JPH07247437A - Poly(hydrosilane) composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition suitable for an electrically- conductive material, having high electrical conductivity and light-transforming material by doping a polysilane of a specific formula with an oxidizing material. CONSTITUTION:A polysilane of the formula [R is a (substituted) alkyl or an aryl] is doped with an oxidizing material to give the objective composition. Iodine or ferric oxide is preferably used as the oxidizing material and the doping is carried out by a method such as vapor-phase doping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polysilane composition suitable as a light conversion material and a conductive material.

[0002]

BACKGROUND OF THE INVENTION Polysilanes have characteristic optical properties due to the σ-conjugated structure of the silicon-silicon main chain and have the highest carrier mobility in amorphous materials. It is expected to be applied to conductive materials. However, the electric conductivity of generally known polysilane remains at an extremely low level of 10 ⁻⁸ to 10 ⁻⁶ S / cm. On the other hand, in recent years, polysilanes having an aromatic amine-containing side group have been synthesized by the Wurtz reaction, and it has been found that the conductivity is improved 10,000 times or more as compared with ordinary polysilanes by doping (Eiichi Tabei). In addition, Japanese Patent Application No. 5-53043;
Eiichi Tabei et al., Proceedings of 42nd Annual Meeting of Polymer, Vol. 42 No. 3, 738 (1993)). On the other hand, from the viewpoint of theoretical calculation, it has been reported that the band gap of perfluoropolysilane is smaller than that of polysilane (Y. Yamaguchi, Synth. Met., 5).
2, 51 (1992)), which is expected to be effective in improving conductivity, but there is no actual synthetic example.

The synthesis of the halogen side chain polysilane is considered to be derived from the hydrogen side chain polysilane (JP Ba.
novetz et. al. J. Am. Chem. So
c. , (1993), 115 , 2540), the synthesis of polysilanes having a hydrogen group on the side chain uses some of the Wurtz reaction, but some Si-H
Has been found to occur. Synthesis of polysilane by the dehydrogenative condensation method is not concerned about decomposition of side chain hydrogen groups, but it is said that improvement in the degree of polymerization is a problem.
The main focus of the research was to increase the activity of the catalyst to obtain a high polymer and to analyze the reaction mechanism, and almost no research on electrical conductivity was conducted.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a polysilane composition having excellent conductivity.

[0005]

Means and Actions for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that polysilane having a side chain hydrogen group represented by the following general formula (1) is an oxidizing substance, In particular, by treating with a halogen-containing dopant, it has been found that it imparts excellent conductivity and exhibits a conductivity that is about 100 to 10,000 times higher than that of ordinary polysilane, and has completed the present invention.

[0006]

[Chemical 2] (However, in the formula, R represents a substituted or unsubstituted alkyl group or aryl group.)

Therefore, the present invention provides a polysilane composition comprising the polysilane of formula (1) doped with an oxidizing substance.

The present invention will be described in more detail below. The polysilane used in the polysilane composition of the present invention is represented by the following formula (1).

[0009]

[Chemical 3]

Here, R represents a substituted or unsubstituted alkyl group or aryl group, and the alkyl group has 1 to 1 carbon atoms.
20, more preferably 1 to 6, and the aryl group preferably has 6 to 20 carbon atoms, more preferably 6 to 10 carbon atoms. Specifically, methyl, ethyl, propyl, butyl,
Examples thereof include alkyl groups such as hexyl and aryl groups such as phenyl and naphthyl. The substituted alkyl group has 1 to 1 carbon atoms.
20, more preferably, those in which a part or all of the hydrogen atoms of the alkyl group of 1 to 6 are substituted with halogen atoms such as fluorine and chlorine. Examples of the substituted aryl group include those represented by the following formula.

[0011]

[Chemical 4]

Here, X is a halogen atom such as Cl or Br, a methyl group, an ethyl group or the like, preferably having 1 to 1 carbon atoms.
0, especially 1 to 6 alkyl groups, trifluoropropyl groups and other C _m F _{2m + 1} (m is preferably 1 to 4, especially 1 to 2) fluoroalkyl groups, methoxy groups, ethoxy groups, etc. It is preferably an alkoxy group having 1 to 10 carbon atoms, particularly 1 to 4 carbon atoms, a substituted or unsubstituted amino group, an acyl group, or an aldehyde group. Y represents a hydrogen atom, the same halogen atom as described above, an alkyl group, a fluoroalkyl group, a substituted or unsubstituted amino group, an acyl group, or an aldehyde group. Examples of the substituted amino group include an alkylamino group in which one or two hydrogen atoms of the amino group are substituted with an alkyl group having 1 to 10 carbon atoms, particularly 1 to 4 carbon atoms.
Further, m is an integer of 1 to 5 and k is an integer of 0 to 4, and k + m =
1 to 5.

The polysilane used in the present invention can be used regardless of its production method and molecular weight as long as its side chain has a hydrogen group. Further, the structure of the polymer (oligomer) may be linear or cyclic, and the performance is sufficiently exhibited even if the polymerization degree is about 10 which can be easily produced by ordinary dehydrogenative condensation. However, from the viewpoint of film-forming property, it is desirable that the polymer is a solid polymer at around room temperature. From such a point, n in the formula (1) is 3 or more, preferably 6 or more, more preferably 10 or more. In this case, the upper limit of n is not particularly limited, but is preferably large as long as the solubility in the solvent is not impaired, and as the polysilane, those having a weight average molecular weight of 400 or more, particularly 1000 or more are preferably used.

When the above polysilane is obtained by the dehydrogenative condensation reaction of trihydrosilane, it can be carried out at room temperature or under heating conditions using a catalyst for the dehydrogenative condensation reaction. As the catalyst, any catalyst used in a general dehydrogenative condensation reaction can be used, but a zirconohine or titanocene-based catalyst is particularly preferable (Aitken, C., Har.
rod, J.D. F. , Samuel, F, J .; Am. Ch
em. Soc. , (1986), 108 , 4059).
The amount of the catalyst used is a normal amount, and is preferably 0.001 to 20% by weight, and particularly preferably 0.01 to 1% by weight, based on the silane.

A solvent is not essential for this reaction, but an aprotic solvent such as tetrahydrofuran (THF), toluene, which does not react with hydrosilanes,
It is preferable to use benzene, hexane or the like. The reaction temperature is 0 ° C to 200 ° C, particularly preferably room temperature to 110 ° C,
The reaction time is usually 3 to 240 hours, especially 12 to 70 hours.

Oxidizing substances for doping the polysilane include halogens such as chlorine, bromine and iodine, tin chloride, transition metal chlorides such as ferric chloride,
Although Lewis acids such as antimony pentafluoride and arsenic pentafluoride are effective, it is preferable to dope with iodine or ferric chloride that is safe and easy to handle. The doping method includes (1) so-called vapor phase (or dry type) doping in which iodine or ferric chloride is exposed to a vapor atmosphere, and (2) in a solution in which iodine or ferric chloride is dissolved in an inert solvent. Wet doping to dip the polymer,
(3) When the polymer is dissolved in a solution in which iodine or ferric chloride is dissolved, co-doping is used, in which a film is formed into a film or a coating film by dry film-forming from the solution and at the same time, doping is performed.

In vapor phase doping, the doping rate can be controlled by controlling the temperature of the dopant atmosphere and the dopant partial pressure. Generally the temperature is −
It is preferably carried out in the range of 30 to 200 ° C. If it is less than that, the doping rate is slow, and if it is more than that, the polymer is deteriorated during doping, which is not preferable. The dopant partial pressure is preferably in the range of 0.001 mmHg to 5 atm. Below that, the doping rate is slow, and above that, even if the pressure is increased, the doping rate does not increase. It should be noted that iodine is promptly doped at room temperature and atmospheric pressure, but in the case of ferric chloride, the vapor pressure is low, so that the doping condition is different from that of iodine. Ferric chloride doping is generally preferably carried out at a temperature in the range of 50 to 300 ° C. If it is less than that, the doping rate is slow, and if it is more than that, the polymer is deteriorated during doping, which is not preferable. Doping is 0.001m
It is preferably carried out in the range of mHg to 1 atm. Below that, it takes a long time to reach that pressure, which is not economical, and above that, ferric chloride has a boiling point of 319 ° C. at atmospheric pressure, and the doping rate is very slow.
The dopant partial pressure of ferric chloride is more preferably 0.1 to 10 mmH in order to effectively increase the conductivity of the polymer.
It is carried out at a pressure of g and a temperature in the range of 50 to 200 ° C. According to this method, a conductive polymer can be produced with a very simple operation using ferric chloride having low toxicity without using a flammable solvent.

[0018]

EXAMPLES Hereinafter, the present invention will be specifically shown by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

The average molecular weights of the following polymers are GP
The polystyrene equivalent weight average molecular weight by C is shown. Further, the electrical conductivity was measured by measuring the DC resistance by a four-terminal method while vapor-doping the spin-coated film, and when the stable value was obtained, it was used for calculating the conductivity.

Example 1 Poly (phenylsilane) synthesized by dehydrogenative polymerization of phenylsilane (M _w = 65)
A THF solution of 0, M _n = 640) was spin-coated on the substrate, and the conductivity was measured while performing vapor-phase iodine doping. As a result, it was improved to 4 × 10 ⁻³ S / cm.

Example 2 Poly (phenylsilane) synthesized by dehydrogenative polymerization of phenylsilane (M _w = 65)
A THF solution of 0, M _n = 640) was spin-coated on the substrate, and the conductivity was measured while performing vapor phase iron chloride doping. As a result, it was 7 × 10 ⁻⁵ S / cm.

Example 3 Poly (β-naphthylsilane) (M synthesized by dehydrogenation polymerization of β-naphthylsilane)
A THF solution of _w = 1170, M _n = 1140) was spin-coated on the substrate, and the conductivity was measured while performing vapor-phase iodine doping. As a result, it was 4 × 10 ⁻⁴ S / cm.

Example 4 Poly (p-tolylsilane) synthesized by dehydrogenative polymerization of p-tolylsilane (M _w =
A THF solution of 930, M _n = 900) was spin-coated on the substrate, and the conductivity was measured while performing vapor-phase iodine doping, and it was 5 × 10 ⁻⁵ S / cm.

Example 5 Poly (p-dimethylaminophenylsilane) synthesized by dehydrogenative polymerization of p-dimethylaminophenylsilane (M _w = 1170, M _n = 11)
The THF solution of 30) was spin-coated on a substrate, and the conductivity was measured while performing vapor-phase iodine doping.
It was 7 × 10 ⁻³ S / cm.

Comparative Example 1 Poly (methylphenylsilane) by the Wurtz reaction (M _w = 46000, M _n = 1100)
The THF solution of 0) was spin-coated on a substrate, and the conductivity was measured while performing vapor phase iodine doping.
It was 1.3 × 10 ⁻⁶ S / cm.

[Comparative Example 2] A THF solution of poly (dibutylsilane) (M _w = 21000, M _n = 12000) by the Wurtz reaction was spin-coated on a substrate, and the electrical conductivity was measured while performing vapor-phase iodine doping. By the way, 3.5 ×
It was 10 ⁻⁶ S / cm.

The production examples of the polysilanes of Examples 3 and 4 are shown below as reference examples.

Reference Example 1 2.626 g (17.35 mmol) of p- (N, N-dimethylanilino) silane was added to T
1 in a sealed tube in the presence of 3 mg of zirconocene catalyst in HF
When reacted at 05 ° C. for 72 hours, poly (p-dimethylaminophenylsilane) with a yield of 94.3% and M _w = 1,330 and M _n = 1,260 was obtained.

[Reference Example 2] According to Reference Example 1, 1.225 g (7.74 mmol) of β-silylnaphthalene was added to TH.
10 mg in a sealed tube in the presence of 4 mg of zirconocene catalyst in F.
When reacted at 5 ° C for 72 hours, the yield was 90.8% and M
Poly (β-naphthylsilane) having _w = 1,170 and M _n = 1,140 was obtained.

[0030]

EFFECT OF THE INVENTION The polysilane composition of the present invention has a high electric conductivity, and therefore is suitable for use as a light conversion material and a conductive material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Motoo Fukushima 3-2-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Corporate Research Center, Shin-Etsu Chemical Co., Ltd. (72) Shigeru Mori Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture 3-2-1, Shin-Etsu Chemical Co., Ltd. Corporate Research Center

Claims (1)

[Claims] 1. A polysilane represented by the following general formula (1): (However, R in the formula represents a substituted or unsubstituted alkyl group or aryl group.) A poly (hydrosilane) composition characterized by being doped with an oxidizing substance.