JPH03212977A - Substrate for solar cell - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a solar cell substrate that improves the output characteristics of a solar cell by scattering incident light and effectively utilizing the light absorbed by the active layer. Regarding.

[Technology background]

A method of improving the output characteristics of a solar cell using a light-reflecting substrate by forming the substrate surface as a rough surface with unevenness and increasing the optical path length of long-wavelength light having a particularly small absorption coefficient is, for example, , USP No. 4,126
．． It is suggested in column 7, lines 3 to 8 of Specification No. 150 (RCA), and is disclosed in Japanese Patent Application Laid-open No. 152276 (Sho 56-152276) (Original University).
It is also mentioned in . Furthermore, Japanese Patent Application Publication No. 5910418
No. 5 (Exxon Research and Engineering Company) details the optical effects of a roughened substrate.

In addition, the Journal of Applied Physi
cs) Volume 62, No. 7, Page 3016 (Thomas C.
, Paulick.

Oct '87), Texture of Silver
The optical reflection properties of amorphous silicon solar cells using e) are treated mathematically.

The method for forming the uneven surface is described in Japanese Patent Application Laid-Open No. 54-1535.
No. 88 (National Patent Development Corporation) discloses wet etching, and JP-A-58-159383 (Energy Conversion Devices) discloses sandblasting and
The facet formation method and co-evaporation method were published in JP-A-59-1468.
In Publication No. 2 (Electrolytic Foil Industrial Area), aluminum surface roughening by direct current electrolytic etching or chemical etching method was carried out, and in JP-A-59-82778 (Energy Conversion Devices), sputter etching method/sandblasting method was used as mentioned above. JP-A-59-104185 discloses a lithography method, a transparent conductor deposition method using pyrolysis spray, an ion beam simultaneous deposition method, and an etching method, respectively.

In addition, as a method using materials that inherently tend to form unevenness, there is also the organic insulating layer and the metal reflective layer provided thereon, as disclosed in Japanese Patent Application Laid-open No. 58-180069 (Director of the Agency of Industrial Science and Technology), and a metal reflective layer provided thereon.
There is a ceramic substrate published by No. 9-213174 (Director of the Agency of Industrial Science and Technology).

Characteristics desired for the substrate of solar cells, especially amorphous silicon solar cells, are: ○ It has an uneven structure to effectively utilize long wavelength light.

O The uneven structure in the previous section does not cause a short circuit in the solar cell.

○ The substrate composition does not penetrate into the solar cell and deteriorate the characteristics of the solar cell.

However, the above-mentioned prior art still has some inadequacies.

That is, there is a problem in that the metal atoms constituting the uneven structure migrate into the amorphous silicon layer, changing the doping profile of the impurity layer and forming recombination centers, resulting in a decrease in output current. .

In addition, sintered powders such as ceramics may be used as the base, or smooth surfaces may be roughened by etching or other methods.
When a metal film with an uneven structure is formed, the uneven structure tends to be irregular or have sharp edges, and if a solar cell is formed directly on the film, the characteristics of the solar cell may vary and short circuits may occur. There was a problem that problems such as the following occurred more easily.

Furthermore, when an amorphous silicon film is formed directly on a metal surface, there is a problem in that peeling easily occurs from the interface, reducing the yield of solar cells.

[Purpose of the invention]

The present invention has been made in view of the above points, and the present invention provides a substrate for a solar cell having an uneven surface, which has an uneven structure for effectively utilizing long wavelength light. The present invention aims to provide a solar cell substrate in which the Fi-based composition does not cause a short circuit in the solar cell, and the Fi-based composition does not penetrate into the solar cell and deteriorate the characteristics of the solar cell.

A further object of the present invention is to provide a solar cell substrate with good adhesion between the solar cell substrate and the semiconductor layer constituting the solar cell.

Furthermore, an object of the present invention is to improve the reflection of light from the metal surface of a solar cell substrate.

[Structure of the Invention] To achieve the above-mentioned object, the present invention has an uneven surface of 0.1 μm or more on a conductive support, and has a general formula [I]
and the weight average molecular weight is 6,000 to 200,000
It is characterized by providing a layer composed of a novel and hitherto unknown polysilane compound (hereinafter simply referred to as a polysilane compound).

R+ Ri A -Bi-FT-Ichiko 31 → Ko A'...N
) Rz Ra (wherein, R1 is an alkyl group having 1 or 2 carbon atoms, R
2 is an alkyl group having 3 to 8 carbon atoms, a cycloalkyl group,
Aryl group or aralkyl group, R2 has 1 to 4 carbon atoms
R4 represents an alkyl group having 1 to 4 carbon atoms, A and A' each represent an alkyl group having 4 to 12 carbon atoms.
are an alkyl group, a cycloalkyl group, an aralkyl group, or an aralkyl group, and both may be the same or different.

n and m are molar ratios indicating the proportion of each 1,000-mer number to the total monomers in the polymer, n + m = 1
Therefore, 0<n≦1.0≦m<l. ) Figure 1 shows a PIN using the solar cell substrate according to the present invention.
1 is a diagram schematically showing the general structure of a type amorphous silicon solar cell. The present invention will be explained below using a PIN type solar cell for convenience, but the present invention can be applied to other types of solar cells including the Shaw/Toki type, and is not limited thereto.

Examples of the material of the support 101 that can be applied to the present invention include plates and films made of molybdenum, tungsten, titanium, cobalt, chromium, iron, copper, tankle, niobium, zirconium, aluminum metals, or alloys thereof. It will be done. Among these, stainless steel, nickel-chromium alloys, dichloride, tantalum, niobium, zirconium, titanium metals and/or alloys are particularly preferred from the viewpoint of corrosion resistance. In addition, these metals and/or alloys can be formed on films or sheets of synthetic resins such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, glass, ceramics, etc. It is also possible to use

The thickness of the support 101 can be made thin as long as it can function as a support, but from the viewpoint of manufacturing, handling, mechanical strength, etc., the thickness is usually 10 μm.
m or more.

A reflective conductive layer 102 is provided on the support 101. Materials for the reflective conductive layer 102 that can be applied to the present invention include metals with high optical reflectivity such as gold, silver, copper, and aluminum. can be mentioned.

Further, if the optical reflectivity of the support 101 is sufficiently high, it is also possible to have a structure in which the reflective conductive layer 102 is omitted.

The surface of the reflective conductive layer 102 may be a smooth surface or an uneven surface.The surface of the reflective conductive layer 102 may be a smooth surface or an uneven surface. This can be easily obtained by adjusting the temperature of 101. Generally, a stronger uneven surface can be obtained when the temperature of the support 101 is set higher.

A polysilane layer 103 made of the polysilane compound is formed on the reflective conductive layer 102 .

The support 101, the reflective conductive layer 102, and the polysilane layer 103 are collectively referred to as a substrate 104.

The polysilane layer 103 used in the solar cell substrate 104 of the present invention is based on knowledge obtained as a result of extensive research to overcome the problems of the prior art. That is, by composing the uneven layer having the uneven surface with a polysilane compound, the uneven surface has a light confinement effect while preventing metal atoms and the like from penetrating into the amorphous silicon layer, and preventing sunlight caused by the uneven structure from penetrating into the amorphous silicon layer. It is possible to prevent battery leakage (<, and even if a leak does occur, its negative effects can be kept to a minimum.

The polysilane compound used in the present invention has a weight average molecular weight of 6,000 to 200,000, but from the viewpoint of solubility in a solvent and film forming ability, a more preferable one has a weight average molecular weight of 8,000 to 120.
000, and the optimal one has a weight average molecular weight of 1
0000 to 5oooo.

Those with a weight average molecular weight of 6,000 or less do not exhibit the characteristics of polymers and have no film-forming ability, and those with a weight average molecular weight of more than zooooo have poor solubility in solvents, making it difficult to form the desired film. Have difficulty.

Further, in the above-mentioned polysilane compound represented by the above-mentioned general formula (r) used in the present invention, when particularly toughness is desired for the film to be formed, the terminal groups A and A' are
Desirably, the group is selected from the group consisting of an alkyl group having 5 to 12 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, an aralkyl group, and an aralkyl group, and in this case, it is most preferably used in the present invention. In the polysilane compound, the terminal groups A and A' are groups selected from an alkyl group having 5 to 12 carbon atoms and a cycloalkyl group having 5 to 12 carbon atoms.

The above-mentioned polysilane compound used in the present invention can be synthesized as follows.

That is, under a high-purity inert atmosphere free of oxygen and moisture, a dichlorosilane monomer is brought into contact with a condensation catalyst made of an alkali metal to perform halogen elimination and condensation polymerization to synthesize an intermediate polymer. By separating the intermediate polymer from unreacted monomers and reacting a predetermined halogenated organic reagent with the intermediate polymer in the presence of a condensation catalyst made of an alkali metal to condense an organic group at the end of the polymer. be synthesized.

In the above synthesis operation, the dichlorosilane monomer as the starting material, the intermediate polymer, the halogenated organic reagent, and the alkali metal condensation catalyst are all highly reactive with oxygen and moisture, so these oxygen and moisture are present. Under such an atmosphere, the desired polysilane compound described above cannot be obtained.

Therefore, the above-mentioned operation for obtaining the above-mentioned polysilane compound used in the present invention needs to be carried out in an atmosphere in which neither oxygen nor moisture is present. For this reason, care must be taken regarding the reaction vessel and all reagents used to avoid the presence of either oxygen or moisture in the reaction system. Perform substitution to prevent adsorption of moisture and oxygen into the system. In any case, the argon gas used is previously passed through a silica gel column to dehydrate it, and then the copper powder is passed through a column heated to 100° C. for deoxidation treatment before use.

The dichlorosilane monomer as a starting material is introduced into the reaction system after being distilled under reduced pressure using the above-mentioned argon gas which has been deoxygenated immediately before introduction into the reaction system.

The halogenated organic reagent and the solvent used for introducing a specific organic group are also deoxidized in the same manner as the dichlorosilane monomer before being introduced into the reaction system.

Note that the solvent is deoxidized by distilling it under reduced pressure using the deoxygenated argon gas described above, and then further dehydrating it with metallic sodium.

The above condensation catalyst is used in the form of wires or chips, and the wires or chips are formed in an oxygen-free paraffinic solvent to prevent oxidation.

The dichlorosilane monomer as a starting material used in producing the polysilane compound represented by the above general formula [I] used in the present invention has the general formula: R+Rx5iC
A silane compound represented by It or the general formula: R
A silane compound represented by zRaSiClz is selectively used.

As the above-mentioned condensation catalyst, an alkali metal capable of causing a condensation reaction by eliminating halogen is preferably used, and specific examples of the alkali metal include lithium, sodium, and potassium, with lithium and sodium being preferred.

The above-mentioned halogenated organic reagent is for introducing substituents represented by A and A', and is composed of a halogenated alkyl compound, a halogenated cycloalkyl compound, a halogenated aryl compound, and a halogenated aralkyl compound. A suitable compound selected from the group -a formula:
A-X and/or general formula: A'-X (where X is CI!
or Br), and appropriate compounds from the specific examples described below are selectively used.

General formula used when synthesizing the above intermediate polymer: RIRtSiC12 or this and general formula: RxRa
The dichlorosilane monomer represented by 5:C12 is introduced into the reaction system after being dissolved in a predetermined solvent, and a paraffinic nonpolar hydrocarbon solvent is preferably used as the solvent. Preferred examples of the solvent include n-hexane, n-octane, n-nonane, n-dodecane, cyclohexane and cyclooctane.

Since the resulting intermediate polymer is insoluble in these solvents, it is convenient to separate the intermediate polymer from unreacted dichlorosilane monomers.The separated intermediate polymer is then treated with the above-mentioned halogenated organic reagent. In this case, both are dissolved in the same solvent and subjected to the reaction. In this case, aromatic solvents such as benzene, toluene, and xylene are preferably used as the solvent.

When the desired intermediate is obtained by condensing the above-mentioned dichlorosilane monomer using the above-mentioned alkali metal catalyst, the degree of polymerization of the resulting intermediate polymer can be appropriately controlled by adjusting the reaction temperature and reaction time. However, the reaction temperature at that time is preferably set between 60°C and 130°C.

The above general formula (+) used in the present invention explained above
A desirable embodiment of the method for producing the above-mentioned polysilane compound represented by is described below.

That is, the method for producing the above-mentioned polysilane compound used in the present invention includes (i) producing an intermediate polymer, and (ii) adding substituents A and A' to the terminals of the if intermediate polymer.
It consists of a process of introducing.

The step (i) above is performed as follows.

That is, the reaction system in the reaction vessel is completely free of oxygen and moisture and is dominated by argon and maintained at a predetermined internal pressure.
Add an oxygen-free paraffinic solvent and an oxygen-free condensation catalyst,
Next, an oxygen-free dichlorosilane monomer is added, and the whole is heated to a predetermined temperature while stirring to effect condensation of the seven polymers. At this time, the degree of condensation of the dichlorosilane monomer is
The reaction temperature and reaction time are adjusted to produce an intermediate polymer with a desired degree of polymerization.

In this reaction, as shown in the reaction formula (i) below, the chloro group of the dichlorosilane monomer and the catalyst cause a desalting reaction, and the Si groups repeat condensation to form a polymer, producing an intermediate polymer. do.

Catalyst nR+Rz 5iC1lt +mR=R4SiC1x
→R+ RkoC1-鵠iHtoT--Rin-5i-Y1- CR...
(i) Rz Ra The specific reaction procedure here is to prepare a condensation catalyst (alkali metal) in a paraffinic solvent,
Dichlorosilane monomer is added dropwise while stirring under heat. The degree of polymerization is confirmed by sampling the reaction solution.

Polymerization can be easily confirmed by evaporating the sampling liquid and determining whether a film can be formed.

As the condensation progresses and a polymer is formed, it becomes a white solid that precipitates out of the reaction system. Here, it is cooled, and the solvent containing the monomer is separated from the reaction system by decantation to obtain an intermediate polymer.

Then, the fbl step is performed. That is, the chloro group at the end group of the obtained intermediate polymer is subjected to desalting condensation using a halogenated organic agent and a condensation catalyst (alkali metal), and the polymer end group is replaced with a predetermined organic group. The reaction at this time is represented by the following reaction formula (ii).

RI R1 Cl1-Hl-T----shi"Si-to1-C1+ (2A X+A' An aromatic solvent is added to and dissolved in the intermediate polymer obtained by condensation of silane monomers.Next, a condensation catalyst (alkali metal) is added, and a halogenated organic agent is added dropwise at room temperature.

At this time, in order to compete with the condensation reaction between the polymer end groups, the halogenated organic agent is added at 0.01 to 0.0% relative to the starting monomer.
Add 1x excess amount. Gradually heat to 80℃~100℃
The mixture is heated and stirred at ℃ for 1 hour to carry out the desired reaction.

After the reaction is completed, the mixture is cooled and methanol is added to remove the alkali metal of the catalyst. Next, the generated polysilane compound is extracted with toluene and purified using a silica gel column. The desired polysilane compound used in the present invention is thus obtained.

(Left below) RIRt SiCII! and R5Ra SiCR1
Note): Among the following compounds, a-2 to 16,1
8.20,21°23.24 is used for 1lIR2SiC/z, a-1°2.11.17,19,22,23
．． 25 is used for 113R4SiC1z.

(CI+3) zs iC12z -1 ((Oli)z@zsicj!z -22 ((CH3) 3C) zsic J z-5 A-X and A’-X ingredients (C)13) z(IC1lzCj! -1 CI+(CHJaCffi -2 0i(CHJsCj2 -3 CI (3 (01g) + oC1 -4 C11z (C1lz) 5Br Cll3 (CHz) Ioar -14 -15 Alkali metals are preferred as catalysts.

Lithium, sodium, and potassium are used as alkali metals. It is preferable that the shape is wire-like or chip-like to increase the surface area.

Book in polysilane specifics of Around Cll.

C3(C1+,)□ C11 (CIIJI C1l.

H3 island I3 l13 113 l13 Note); In the above structural formula, both X and Y represent a polymerized unit of a monomer. And n is X/(X+Y), and m is
Each is calculated using the formula Y/(X+Y).

Electrical resistivity can also be easily controlled by mixing appropriate impurities into the polysilane compound synthesized in this manner. As an impurity to exhibit N-type conduction, TPA (triphenyl
amtne), TMPD (N, N.

N'N' tetra methylphen
ylene diamine) and the like.

In addition, impurities for exhibiting P-type conduction include:
2, 4, 7- trinitrofluore
none +T CN Q
ino dimethane), S b F 5As
Examples include F5.

The polysilane layer in contact with the P-type semiconductor layer is preferably a P-type polysilane layer, and the polysilane layer in contact with the N-type semiconductor layer is preferably an N-type polysilane layer.

The electrical resistivity of the polysilane compound used in the present invention is appropriately determined depending on the desired purpose.

In other words, it is better to have a low electrical resistivity in order to extract the electrical energy generated by the solar cell, but a high electrical resistivity is necessary to minimize the negative effects of short circuits caused by pinholes that occur in the PIN structure. Therefore, in actual solar cells, the electrical resistivity of the polysilane layer 103 has an optimum value.

A method for forming the polysilane layer 103 using the polysilane compound synthesized by the above method as a raw material will be described below, but the present invention is not limited thereto.

Examples of the method for forming the polysilane layer 103 include a method of coating it on a support using a spinner method, a spray method, a dipping method, or the like.

In the spinner method, a support is fixed to a holder that rotates at high speed, and polysilane dissolved in an organic solvent is dropped onto the support that is rotating at high speed, and then applied uniformly onto the support using centrifugal force. , a method in which a uniform polysilane layer is formed on a support by vaporizing the solvent.

By the spinner method, the layer thickness of the polysilane layer can be controlled as desired by adjusting the viscosity of a solution of polysilane dissolved in an organic solvent and the rotation speed of the spinner. The shape of the unevenness on the polysilane layer is determined by applying the polysilane solution with a spinner and then vibrating the holder before vaporizing the solvent to form the unevenness on the polysilane layer.

The shape of the unevenness is controlled to a desired shape by the frequency and amplitude of the holder and the viscosity of the solution.

The spray method, like the spinner method, is a method in which polysilane is dissolved in an organic solvent, and a solution in which polysilane is dissolved is sprayed onto a support using a sprayer to form a polysilane layer.

The thickness of the polysilane layer is controlled to a desired thickness by controlling the viscosity of the polysilane solution, the diameter of the nozzle of the atomizer, the amount of the polysilane solution sprayed, and the like. Further, the shape of the unevenness of the polysilane layer can be controlled to a desired shape by appropriately controlling the viscosity of the polysilane solution, the nozzle diameter of the atomizer, and the like.

For example, by increasing the particle size of the mist and increasing the viscosity of the polysilane solution, the shape of the irregularities can be increased.

The dipping method is a method in which the support is immersed in the polysilane solution, and the support is pulled out of the solution to form a polysilane layer on the support.

The layer thickness of the polysilane layer by dipping is controlled by changing the viscosity of the polysilane solution and the rate at which it is pulled up from the solution. In addition, the uneven shape of the polysilane layer is
After applying a polysilane solution onto a support by dipping, the support is vibrated to form a desired shape.

The viscosity of the polysilane solution in the spinner method, spray method, and dipping method is controlled by the mixing ratio of polysilane and organic solvent, the temperature of the polysilane solution, etc.

Further, as the organic solvent for melting polysilane of the present invention,
Aromatic solvents such as benzene, toluene and xylene are preferably used.

The average layer thickness of the polysilane layer 103 used in the present invention is preferably 0.1 to 10 μm, more preferably 0.3 to 2 μm. If the layer thickness of the polysilane layer is too small, the long wavelength light that has reached the substrate cannot be effectively scattered, and the light confinement effect cannot be expected. In addition, the average spacing and roughness of the uneven structure are appropriately determined depending on the desired solar cell characteristics, but preferably the average spacing is 0.1.
~1 μm, with a roughness of 0.1-0.8 pm.

N-type amorphous silicon 11 is deposited on the substrate 104 including the polysilane layer 103 formed in this way.
105, a PIN type amorphous silicon solar cell 108 is formed, which includes an I type amorphous silicon layer 106 and a P type amorphous silicon layer 107. The solar cell 10
For the production of No. 8, sputtering, glow discharge decomposition, microwave CVD, photoCVD, and other conventional amorphous silicon film production methods can be used. Microwave CVD in terms of etc.
Law is preferable.

A transparent conductive film 109 is formed on the PIN solar cell 108 . The transparent conductive film 109 has rTo 5not
, InxOi, etc. are used. A current collecting electrode 110 is formed on the transparent conductive film 109, which can be easily formed by, for example, heating vapor deposition or sputtering. The current collecting electrode 110 is preferably made of a material that improves electrical conductivity between the transparent conductive film 109 and the external lead wA (not shown). Examples of such materials include aluminum, chromium, platinum, gold, and aluminum. These metals are
It is possible to form the transparent electrode 109 using a mask.

[Production example of polysilane compound used in the present invention]

Below, the polysilane compound used in the present invention will be explained with reference to a specific production example, and the usefulness of the polysilane compound will also be explained.

In addition, in the above-mentioned production examples and comparative production examples, the presence or absence of Cl group is first checked for the product, and CI!
For those in which the presence of groups is recognized, we quantify them.
Its abundance was expressed in millimole equivalents per 1000 grams of product.

In addition, regarding the obtained product, 5i-3i with a long chain structure
V
1! Approved. Furthermore, in conjunction with this, the presence or absence of bonding of substituents in the side chains was confirmed by examining FT-IR and/or protons in the substituents by FT-NMR.

The structure of the synthesized product was determined from the results obtained above.

The above-mentioned confirmation of the presence or absence of CX groups in the product is carried out using a fluorescent X-ray analyzer (fully automated fluorescent X-ray analyzer system 3080).
: manufactured by Rigaku Denki Kogyo Co., Ltd.). At that time, trimethylylolsilane (manufactured by Chinso Co., Ltd.) was prepared as a standard sample, and it was mixed with 1.5, 10, 50.100
Standard solutions were prepared by diluting each diluted twice, and each standard solution was applied to the fluorescent X-ray analyzer to measure the amount of Cβ groups, and a calibration curve was determined based on the obtained results. On the other hand, regarding the product to be tested, 1 gram of it was dissolved in dehydrated toluene and the total amount was 10 mJ! A test sample is prepared as follows, and it is measured by applying it to the fluorescence XvA analyzer,
The measurement results were compared with the above inspection line to determine the amount of CZ groups.

For measurement by FT-I H, a KBr pellet of the test sample is prepared, and this is subjected to N1colet FT-I R.
750 (manufactured by Collet Japan). In addition, measurement by FT-NMR is
The test sample was dissolved in CD (1!), and this was analyzed by FT-NMR.
The measurement was carried out by using an FX-9Q (manufactured by JEOL Ltd.).

In addition, in the UV spectrum, if the polysilane compound is a low-molecular one, the spectrum will be on the short wavelength side, and if it is a polymer, the spectrum will be on the long wavelength side. Chemistry (Pure & Applied Chemistry)
5↓, N15. pp.

1041-1050 (1982).

1J0- A Mitsuro flask was prepared in a blow box that had been vacuum suctioned and replaced with argon, a reflux condenser, a temperature needle, and a dropping funnel were attached to it, and argon gas was passed through the bypass pipe of the dropping funnel.

100 grams of dehydrated dodecane and 0.3 mol of wire-shaped sodium metal were placed in this Mitsuro flask, and 0.1 mol of zero-order dichlorosilane monomer (Nisso side type) (a-7) heated to 100°C with stirring was added. Dehydrated dodecane 3
The prepared solution was slowly added dropwise to the reaction system.

After the dropwise addition, a white solid was precipitated by linear polymerization at 100° C. for 1 hour. Thereafter, the mixture was cooled, the dodecane was decanized, and 100 g of dehydrated toluene was added to melt the white solid, and 0.01 mol of sodium metal was added.

Next, n-hexyl chloride (manufactured by Tokyo Kasei) (b3)
A solution prepared by dissolving 0.01 mol in 10 ml of toluene was slowly added dropwise to the reaction system while stirring,
It was heated at 100°C for 1 hour. Thereafter, the mixture was cooled, and 50 mA of methanol was slowly added dropwise to remove excess metal sodium. This produced a suspended layer and a toluene layer.

Next, the toluene layer was separated, concentrated under reduced pressure, and purified by developing with a silica gel column and chromatography.
The product was obtained in a yield of . For this product, the C
When measured using the method for measuring Z group content, no CZ group was found to be present (ie, 0.00 mmole equivalent in 1000 grams of sample).

In addition, the weight average molecular weight of this product was determined by GPC method.
When measured by HF development, it was 75,000 (
(using polystyrene as a standard), the product was subjected to FT-IR measurement using the method described above, and then FT-N
MR measurement revealed that it was 5i-Cj! bond, 5i-0-3
! It was found that there was no bond, 5i-0-R bond, and that the product was a polysilane compound having the above-mentioned structure of C-1.

The above results are shown in Table 4.

Appropriate Amount I A three-way flask was prepared in a blow box that had been vacuum-suctioned and replaced with argon, and a reflux condenser, temperature needle, and dropping funnel were attached to it, and argon gas was passed through the bypass pipe of the dropping funnel.

In this Mitsuro flask, 100 grams of dehydrated dodecane and 1
Prepared by dissolving 0.1 mole of 0-order dichlorosilane monomer (manufactured by Chisso) (a-7) in 30 g of dehydrated dodecane, which was charged with 0.3 mole of n-square metallic lithium and heated to 100°C while stirring. The solution was slowly added dropwise to the reaction system. After the dropwise addition, a white solid was precipitated by line polymerization at 100° C. for 2 hours. After this time it was cooled, the dodecane was decanted and an additional 100 grams of dehydrated toluene was added to dissolve the white solid and 0.02 mole of metallic lithium was added.

Next, chlorobenzene (manufactured by Tokyo Kasei), (b-5) 0.
A solution prepared by dissolving 02 mol in 10 ml of toluene was slowly added dropwise to the reaction system with stirring, and 1
Heated at 00°C for 1 hour. Thereafter, the mixture was cooled, and 50 ml of methanol was slowly added dropwise to remove excess metal lithium. This produced a suspended layer and a toluene layer.

Next, the toluene layer was separated, concentrated under reduced pressure, and purified by development using a silica gel column and chromatography to obtain polysilane compound 2 (structural formula: C-3). Yield is 7
2%, and the weight average molecular weight was 92,000.

The results are shown in Table 4.

Production Twist 1 A three-way flask was prepared in a blow box that had been vacuum-suctioned and replaced with argon, a reflux condenser, a temperature needle, and a dropping funnel were attached to it, and argon gas was passed through the bypass pipe of the dropping funnel.

100 grams of dehydrated n-hexane and 0.3 mole of metal sodium of 1 square inch were charged into this Mitsuro flask, and heated to 80°C with stirring. Zero-order dichlorosilane monomer (Chisso IJ) (a-7) A solution prepared by dissolving 0.1 mol in dehydrated n-hexane was slowly dropped into the reaction system. After 0 dropwise addition, condensation polymerization was carried out at 80° C. for 3 hours to precipitate a white solid. Thereafter, it was cooled, n-hexane was decanted, and 100% of dehydrated toluene was added.
The white solid was dissolved by adding 0.01 mol of sodium metal, and then 0.01 mol of benzyl chloride (manufactured by Tokyo Kasei) (b-12) was added to 10 mj of toluene! A prepared solution was slowly added dropwise to the reaction system with stirring, and the mixture was heated at 80° C. for 1 hour. Thereafter, the mixture was cooled, and 50 mff1 of methanol was slowly added dropwise to remove excess metal sodium. This produced a suspended layer and a toluene layer.

Next, the toluene layer was separated, concentrated under reduced pressure, and purified by development using a silica gel column and chromatography to obtain polysilane compound m3 (F!Ij formula 2c-4). The yield was 61% and the weight average molecular weight was 47,000. The results are shown in Table 4. In this polysilane compound, unreacted 5i-Cj! , by-product S i
-0-3t, there was no TR absorption assigned to S 1-O-R.

Synthesis was carried out in the same manner as in Example 3 using the dichlorosilane monomer and end group treatment agent shown in Table 1, and polysilane compound magnetodynamic 4 (structural formula: C-6) and polysilane were synthesized in the same manner as in Example 3. Compound 5 (
Structural formula: C-2) were obtained in yields of 60% and 62%, respectively. In addition, in this polysilane compound, unreacted 5t-Cj! , by-product Si-○-3i, 5t-0
There was no TR absorption attributed to -H. The identification results are summarized in Table 4.

Synthesis was carried out in the same manner as in Example 3, except that dichlorosilane monomer (manufactured by Chisso) (a-7) was condensed in the same manner as in Example 3, and the end groups of the polymer were not treated. A polysilane compound NID-1 having the structural formula shown in Table 4 was obtained. The yield was 60% and the weight average molecular weight was 46,000. The results are shown in Table 4.

In addition, in this polysilane compound, TR absorption attributed to unreacted S 1-CI and by-product 5t-OR was observed in the terminal group.

Polymerization was carried out in the same manner as in Example 3, using the dichlorosilane monomer shown in Table 2 and changing the reaction time as shown in Table 2. Further, a synthetic product using the compounds shown in Table 2 as the end group treatment agent was purified in the same manner as in Production Example 3. Thus, the polysilane compounds Na6~ shown in Table 4
Got 10.

The yield and weight average molecular weight of each polysilane compound obtained were as shown in Table 4.

In addition, in any polysilane compound, unreacted 5
t-C1, by-product 5i-0-3t.

There was no TR absorption assigned to 5i-0-R.

Polysilane compound Arashi D-2 shown in Table 4 was synthesized in the same manner as in Production Example 6 except that the reaction time of the dichlorosilane monomer was changed to 10 minutes.

The yield and weight average molecular weight of the polysilane compound obtained were as shown in Table 4.

Note that the obtained polysilane compound contains unreacted (7)
Si-C(1, by-product (D S i -0-S i
.

There was no IR absorption assigned to 5i-0-R.

Synthesis was carried out in the same manner as in Example 1 using the dichlorosilane monomer and end group treatment agent shown in Table 3 to obtain polysilane compounds 1 ml to 14 shown in Table 4. The yield and weight average molecular weight of each polysilane compound obtained were as shown in Table 4.

A Mitsuro flask was prepared in a blow box that had undergone vacuum suction and argon replacement, and a reflux condenser, thermometer, and dropping funnel were attached to it, and argon gas was passed through the bypass pipe of the dropping funnel. .

100 grams of dehydrated dodecane and 0.3 mol of wire-like sodium metal were placed in this Mitsurofask, and 0.1 mol of zero-order dichlorosilane monomer (manufactured by Chisso) heated to 100°C with stirring was added to 30 grams of dehydrated dodecane. By slowly dropping a solution prepared by dissolving it into the reaction system, after 0 drops, condensation polymerization was carried out at 100 ° C. for 1 hour.
A white solid precipitated out. After this, it is cooled and methanol is used at 50 mA to treat excess metal sodium! was slowly dripped.

Next, the white solid was filtered and washed repeatedly with n-hexane and methanol.
Got 3.

This polysilane compound contains toluene, chloroform, TH
F etc. were insoluble in the organic solvent. The results were as shown in Table 4.

Prepare a Mitsuro flask in a blow box that has been vacuum-suctioned and replaced with argon.A reflux condenser, thermometer, and dropping funnel are attached to it, and argon gas is passed through the bypass pipe of the dropping funnel. did.

100 grams of dehydrated dodecane and 0.3 mole of wire-shaped sodium metal were placed in this Mitsuroh flask and heated to 100° C. with stirring.

Next, diphenyldichlorosilane monomer (manufactured by Chisso Department)
A solution prepared by dissolving 0.1 mole of in 30 grams of dehydrated dodecane was slowly added dropwise to the reaction system.
A white solid was precipitated by condensation polymerization at 0° C. for 1 hour.

After this, it is cooled and the excess metal sodium is disposed of.
Methanol 50mj! was slowly dripped.

Next, the white solid was filtered, washed repeatedly with n-hexane and methanol, and the polysilane compound Arashi D-
I got 4.

This polysilane compound contains toluene, chloroform, TH
It was insoluble in organic solvents such as F. The results are shown in Table 4.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

A stainless steel plate with mirror polishing on the surface (made of SUS304, area 50fl x 50mm, thickness 0
．． 5 Dragon) was used.

Silver was deposited on the upper surface of the support 101 to an average layer thickness of 1 μm using an argon spunter. Regarding the surface properties of the silver, by setting the substrate temperature at about 350° C. during silver deposition, the surface was made uneven with a surface roughness of about 0.5 μm and an average distance between protrusions of about 1 μm. In this way, the reflective conductive layer 102 was formed.

The polysilane layer was deposited to a thickness of 0.8 μm using the polysilane shown in Production Example 1 by a spinner method.

When the surface of the obtained polysilane layer 103 was observed using an electron microscope, a uniform uneven structure was observed over the entire area of the substrate, with a roughness of about 0.8 μm and an average distance between protrusions of about 1.0 μm. This was confirmed.

Using the substrate prepared by the above method, 16 amorphous silicon solar cells having the layer structure shown in FIG. 1 and each having an area of 1 d as shown in FIG. 3 were fabricated. The output characteristics of these amorphous silicon solar cells under a standard light source (AMl, 5.100 mW/cd) were evaluated, and the results are shown in Table 5. Conversion efficiency, short-circuit current, open circuit voltage, and fill factor were calculated by calculating average values excluding those solar cells on the substrate that were clearly leaking. The obtained value was normalized as 1.

[Comparative example]

As a comparative example to the embodiment of the present invention, an average thickness of 1μ
m silver with a mirror surface (S) and an average distance between convex parts of about 1
A stainless steel substrate was deposited to form an uneven surface (T) with a roughness of approximately 0.5 μm, and ZnO was deposited on the (T) substrate to a thickness of approximately 0.8 μm using a sputtering apparatus shown in FIG. The same solar cells as in Example 1 were prepared using three types of substrates (Z) deposited on the substrate, and the output characteristics were evaluated.The results are shown in Table 6. In addition, each characteristic value is normalized by the value obtained by the solar cell of Comparative Example (S).

Solar cell of Example 1 (P) and solar cell of Comparative example (T)
, (Z) was repeated 10 times and the conversion efficiency of solar cells (P), (T), and (Z) was investigated. The results are shown in Figure 4. Figure 5 shows the percentage of solar cells that do not survive (hereinafter referred to as ``survival rate''). Especially for solar cells (T), the variation in output characteristics between each loft is large and the survival rate is also quite small. This is thought to be because peeling between the silver layer and the amorphous silicon layer and leakage at the convex parts of the uneven structure are likely to occur.In the solar cell (P), such parts are covered with a polysilane compound. Therefore, it is thought that peeling is difficult and leakage is unlikely to occur (and even if leakage occurs, its influence is unlikely to be seen due to the moderate resistivity of the polysilane layer).

Fork support 1 As the base material of the support 101, an aluminum plate (area 50 m x 50 tm, thickness 0
．． In this example, this support 1
01 also serves as a reflective conductive layer, and a polysilane layer 103 is formed thereon.

The polysilane compound shown in Production Example 2 was used for the polysilane layer. The polysilane layer 103 was formed by dissolving the polysilane compound in toluene and using a spinner method.

After uniformly applying polysilane using a spinner with a rotation speed of 1000, the rotating table of the spinner was rotated at 100 Hz and an amplitude of 0.1.
It was vibrated at 100 mm to form irregularities of polysilane. Furthermore, the substrate on which the polysilane layer has been formed is placed in a vacuum container,
A mixed with 11000pp of A3F & gas 10
It was dried with a flow of 0 sccya.

When the surface of the substrate 104 thus obtained was observed using an electronic gJ mirror, a uniform uneven structure was observed over the entire area of the substrate, with a roughness of 0.6 μm and an average pitch of about 1.5 μm. It was confirmed that it was 0 μm.

An amorphous silicon solar cell similar to that in Example 1 was produced using the substrate produced by the above method. Table 7 shows the results of evaluating the output characteristics of this solar cell.

In this embodiment, an aluminum plate (area: 50 m x 50 m, thickness: 0.5 m) with a mirror-polished surface was used as the base material of the main support 101. Silver with a thickness of approximately 1 μm and having a mirror surface was deposited as layer 102 by sputtering. On top of this is a polysilane layer 10.
3 was formed.

In this example, the polysilane compound synthesized in Production Example 3 was used.

The polysilane compound was dissolved in xylene, and TPA was added to 0.
1% was added.

The polysilane compound thus obtained was applied by a spray method. After that, the substrate was 1001(z.

It was vibrated with an amplitude of 0.1 fl to create an uneven structure.

When the surface of the substrate 104 obtained in this manner was observed using an electron microscope, a uniform uneven structure was observed over the entire area of the substrate, with a roughness of 0.6 μm and an average distance between protrusions of approximately 0.9 μm. It was confirmed that

An amorphous silicon solar cell similar to that in Example 1 was produced using the substrate produced by the above method. Table 8 shows the results of evaluating the output characteristics of this solar cell.

As the base material for the main support body 101, stainless steel (SUS304) with a mirror-polished surface is used (area: 50 mm x 501 irises,
In this example, this support 1
Approximately 1μ with specular surface as reflective conductive N102 on 01
Roots with a thickness of m were deposited by the Suba-7ta method. A polysilane layer 103 was formed on this.

The polysilane compound shown in Production Example 4 was used in this example. The polysilane compound was dissolved in xylene and applied using a spinner method. The irregularities on the surface of the polysilane layer were formed by applying a polysilane compound with a spinner and then vibrating the rotary table of the spinner. The conditions for vibration were as shown in Table 5. The surface roughness of the polysilane layer was as shown in Table 5. Further, a solar cell was formed on such a surface substrate in the same manner as in Example 1.

The conversion efficiency of the solar cells was as shown in Table 9.

(Leaving space below) Table 5 Table 5 [Summary of the effects of the invention] As described above, according to the present invention, the uneven surface has a light confinement effect. At the same time, it prevents penetration of metal atoms etc. into the amorphous silicon layer, prevents leakage of solar cells due to the uneven structure, and minimizes the negative effects even if leakage occurs. As a result, it is possible to fabricate a solar cell substrate that makes the output characteristics of the solar cell stable and excellent by a simple method.

[Brief explanation of drawings]

FIG. 1 is a schematic structural diagram of a solar cell using the improved solar cell substrate according to the present invention. FIG. 2 is a schematic structural diagram of a spuck apparatus for producing an improved solar cell substrate according to the present invention. FIG. 3 is a block diagram of each unit cell of a solar cell manufactured using the improved solar cell substrate according to the present invention. FIG. 4 shows solar cells (P) in Example 1 and Comparative Example;
It is a graph showing the transition of conversion efficiency when the comparative experiment of (T) and (Z) is repeated 10 times. FIG. 5 shows solar cells (P) in Example 1 and Comparative Example;
It is a graph showing the transition of survival rate when the comparative experiment of (T) and (Z) was repeated 10 times. 101...Base, 102...Reflective conductive layer, 103
...Polysilane layer, 104...Substrate, 105...
N-type amorphous silicon layer, 106... I-type amorphous silicon layer, 107... P-type amorphous silicon layer, 10B... PIN-type amorphous silicon solar cell, 109... Transparent conductive film, 110... Collection Electrode, 201... Chamber 202... Anode electrode with base holder, 203.
...Cathode 1 with target holder! pole, 204・
... Insulator, 205 ... Matching box, 206
...RF power supply, 207...Shutter 208...
Substrate, 209... Sputtering target, 210...
・Ar gas introduction pipe for sputtering, 211...exhaust hole, 2
12... Substrate heating heater 301... Substrate, 30
2... Unit solar cell, 303... Transparent conductive film, 304... Current collecting electrode.

Claims (2)

[Claims] (1) It has an uneven surface of 0.1 μm or more on the conductive support, is represented by the general formula [I], and has a weight average molecular weight of 60
1. A solar cell substrate comprising a layer composed of a novel and hitherto unknown polysilane compound having a molecular weight of 00 to 200,000. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] (However, in the formula, R_1 is an alkyl group with 1 or 2 carbon atoms,
R_2 represents an alkyl group having 3 to 8 carbon atoms, a cycloalkyl group, an aryl group, or an aralkyl group, R_3 represents an alkyl group having 1 to 4 carbon atoms, and R_4 represents an alkyl group having 1 to 4 carbon atoms. A and A' are each an alkyl group, cycloalkyl group, aryl group or aralkyl group having 4 to 12 carbon atoms, and they may be the same or different. n and m are molar ratios indicating the proportion of each monomer number to the total monomers in the polymer, n+m=1, 0<n≦1, 0≦m<1. ) (2) A claim in which A and A' in general formula [I] are an alkyl group or a cycloalkyl group having 5 to 12 carbon atoms (
1) The solar cell substrate according to item 1).