solution (base method) of the solution of the phosphonate ester compound and the aldehyde compound (diphosphonate ester compound and dialdehyde compound) and the base solution. The solution of the phosphonate ester compound and the aldehyde compound may be added to the base solution, and may be added simultaneously to the reaction system, and the order of addition is not limited.
What is necessary is just to set suitably the polymerization time required for a polymerization reaction according to the reactivity of the monomer used, or the molecular weight of a polymer, for example, 0.2 hours-30 hours are preferable.

  The reaction temperature at the time of the polymerization reaction need not be particularly controlled, and the polymerization reaction proceeds well at room temperature (for example, 0 to 30 ° C.). Heating can be performed to increase the reaction efficiency, or cooling can be performed so as to react under milder conditions.

  In the above polymerization reaction, in order to adjust the molecular weight, a molecular weight regulator or a blocking agent for blocking or modifying the end of the polymer as a terminal modifying group is used at the start of the reaction, during the reaction or after the reaction. It is also possible to add. Accordingly, the π-conjugated polymer of the present invention may have a substituent based on a terminator bonded to one end or both ends.

  The preferred molecular weight of the polymer of the present invention is 1000 to 1,000,000, more preferably 2000 to 500,000 in terms of number average molecular weight (polystyrene conversion). When the molecular weight is less than 1000, the film formability such as the generation of cracks is deteriorated and the practicality becomes poor. On the other hand, if the molecular weight is larger than 1,000,000, the solubility in an organic solvent is deteriorated, the viscosity of the solution becomes high, and the processing characteristics such as coating become difficult, which is a practical problem. .

  In order to improve mechanical properties, a small amount of a branching agent can be added during polymerization. Examples of the branching agent used include compounds having three or more polymerization reaction active groups (which may be the same or different). These branching agents may be used alone or in combination.

  The polymer obtained as described above is used after removing the base, unreacted monomer, terminal terminator used in the polymerization, and impurities such as inorganic salts generated during the polymerization. For these purification operations, conventionally known purification methods such as decantation, reprecipitation, column chromatography, adsorption, extraction including Soxhlet extraction, ultrafiltration, dialysis and the like can be used.

  The polymer of the present invention obtained by the production method as described above is cracked by a known film formation method such as a spin coating method, a casting method, a dip method, an ink jet method, a doctor blade method, a screen printing method, or a dispensing method. Therefore, it is possible to produce a good thin film excellent in strength, toughness, durability and the like. The obtained thin film can be used suitably as a material for various functional elements such as a photoelectric conversion element, a thin film transistor element, and a light emitting element.

  The present invention will be described more specifically with reference to the following examples.

[Example 1]
In a 50 ml flask substituted with nitrogen gas, 0.662 g (1.417 mmol) of the dialdehyde compound represented by the above formula (IV-1) and 0.880 g of the diphosphonate compound represented by the above (V-5) ( 1.417 mmol) was dissolved in 20 ml of dehydrated tetrahydrofuran, and 4.2 ml of a 1.0 moldm ^-3 tetrahydrofuran solution of potassium t-butoxide was gradually added dropwise at room temperature. After dropping, the mixture was stirred at room temperature for 4.5 hours, then 23 mg of benzaldehyde was added and stirred for 1.5 hours, and then 45 mg of diethyl benzylphosphonate was added and stirred for 1.5 hours, and then neutralized with acetic acid. The neutralized content was dropped into water to obtain a crude polymer. This was purified by reprecipitation with tetrahydrofuran / methanol and then tetrahydrofuran / acetone, then dissolved in methylene chloride, and the washing was repeated with ion-exchanged water until the conductivity of the washing liquid became equivalent to that of ion-exchanged water. . After washing, it was dropped into methanol to obtain 0.33 g of the polymer-1 of the present invention represented by the following orange formula.

The elemental analysis value (%) of this polymer-1 is as follows.
However, it represents as an actual measurement value (calculated value).
C: 81.03 (81.28) H: 8.09 (7.93) N: 1.99 (1.93) S: 4.27 (4.43)
Moreover, the number average molecular weight of polystyrene conversion measured by GPC (gel permeation chromatograph) of this polymer-1 was 18,900, and the weight average molecular weight was 69,000.
The infrared absorption spectrum (measured with a NaCl cast film) of this polymer-1 is shown in FIG.

[Example 2]
In a 50 ml flask substituted with nitrogen gas, 0.862 g (1.843 mmol) of the dialdehyde compound represented by the above formula (IV-1) and 1.170 g of the diphosphonate compound represented by (V-9) described above. (1.843 mmol) was dissolved in 20 ml of dehydrated tetrahydrofuran, and 5.6 ml of a 1.0 mol · dm ⁻³ tetrahydrofuran solution of potassium t-butoxide was gradually added dropwise at room temperature. After dropping, the mixture was stirred at room temperature for 4.5 hours, 30 mg of benzaldehyde was added and stirred for 1.5 hours, and then 59 mg of diethyl benzylphosphonate was added and stirred for 1.5 hours, and then neutralized with acetic acid. The neutralized content was dropped into water to obtain a crude polymer. The crude polymer is purified by reprecipitation with tetrahydrofuran / methanol and then tetrahydrofuran / acetone, then dissolved in methylene chloride, and repeatedly washed with ion-exchanged water until the conductivity of the washing liquid is equivalent to ion-exchanged water. It was. After washing, it was dropped into methanol to obtain 0.91 g of polymer-2 of the present invention represented by the following formula of yellow.

Elemental analysis values of the obtained polymer-2 were as follows.
Elemental analysis value (%) Actual measurement value (calculated value)
C: 86.27 (86.20) H: 7.85 (8.00) N: 1.73 (1.76) S: 4.01 (4.04)
The number average molecular weight in terms of polystyrene measured by GPC of polymer-2 was 14,500, and the weight average molecular weight was 52,900.
The infrared absorption spectrum (NaCl cast film) of Polymer-2 is shown in FIG.

Example 3
In a 50 ml flask substituted with nitrogen gas, 0.766 g (1.637 mmol) of the dialdehyde compound represented by the above formula (IV-1) and 0.767 g of the diphosphonate compound represented by (V-13) described above. (1.637 mmol) was dissolved in 20 ml of dehydrated tetrahydrofuran, and 5.0 ml of a 1.0 mol · dm ⁻³ (1.0 M) tetrahydrofuran solution of potassium t-butoxide was gradually added dropwise at room temperature. After dropping, the mixture was stirred at room temperature for 3 hours, and then 27 mg of benzaldehyde was added and stirred for 1.5 hours, and then 52 mg of diethyl benzylphosphonate was added and stirred for 1.5 hours, and then neutralized with acetic acid. The neutralized content was dropped into water to obtain a crude polymer. This was treated with a silica gel column as a chloroform solution, and this polymer solution was washed with ion-exchanged water until the conductivity of the washing liquid became equivalent to that of ion-exchanged water. After washing, the washed product was dropped into methanol to obtain 0.35 g of polymer-3 of the present invention represented by the following orange formula.

Elemental analysis values of the obtained polymer-3 were as follows.
Elemental analysis value (%) Actual measurement value (calculated value)
C: 80.02 (80.34) H: 6.98 (7.22) N: 2.12 (2.23) S: 100.05 (10.21)
The number average molecular weight in terms of polystyrene measured by GPC of polymer-3 was 2,800, and the weight average molecular weight was 4,800.
Infrared absorption spectrum (NaCl cast film) of polymer-3 is shown in FIG.

[Application Example 1]
On a PET (polyethylene terephthalate) substrate on which an Al electrode was deposited, a 20 wt% tetrahydrofuran solution of the polymer-1 obtained in Example 1 was blade-coated to form a thin film having a thickness of 16.2 μm. A gold electrode was further deposited on the thin semiconductor film to produce a sandwich cell. Using this cell, the carrier mobility of the organic semiconductor material was measured by a time-of-flight method (TOF method). As a result, it was found that the electric field strength was 2.46E + 5 V / cm (2.46 × 10 ⁵ V / cm). A high carrier mobility of 22E-3 cm ² V ⁻¹ s ⁻¹ (2.22 × 10 ⁻³ cm ² V ⁻¹ s ⁻¹ ) was observed.

[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 about 1.0 wt% tetrahydrofuran solution of the polymer 1 obtained in Example 1 was spin-coated on the SiO ₂ insulating layer and dried to prepare an organic semiconductor layer. Subsequently, an Au film of source / drain electrodes was deposited so as to have a channel length of 30 μm and a channel width of 10 mm.

Moreover, the field effect mobility of the organic semiconductor was computed using the following formula | equation.
Ids = μCinW (Vg−Vth) ² / 2L
In the above equation, Cin is a capacitance per unit area of the gate insulating film, W is a channel width, L is a channel length, Vg is a gate voltage, Ids is a source-drain current, μ Is the mobility, and Vth is the threshold voltage of the gate where the channel begins to form.
When the mobility μ was determined using the above equation, the mobility of the fabricated TFT was 6.4 × 10 ⁻⁵ (cm ² / Vsec).
The ON / OFF ratio (ratio between Ids at Vds = −20V and Vg = −40V and minimum Ids observed within the range of Vds = −20V and Vg = + 20 to −40V) is 1.4 × 10. ⁴ and the threshold voltage was -14.00V.

[Application Example 3]
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 about 1.0 wt% tetrahydrofuran solution of the polymer 2 obtained in Example 2 was spin-coated on the SiO ₂ insulating layer and dried to prepare an organic semiconductor layer. Subsequently, an Au film of source / drain electrodes was deposited so as to have a channel length of 30 μm and a channel width of 10 mm.

The field effect mobility, the on / off ratio, and the threshold voltage were determined in the same manner as in Application Example 2. As a result, the mobility of the fabricated TFT was 7.6 × 10 ⁻⁵ (cm ² / Vsec), and the on / off The ratio was 1.1 × 10 ⁵ and the threshold voltage was −8.70V.

[Application Example 4]
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 about 1.0 wt% tetrahydrofuran solution of the polymer 3 obtained in Example 3 was spin-coated on the SiO ₂ insulating layer and dried to prepare an organic semiconductor layer. Subsequently, an Au film of source / drain electrodes was deposited so as to have a channel length of 30 μm and a channel width of 10 mm.

The field effect mobility, on / off ratio, and threshold voltage were determined in the same manner as in Application Example 2. As a result, the mobility of the fabricated TFT was 1.7 × 10 ⁻⁵ (cm ² / Vsec), and the on / off state was The ratio was 1.9 × 10 ⁵ and the threshold voltage was −1.43V.

  The polymer of the present invention is a polymer material for a photoelectric conversion element having high hole transportability and excellent durability, as a polymer material for a light emitting element having excellent light emission characteristics and durability, Further, it is particularly useful as a polymer material for an active layer of a thin film transistor.

It is an infrared absorption spectrum (NaCl cast film) of the polymer-1 obtained in Example 1, the horizontal axis represents wave number (cm ⁻¹ ), and the vertical axis represents transmittance (% T: transmittance%). . It is an infrared absorption spectrum (NaCl cast film) of the polymer-2 obtained in Example 2, the horizontal axis represents the wave number (cm ⁻¹ ), and the vertical axis represents the transmittance (% T: transmittance%). . It is an infrared absorption spectrum (NaCl cast film) of the polymer-3 obtained in Example 3, the horizontal axis represents the wave number (cm ⁻¹ ), and the vertical axis represents the transmittance (% T: transmittance%). .

Claims (6)

The thiophene group polymer which has a structural unit represented by the following general formula (I).

(In the general formula (I), Ar _{1 to} Ar ₄ each independently represents a divalent group containing a substituted or unsubstituted aromatic hydrocarbon or a substituted or unsubstituted aromatic heterocyclic ring. R ¹ represents , A halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted alkylthio group, and x represents an integer of 1 to 3. R ² represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic hydrocarbon group. The thiophene group polymer according to claim 1, wherein the structural unit represented by the general formula (I) is a structural unit represented by the following general formula (II).

(In the general formula (II), Ar ₁ , Ar ₂ , R ¹ , R ² and x have the same meaning as in the general formula (I), and R ³ and R ⁴ are each independently a halogen atom, 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, and y and z are each independently an integer of 1 or more and 4 or less And when y or z is 2 or more, each R ³ and R ⁴ may be independently the same or different.) The thiophene group polymer according to claim 2, wherein the structural unit represented by the general formula (II) is a structural unit represented by the following general formula (III).

(In the general formula (III), R ⁵ is a group selected from the group consisting of a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted alkylthio group. , U represents an integer of 1 to 4, and when u is 2 or more, the groups R ⁵ may be the same or different. The thiophene group polymer according to any one of claims 1 to 3, wherein at least one of the R ¹ groups is bonded to the 5-position. It is a manufacturing method of the thiophene group polymer in any one of Claims 1-4, Comprising: The dialdehyde compound represented by the following general formula (IV), and the diphosphonic acid ester represented by the following general formula (V) A method for producing a thiophene group polymer comprising reacting a compound.

(In the general formula (IV), Ar _{2 to} Ar ₄ , R ¹ and x have the same meaning as in the general formula (I).)

(In the general formula (V), Ar ₁ and R ² have the same meaning as in the general formula (I), R ′ represents an alkyl group, and each R ′ may be the same or different.) 6. The method for producing a thiophene-containing polymer according to claim 5, wherein in the dialdehyde compound represented by the general formula (IV), at least one R ¹ is bonded to the 5-position.

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