JP2003238773A - Conductive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a conductive composition which uses a polythiophene as a main constituent and can be manufactured simply and inexpensively. <P>SOLUTION: Chloroform solutions of polythiophenes (1)-(7), each of which is obtained by polymerization of the polythiophene introduced with one or two alkoxy groups such as methoxy group in the thiophene ring or a thiophene derivative having an alkyl-substituted cyclic ether structure, and an acetonitrile solution of Ag<SP>+</SP>(CF<SB>3</SB>SO<SB>3</SB><SP>-</SP>) are mixed so as for the final composition ratio of the monomer unit of the polythiophene/Ag<SP>+</SP>(CF<SB>3</SB>SO<SB>3</SB><SP>-</SP>) to be 1:1 (molar ratio) to prepare mixed solutions. The mixed solution is applied on a substrate, and then, chloroform and acetonitrile as the solvents, are evaporated to form a film from the mixtures of the polythiophenes (1)-(7) and Ag<SP>+</SP>(CF<SB>3</SB>SO<SB>3</SB><SP>-</SP>) which are conductive compositions. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a conductive composition, and more particularly to a conductive composition containing polythiophene as a constituent component.

[0002]

2. Description of the Related Art In recent years, polythiophene has been attracting attention as a functional polymer material, and many polymer-oriented materials such as polymer semiconductors, polymer conductors, electrochromic materials, electroluminescent materials, and nonlinear optical materials are used. Research cases have been reported.

In order to obtain a conductive polythiophene by a conventional method, it was necessary to electrochemically or chemically coexist (doping) a polythiophene with an electron accepting or electron donating chemical substance. For example, in the case of polythiophene which is soluble in an organic solvent, it is allowed to coexist with iodine molecules in a solution, and the solution is used to form a conductive film.
Or exposing the polythiophene film to iodine vapor,
Alternatively, conductivity was imparted by immersing in an iodine solution. In addition, a polythiophene film is formed on the surface of the electrode and is electrochemically redox-reduced to introduce the counterion of the supporting electrolyte into the film to impart conductivity.

[0004]

As described above, in order to realize a conductive polythiophene, a neutral chemical substance showing an electron accepting or electron donating property or a supporting electrolyte for electrochemical redox reaction is used. I needed it.

Further, a dispersion liquid in which polythiophene having enhanced conductivity is dispersed in water has also been developed, and such a dispersion liquid is applied to a substrate and water as a dispersion medium is evaporated to give a conductive polythiophene. Film can be formed, in which case the polythiophene content of the dispersion is 1
%, It is necessary to evaporate a large amount of water to form a thin film, and irregularities are recognized on the surface of the formed thin film, which may be a problem depending on the type of application.

As described above, in constructing an electronic functional device using a conductive polythiophene, there are major problems in terms of control of conductivity, conductive carrier concentration and mobility, convenience of film formation, and reproducibility. It was

An object of the present invention is to solve the above problems and to provide a conductive composition which can be produced simply and inexpensively by using polythiophene as a constituent component.

[0008]

In order to achieve the above object, the present invention provides a polythiophene represented by the following general formula 1 or general formula 2 and a metal salt or a protic acid as described in claim 1. And a conductive composition.

[0009]

[Chemical 2] Here, at least one of R ₁ and R ₂ is an alkoxy group, one of R ₁ and R ₂ may be hydrogen, and at least one of R ₃ and R ₄ is It is an alkyl group, and one of R ₃ and R ₄ may be hydrogen, and n is an integer of 10 or more and 100000 or less.

Further, according to the present invention, as described in claim 2, in the conductive composition according to claim 1, the cation component of the metal salt or protonic acid is Li ⁺ , Na ⁺ ,
K ⁺ , Fe ²⁺ , Fe ³⁺ , Cu ⁺ , Cu ²⁺ , A
g ⁺ , Zn ²⁺ , Eu ³⁺ or H ⁺ , and the anion component is ClO ₄ ⁻ , BF ₄ ⁻ , B (phenyl) ₄ ⁻ , B
_{(Pentafluorophenyl) 4} ^-, B (3,5-bis (trifluoromethyl) _{phenyl) 4} ^-, B (p-chlorophenyl)
₄ ^-, B (p- _{^{fluorophenyl) 4 -, CF 3 SO 3}} -
Alternatively, the electroconductive composition is characterized by being a camphorsulfonate ion.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive composition according to the present invention is characterized in that the conductive composition is a polythiophene obtained by polymerizing thiophene having at least one alkoxy group or thiophene having an alkyl-substituted cyclic ether structure. It is to be obtained only by mixing a metal salt or a protic acid, or by bringing a solution of these metal salt or a protic acid into contact with the polythiophene film.

The embodiments of the present invention will be described in detail below.

First, a synthetic example of substituted polythiophene will be shown.

An ether exchange reaction of an alkoxy-substituted thiophene (including the above-mentioned thiophene having an alkyl-substituted cyclic ether structure) in toluene with sodium hydrogen sulfate as a catalyst (see, for example, JP-A-2001-261796,
Fujiki, Nakajima, Kou, Zhang, Motonaga, see "Alkoxypolythiophene and alkoxythiophene").

This alkoxy-substituted thiophene is converted to ferric chloride oxidation method or alkoxy-substituted thiophene 2,5-
The dibromo compound was polymerized by an oxidative coupling reaction of Ni (0) bis (cyclooctadiene) to synthesize an alkoxy-substituted polythiophene. The polymers thus obtained were all alkoxy-substituted polythiophenes soluble in organic solvents. Table 1 shows the structural formula, molecular weight and other identification results of this alkoxy-substituted polythiophene.

[0016]

[Table 1] In Table 1, in the structural formula, C ₈ H ₁₇ -2 and 2-C ₈ H
₁₇ is an alkyl _{group: CH 3 (CH 2) 5} CH (CH 3) - and _represents, C _{8 H 17} -n and _{n-C 8 H 17} alkyl radical: C
H ₃ (CH _{2) 7} - _represents, C _{9 H 19} -n and _n-C 9 H
₁₉ represents an alkyl group: CH ₃ (CH ₂ ) ₈ —, and in the description of the polymerization method, “Ni (0) coupling” is 2,5
Represents a method of polymerizing a dibromo compound by an oxidative coupling reaction of Ni (0) bis (cyclooctadiene),
"FeCl ₃ Oxidation" converts thiophene into ferric chloride (F
eCl ₃ ) to oxidize and polymerize
_w represents a weight average molecular weight, and M _n represents a number average molecular weight.

In Table 1, all of the above alkyl groups and Me (methyl groups) are bonded to oxygen groups (--O--) to form alkoxy groups except for the case of polythiophene # 5. These alkoxy groups correspond to R ₁ or R ₂ in the above general formula 1. However, in the case of polythiophenes of Nos. 1, 2, and 3, R ₁ is hydrogen. Further, in the case of polythiophene of No. 5, R in the above general formula 2 is
₃ is hydrogen and R ₄ is an alkyl group: CH ₃ (CH ₂ ) ₇
-It is.

[0018]

The embodiments of the present invention will be described in detail below with reference to examples.

Example 1 Polythiophene shown in Table 1
Chloroform solution of Ag and one of the metal salts, Ag⁺(CF
_ThreeSO_Three ⁻) Was mixed with the acetonitrile solution. Poly
Thiophene monomer unit / Ag⁺(CF_ThreeSO_Three ⁻)
A mixed solution so that the final composition ratio of is 1/1 (molar ratio)
Was prepared. Comb-shaped electrodes are formed from the mixed solution
Apply it on the substrate, and use the solvents chloroform and acetonit
Evaporate tolyl and polythiophene and Ag⁺(CF
_ThreeSO_Three ⁻) Was formed on the substrate. Electric
Measure the current with a pressure sweep to obtain the resistance value.
The thickness of the comb electrodes was determined with a thickness meter. Use those results
And polythiophene and Ag⁺(CF_ThreeSO_Three ⁻) With
The volume conductivity of the mixture was calculated. This silver salt, Ag
⁺(CF_ThreeSO_Three ⁻) Is not present, these polys
The volume conductivity of thiophene is 10^-10(Scm ^-1)
It was degree. This silver salt coexists in the polythiophene film
And the volume conductivity is 10^-3From 10^-2(Scm^-1)
It increased to.

FIG. 1 is calculated by the above method,
Polythiophene-Ag⁺(CF_ThreeSO _Three ⁻) Mixture membrane body
The relationship between the product conductivity and the type of polythiophene is shown.
It In the figure, the number on the horizontal axis indicates the polythiophene in Table 1.
Is the same as the number attached to, and the vertical axis represents the volume conductivity.
The height of the vertical bar is the volume conductivity corresponding to each polythiophene.
It represents the rate, and its height is also displayed as a number on the top of the vertical bar.
There is. In addition, the correspondence between the number of polythiophene and the structure
It is shown below.

As is apparent from FIG. 1, the volume conductivity is
It largely depends on the structure of polythiophene, especially the structure of the side chain group. Since the electron donating ability of polythiophene strongly depends on the structure of the substituent, the effective charge transfer amount between the coexisting salt and the structure of the substituent also varies, and as a result,
It was understood that such a dependency of the volume conductivity on the substituent structure occurs. As evidence of this, various polythiophenes before and after addition of Ag ⁺ (CF ₃ SO ₃ ⁻ ) (molar ratio 1:
FIG. 2 shows a remarkable change in the electronic spectrum of (added so that the composition becomes 1). In the figure, the numbers given to the absorption curves are the same as the numbers given to the polythiophenes in Table 1, the solid line shows the absorption before addition of the silver salt, and the broken line shows the absorption after addition of the silver salt.

As can be seen from the comparison between FIG. 1 and FIG. 2, the higher the absorption after addition of the silver salt extends to the low energy region, the higher the conductivity obtained. Thus, since there is a correlation between the change in the electronic spectrum and the conductivity of the polythiophene mixture, if the change in the electronic spectrum as described above due to the additive is known, the conductivity of the polythiophene due to the additive is known. You can see the increase.

[Embodiment 2] Polythione shown in Embodiment 1
Polythiophene that gives the highest conductivity
(1) (Polythiophene numbered 1 in Table 1)
Ag⁺(CF_ThreeSO _Three ⁻) In a mixture with
(Ag / polythiophene monomer unit)
The product conductivity was determined. The method for producing the film is the same as in Example 1.
It

The results are given in FIG. The abscissa of the figure represents the above molar ratio, (a) in the case where the molar ratio is 0 to 5, and (b) in the case where the molar ratio is 0 to 0.5.
The vertical axis of the figure is Log (σ / S when the volume conductivity is σ).
cm ⁻¹ ), that is, the common logarithm of the numerical value indicating the volume conductivity in Scm ⁻¹ .

As can be seen from FIG. 3, the maximum conductivity is 10 ^-1 Scm ^-1 (Log (σ / Scm) at the molar ratio of 0.25.
^-1 ) = ^-1 ) was realized. When the molar ratio became smaller than 0.25, the conductivity rapidly decreased. Also, when the molar ratio became larger than 0.25, the conductivity gradually decreased.

Example 3 The conductivity of polythiophene was remarkably improved by adding a metal salt or the like. Ag ⁺ (CF ₃ S)
Not only O ₃ ⁻ ) but also other metal salts and protic acids have been realized. The cation component of the metal salt or protonic acid is, for example, Li ⁺ , Na ⁺ , K ⁺ , Fe ^{2 +} , Fe.
³⁺ , Cu ⁺ , Cu ²⁺ , Ag ⁺ , Zn ²⁺ , Eu ³⁺
Alternatively, it is H ⁺ , and the anion component is ClO ₄ ⁻ , BF
₄ ^-, B _{(phenyl) 4} ^-, B (pentafluorophenyl)
₄ ^-, B (3,5-bis (trifluoromethyl) _{phenyl) 4}
⁻ , B (p-chlorophenyl) ₄ ⁻ , B (p-fluorophenyl) ₄ ⁻ , trifluoromethanesulfonate ion or camphorsulfonate ion, the maximum conductivity is Ag ⁺ (CF ₃ SO ₃ ⁻ ). When using
^{From −1} Scm ⁻¹ , at least 10 ⁻⁶ Scm ⁻¹ was realized.

As described above, when polythiophene having one or two alkoxy groups such as methoxy group introduced into the thiophene ring was used, such remarkable improvement in conductivity was recognized. The effect of such an alkoxy substitution is that the introduction of an alkoxy group
It was understood that this is because the electron-donating ability of polythiophene was increased and effective charge transfer occurred between the polythiophene and the coexisting salt.
The cyclic ether structure of polythiophene (5) (polythiophene numbered 5 in Table 1) has the same bond form as the above alkoxy group, that is, two carbon-oxygen-carbon bonds of the thiophene ring. Therefore, it is considered to have an effect of increasing the electron donating ability equivalent to two alkoxy groups.

Evidence of charge transfer due to the addition of the metal salt is recognized by the significant change in the electronic spectrum before and after the salt addition. An example of such a change is shown in FIG.

In FIG. 4, when various metal salts were added to polythiophene (1) (polythiophene with number 1 in Table 1) in a mixed solvent of chloroform-acetonitrile in an equimolar amount to the monomer unit of polythiophene. The change in the electronic spectrum is shown for each metal salt. The horizontal axis of the figure is the photon energy, and the vertical axis is the molecular extinction coefficient [cm ⁻¹ M ⁻¹ ], and the molar concentration M in this case is the molar concentration of the monomer unit of polythiophene. In the figure, curve a is the curve before addition of the metal salt, curve b is the case of addition of Na ⁺ B (phenyl) ₄ ⁻ , curve c.
Is added Na ⁺ B (p-fluorophenyl) ₄ ⁻ , the curve d is K ⁺ B (p-chlorophenyl) ₄ ⁻ , and the curve e is Li ⁺ B (pentafluorophenyl) _{4 −.}
^In the case of addition of ⁻ , the curve f is in the case of adding Na ⁺ B (3,5-bis (trifluoromethyl) phenyl) ₄ ⁻ , and the curve g is in the case of adding Zn ²⁺ (CF ₃ SO ₃ ⁻ ) _2. , Curve h is the case where Ag ⁺ CF ₃ SO ₃ ⁻ is added, curve i is A
When g ⁺ ClO ₄ ⁻ is added, the curve j is Cu ⁺ CF ₃
When SO ₃ ⁻ is added, the curve k is Fe ²⁺ (ClO ₄
^- ) ₂ is added, the curve m is Fe ³⁺ (ClO ₄ ⁻ )
_{When 3} is added, the curve n is Cu ²⁺ (CF ₃ SO ₃ ⁻ )
The electronic spectra when ₂ is added are shown respectively.

As can be seen in FIG. 4, polythiophene
When various metal salts are added to (1), the absorption peak near 0.24 eV of polythiophene (1) shifts to the high energy side and becomes low, and a new absorption peak appears on the low energy side. From this, polythiophene (1)
It can be seen that charge transfer occurs between the metal salt and various metal salts, and it is also found that the conductivity is improved by mixing these metal salts with polythiophene (1).

[Example 4] Li ⁺ B which is one of metal salts
(Pentafluorophenyl) ₄ ^- improvement of the conductivity of the polythiophene by addition (5) (polythiophene numbered 5 in Table 1), as follows, was also confirmed in the electronic spectrum.

FIG. 5 shows a change in electronic spectrum when Li ⁺ B (pentafluorophenyl) ₄ ⁻ was added to polythiophene (5) in a mixed solvent of chloroform-acetonitrile by changing the addition amount. In the figure, a curve p shows an electron spectrum before adding a salt, and curves q, r,
s, t, u are 0.93, 5.11, 2 of salt, respectively.
The electronic spectrum when adding 5.36, 46.62, 97.10 mg is shown. In this case, 97.10m
The addition of g of salt is equivalent to that of the polythiophene (5) monomer unit 1
This corresponds to the addition of 0.25 mol of salt, based on mol.

As can be seen in FIG. 5, polythiophene
To (5) Li ⁺ B _{(pentafluorophenyl) 4} ^- the addition of, polythiophene (5) Li ⁺ B to monomer units of _{(pentafluorophenyl) 4} ^- molar ratio of 0
To 0.25 from polythiophene (5)
The absorption peak near 0.23 eV becomes lower while shifting to the high energy side, and a new absorption peak appears on the low energy side. From this, it was found that charge transfer occurred between polythiophene (5) and Li ⁺ B (pentafluorophenyl) ₄ ^−, and polythiophene (5) had L
It can also be seen that the conductivity is improved by mixing i ⁺ B (pentafluorophenyl) ₄ ⁻ .

[Example 5] The improvement of the conductivity of polythiophene (5) by the addition of camphorsulfonic acid, which is one of the protic acids, was confirmed by the electronic spectrum as shown below.

FIG. 6 shows the change in electronic spectrum when camphorsulfonic acid was added to polythiophene (5) in a mixed solvent of chloroform-acetonitrile at various amounts. In the figure, the electronic spectrum before addition of acid is displayed as “no acid added”, and the electronic spectrum after addition of acid is displayed as the molar ratio of the monomer unit of polythiophene (5) and the acid, respectively. There is.

As can be seen in FIG. 6, polythiophene
As the molar ratio of the monomer unit of (5) to camphorsulphonic acid changed from 12: 1 to 12: 5, as the acid increased, 0.23 eV of polythiophene (5)
The absorption peak in the vicinity decreases while shifting to the high energy side, and a new absorption peak appears on the low energy side. From this, it was found that charge transfer occurred between polythiophene (5) and camphorsulfonic acid, and that conductivity was improved by mixing camphorsulfophonic acid with polythiophene (5). I also understand.

[Comparative Example 1] A comparative experiment was conducted using polyalkylthiophenes (wherein the alkyl chain is n-hexyl, n-octyl, n-decyl, etc.) soluble in an organic solvent available from Aldrich (USA). went.

Chlorophos of poly (n-hexylthiophene)
Rum solution and Ag, which is one of the metal salts ⁺CF_ThreeSO_Three ⁻of
Mixed with acetonitrile solution. Polythiophene
Nomer unit / Ag⁺CF_ThreeSO_Three ⁻Has a final composition ratio of 1:
It was adjusted to 1 (molar ratio). Comb the solution
Apply it on the substrate on which the electrode is formed, and
Evaporate L-form and acetonitrile to give polythiophene.
En and Ag⁺(CF_ThreeSO_Three ⁻) Substrate film with a mixture of
Formed on top. Resistance is measured by measuring current with voltage sweep
Then, determine the size of the comb-shaped electrode with a film thickness meter separately.
It was Using the results, polythiophene and Ag⁺CF_Three
SO_Three ⁻The volume conductivity of the mixture was calculated. This silver salt
Noguchi Ag⁺(CF_ThreeSO_Three ⁻) Is not present, this
The volume conductivity of polythiophene is 10^-9Scm^-1Degree
It was degree. This silver salt coexists in the polythiophene film
In this case, the volume conductivity is 10^-7Scm^-1Increase only
I didn't. In addition, other poly (n-alkylthiophenes)
Also when using, the conductivity is similarly improved by adding salt.
Is 10^-7Scm^-1It was about.

[Comparative Example 2] Volume conductivity of a thin film prepared by using poly (ethylenedioxathiophene) (common name PEDT) (counter anion is polystyrene sulfonate) dispersed in water, which is available from Aldrich (USA). The rate is as high as 10 ^-1 Scm ^-1 , but the thiophene content of the dispersion is as low as 1%, so it is necessary to evaporate a large amount of water to form the thin film, and the surface of the formed thin film has irregularities. Was given.

In the above-mentioned Examples 1 to 3, a mixed solution of polythiophene and a metal salt or a protonic acid was applied to a substrate and the solvent was evaporated to form a thin film. However, a solution containing only polythiophene was used to form a thin film. After forming, touch the thin film with a solution of metal salt or protic acid,
A thin film of a mixture of polythiophene and a metal salt or a protic acid may be obtained by permeating the thin film with a metal salt or a protic acid. In this case, it is desirable to use a solvent that does not dissolve the already formed thin film of polythiophene as the solvent of the solution of the metal salt or the protonic acid.

As is clear from the comparison between Examples 1 to 3 and Comparative Examples 1 and 2, there are problems in constructing an electronic functional device using a conductive polythiophene by carrying out the present invention, namely, It can be seen that the problems of control of conductivity, conduction carrier concentration and mobility, simplicity of film production, and reproducibility are solved. That is, it becomes possible to easily form a conductive thin film having a controlled conductive property simply by spin-coating an organic solvent solution of the conductive composition according to the present invention, and as a result, the conductive polythiophene is used. The problem in building the electronic functional device that had been used is solved.

Although the polythiophenes shown in Table 1 are used in the above examples, the polythiophene effectively used in the present invention is not limited to this, and the following general formula 1 or general formula 2 is used. Any polythiophene represented by

[0043]

[Chemical 3] Here, at least one of R ₁ and R ₂ is an alkoxy group, one of R ₁ and R ₂ may be hydrogen, and at least one of R ₃ and R ₄ is It is an alkyl group, and one of R ₃ and R ₄ may be hydrogen, and n is an integer of 10 or more and 100000 or less.

When at least one of R ₁ and R ₂ in the above general formula 1 is an alkoxy group, the electron donating ability of polythiophene is enhanced, and significant charge transfer with a coexisting metal salt or protonic acid occurs. Occurs, and as a result, high conductivity is achieved. In addition, the above alkoxy groups increase the solubility of polythiophene in organic solvents,
Expand the range of solvent selection and increase the convenience of polythiophene thin film formation by solution coating.

The polythiophene represented by the general formula 2 is considered to have a cyclic ether structure having an effect of increasing the electron donating ability equivalent to two alkoxy groups, and the substituent R _{3 in the} cyclic ether structure is present. When at least one of R ₄ and R ₄ is an alkyl group, the solubility of polythiophene in an organic solvent is increased, the range of solvent selection is expanded, and the convenience of preparing a polythiophene thin film by solution coating is increased.

Further, n in the general formulas 1 and 2 is preferably 10 or more and 100,000 or less. When n is less than 10, the mechanical strength of the polythiophene film becomes insufficient, and when it exceeds 100,000, the solubility of the polythiophene in the solvent decreases, so that both are not preferable.

In the above-mentioned Examples 1 to 5, various kinds of compounds are used as the compound which causes charge transfer with polythiophene, but the compounds effectively used in the present invention are not limited to these. Generally, it may be a metal salt or a protic acid.

In summary, the polythiophene, which is a constituent element of the conductive composition according to the present invention, is soluble in an organic solvent and has a high electron donating ability. Therefore, if this polythiophene is used, a solution is obtained. By forming the film from above, a conductive film having a high conductivity can be easily formed on the substrate, and the conductive film can be easily formed in the process of manufacturing the functional element.

Specifically, by simply spin-coating the solution of the conductive composition of the present invention on the ITO substrate of the electroluminescent device material, the conductive material having a high surface smoothness and a high transparency for visible light. A thin film can be easily formed, and the application of the present invention can contribute to a simple method for producing a good electroluminescent device.

The conductive composition according to the present invention is also useful as an electron beam resist material. That is, when a conductive layer is formed by spin-coating the conductive composition according to the present invention on a negative resist material or a hosi-type resist material which has already been used, a drawing by surface charging generated at the time of electron beam drawing can be performed. Since the disturbance is suppressed, it is possible to perform electron beam drawing with extremely high accuracy and high throughput. Moreover, since the conductive composition according to the present invention also has dry etching resistance, it can be used alone or as a conductive electron beam resist material. In other words, if the side chain group is decomposed and released by electron beam irradiation, the solubility of polyalkoxythiophene at the time of development is lowered, and therefore it can be used as a negative resist material. Since the molecular weight of is decreased and the solubility at the time of development is improved, it can be used as a positive resist material.

[0051]

By carrying out the present invention, it becomes possible to provide a conductive composition which can be produced easily and inexpensively by using polythiophene as a constituent component.

According to the present invention, polythiophene having at least one alkoxy group or thiophene having an alkyl-substituted cyclic ether structure is mixed with a metal salt or a protic acid, or a polythiophene film having an alkoxy group is mixed with these metals. The conductive composition can be easily provided simply by contacting with a solution of a salt or a protic acid.

[Brief description of drawings]

FIG. 1 Various polythiophenes and Ag ⁺ CF ₃ SO ₃ ^−.
It is a figure which shows the volume conductivity of the mixture with.

FIG. 2 shows Ag ⁺ CF ₃ SO ₃ ^{− in} various polythiophenes.
It is a figure which shows the change of the electronic spectrum before and after addition of when is added.

FIG. 3 shows polythiophene (1) and Ag ⁺ CF ₃ SO ₃ ^−.
It is a figure which shows the relationship between the mixed composition ratio of and and volume conductivity.

FIG. 4 is a view showing an electronic spectrum (in a chloroform-acetonitrile mixed solvent) of a mixture of polythiophene (1) and various metal salts.

FIG. 5 is a diagram showing a change in electron spectrum (in a chloroform-acetonitrile mixed solvent) when Li ⁺ B (pentafluorophenyl) ₄ ⁻ is added to polythiophene (5) while changing the addition amount.

FIG. 6 is a view showing a change in an electronic spectrum (in a chloroform-acetonitrile mixed solvent) when camphorsulfonic acid is added to polythiophene (5) while changing the addition amount.

[Explanation of symbols]

1 to 7 ... Numbers given to polythiophene.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Nakajima             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Kazuaki Furukawa             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Yoshiaki Kashimura             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F-term (reference) 4J002 CE001 DE176 DG046 DK006                       EY016 FD116 GT00

Claims (2)

[Claims] 1. A conductive composition which is a mixture of polythiophene represented by the following general formula 1 or 2 and a metal salt or a protic acid. [Chemical 1] Here, at least one of R ₁ and R ₂ is an alkoxy group, one of R ₁ and R ₂ may be hydrogen, and at least one of R ₃ and R ₄ is It is an alkyl group, and one of R ₃ and R ₄ may be hydrogen, and n is an integer of 10 or more and 100000 or less. 2. The conductive composition according to claim 1, wherein the cation component of the metal salt or protonic acid is Li ⁺ ,
Na ⁺ , K ⁺ , Fe ²⁺ , Fe ³⁺ , Cu ⁺ , C
u ²⁺ , Ag ⁺ , Zn ²⁺ , Eu ³⁺ or H ⁺ , and the anion components are ClO ₄ ⁻ , BF ₄ ⁻ , B (phenyl) ₄ ⁻ , B (pentafluorophenyl) ₄ ⁻ , B (3,5). -
Bis (trifluoromethyl) phenyl) ₄ ⁻ , B (p-chlorophenyl) ₄ ⁻ , B (p-fluorophenyl) ₄ ⁻ , CF
₃ SO ₃ ⁻ or a camphorsulfonate ion, which is a conductive composition.