JPH04199686A - photovoltaic element - 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 relates to an MIS junction type photovoltaic device using a novel polysilane compound as an organic semiconductor layer. The present invention relates to a photovoltaic device in which a refractive index adjusting agent is distributed in an organic semiconductor layer consisting of the following.

[Prior art] Conventionally, photovoltaic devices using organic semiconductors have very low collection efficiency and low photoelectric conversion efficiency, so pn junction type and pin junction type photovoltaic devices using crystalline silicon or amorphous silicon have been developed. The current situation is that research for practical application is lagging behind research.

However, since thin films can be easily formed, it is expected that production costs will be reduced, and various studies have been conducted on organic semiconductors with the aim of improving photoelectric conversion efficiency.

Organic semiconductor materials suitable for photovoltaic devices include anthracene, tetracene, merocyanine, phthalocyanine, hydroxyne squarylium, chlorophyll, and virol, among which merocyanine, phthalocyanine, hydroxyne squaryllium, etc. are suitable for photovoltaic devices. Using a dye designed and developed as a material, the photoelectric conversion efficiency of the Schottky barrier cell is approximately 0.000% under AMO spectrum light.
It is about 2 to 1%. [Jpn J, Appl, P
hys,,20゜5upp1.20-2.135(19
801, Appl, Phys, I-ctt, , 32.
495f+9781, J, Chew, Phys-,
71, 1211f19791] What is the reason for such a low photoelectric conversion rate?

The main reason is that the carrier trap density in organic semiconductors is large, and both the carrier lifetime and mobility are small.
This is thought to be due to the short diffusion length.

Furthermore, since organic semiconductors generally have a high resistivity, it is difficult to form ohmic contacts, and furthermore, it has been pointed out that there are problems such as a decrease in photoelectric conversion efficiency as the intensity of incident light increases.

On the other hand, polysilane compounds having silicon as a main skeleton are attracting attention as materials to replace the above-mentioned conventional organic semiconductor materials having carbon as main skeleton.

In the old days, polysilane was reported to be insoluble in solvents [The Journal of the American Chemical Society; 125.2291pp (1924)]
Recently, it has been reported that polysilane is soluble in solvents and can be easily formed into films [The Journal of the American Ceramic Society: Rainbow, 50
4 pp (197811) It began to attract attention.

Furthermore, since polysilane photodecomposes when irradiated with ultraviolet rays, research has been reported to apply it to resists [Unexamined Japanese Patent Application Publication No. 1989-1999-
No. 98431, Japanese Patent Application Laid-open No. 119550/1982]
.

In addition, polysilane has the property of a photosemiconductor in which charge can be transferred through the 〇-bonds in the main chain, and it is expected to be applied to electrophotographic photoreceptors [Physical Review B: 35.2818 pp (19871)] However, for application to such electronic materials, polysilane compounds must not only be soluble in solvents and have film-forming ability, but also be capable of forming films without minute defects and with high homogeneity. Since minute defects cannot be tolerated in electronic materials, there is a need for high-quality polysilane compounds that have a clear structure with regard to II substituents and do not cause abnormalities in film formation.

Although various synthetic research examples regarding polysilane compounds have been reported, there are still problems in using them as electronic materials. In low molecular weight polysilane compounds, all Si
Structures in which the base is substituted with an organic group have been reported [Journal of A+Werican Ch.
94. (111
3806pp+197211, Special Publication Showa 63-3803
Publication No. 3].

The structure described in the former publication has a structure in which the terminal group of dimethylsilane is substituted with a methyl group, and the structure described in the latter publication has a structure in which the terminal group of dimethylsilane is substituted with an alkoxy group. Both have a degree of polymerization of 2 to 6 and do not exhibit the characteristics of polymers. In other words, due to their low molecular weight, they do not have film-forming ability as they are, making them difficult to use industrially.
A high-molecular-weight polysilane compound with a structure in which all Si groups are substituted with organic groups has recently been reported [Nikkei New Materials, August 15 issue, page 46, 119881], but because it goes through a special reaction intermediate, Industrial mass production is difficult because a decrease in synthesis yield is expected.

In addition, the method for synthesizing polysilane compounds is described in [The Journal Saibu Sairuganometallic Chemistry + 198
pp, C27, f191101 or The Journal of Polymer Science, Polymer Chemistry.
Edition: Vol, 22.159-170ppf1
Reported by 98411. However, all of the reported synthesis methods involve only the condensation reaction of the polysilane main chain, and there is no mention of the terminal groups, and in all of the synthesis methods, unreacted chlorine groups and byproducts are generated due to side reactions. Therefore, it is difficult to consistently obtain the desired polysilane compound.

Examples of using the above-mentioned polysilane compounds as photoconductors have also been reported (U, S, P, No. 4618551
, U, S, P, No. 4772525, JP-A-62-2
69964), the influence of unreacted chloro groups and by-products due to side reactions is presumed.

In U, S, P, No. 4618551, the polysilane compound described above is used as an electrophotographic photoreceptor, but an unusually high applied potential of 1000 V is used, whereas in a general copying machine, the applied potential is only 500 to 800 V. ing. This is thought to be because, at a normal potential, structural defects in polysilane cause defects in the electrophotographic photoreceptor, causing spots-like abnormal phenomena on one image to disappear. Also, JP-A-62-26996
In Publication No. 4, an electrophotographic photoreceptor was prepared using the above-mentioned polysilane compound and its photosensitivity was measured, but the photosensitivity was slow and there was no advantage compared to conventionally known selenium photoreceptors or organic photoreceptors. I don't have either.

In order to be used in such electronic materials, there are still many problems, and the reality is that polysilane compounds that can be used industrially have not yet been provided. No study has been made regarding its application to electromotive force elements.

[Problems to be Solved by the Invention] An object of the present invention is to solve the problems of the prior art described above, and to provide a method that is inexpensive, uniform over a large area, and has high photoelectric conversion efficiency.
An object of the present invention is to provide a photovoltaic device using an organic semiconductor.

Another object of the present invention is to provide a photovoltaic device using, as a semiconductor layer, a novel polysilane compound whose properties are significantly improved over conventional organic semiconductors.

Furthermore, another object of the present invention is to control changes in incident light intensity and
An object of the present invention is to provide a photovoltaic element that is stable against changes over time.

Another object of the present invention is to increase the amount of light incident on the photovoltaic element and improve the photoelectric conversion efficiency.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present inventors have made extensive research and found that a linear polysilane compound represented by the following general formula (I) He discovered that the characteristics were dramatically improved compared to semiconductors, and completed research to make it fully operational and functional as a photovoltaic device. What is the gist of it?

(1) General formula (I) (However, in formula 1, 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, R1 is an alkyl group having 1 to 4 carbon atoms, R4 is an alkyl group having 1 to 4 carbon atoms, A and A' are an alkyl group having 4 to 12 carbon atoms, and a cycloalkyl group, respectively. , an aryl group or an aralkyl group, 1 may be the same or different, n and m are molar ratios indicating the proportion of the number of each monomer to the total monomers in the polymer, n + m = 1
Therefore, 0<n≦1.0≦m<1. ) and has a weight average molecular weight of 6,000 to 200,000 as an organic semiconductor layer, and a refractive index adjuster is distributed along the thickness direction of the organic semiconductor layer to produce an MIS junction photovoltaic element. 12)-8 In the polysilane compound represented by formula (I), A and Ao are an alkyl group having 5 to 12 carbon atoms or a cycloalkyl group; and (3) in the organic semiconductor layer. This includes that the refractive index gradually increases along the direction of light emission.

The present invention will be explained in detail below.6 The novel polysilane compound represented by the general formula (1) and having a weight average molecular weight of 6,000 to 200,000, provided by the present invention, has no chlorine group or side reaction forming group. All Si groups are substituted with specific organic groups that do not contain oxygen, are non-toxic, and are free from toluene, benzene,
It is easily soluble in aromatic solvents such as xylene, halogenated solvents such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, and other solvents such as tetrahydrofuran (THF) and dioxane, and has excellent film-forming ability. The film formed using the polysilane compound of the present invention is homogeneous and has a uniform thickness, has excellent heat resistance, is rich in hardness, and has a toughness of 1.
ss).

For these reasons, the polysilane compound provided by the present invention is a polymeric substance that can be used in the production of electronic devices, especially photovoltaic elements, and has high industrial utility value.

As mentioned above, the novel polysilane compound represented by the general formula (I) provided by the present invention has a weight average molecular weight of 6,000 to 200,000, but has poor solubility in solvents and film-forming ability. More preferable from this point of view are those having a weight average molecular weight of 8000 to 1200.
00, and the optimal one has a weight average molecular weight of 10
000 to 80,000.

Regarding the weight average molecular weight, 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, while those with a weight average molecular weight of 200,000 or more have poor solubility in solvents and cannot be used to form the desired film. Difficult to form.

Moreover, when the above-mentioned polysilane compound represented by the general formula (1) of the present invention is desired to have particularly strong toughness in the film to be formed, the terminal groups A and A are used.

is an alkyl group having 5 to 12 carbon atoms, and an alkyl group having 5 to 12 carbon atoms.
In this case, the most preferred polysilane compound of the present invention is a group in which the terminal groups A and Ao are alkyl groups having 5 to 2 carbon atoms. This is the case when the group is selected from a group and a cycloalkyl group having 5 to 12 carbon atoms.

The above-mentioned novel polysilane compounds provided by the present invention can be generally synthesized in a similar manner. That is, in a high-purity inert atmosphere free of # elements and water, 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.

The obtained polymer is separated from unreacted polymers, and the polymer is reacted with a predetermined halogenated organic reagent in the presence of a condensation catalyst made of an alkali metal to form an organic group at the end of the polymer. Synthesized by condensation.

In the above synthesis operation, the starting material dichlorosilane, the intermediate polymer, the halogenated organic reagent, and the alkali metal condensation catalyst all have high reactivity with oxygen and moisture, so these oxygen and moisture (r Under such an atmosphere, the above-mentioned polysilane compound which is the object of the present invention cannot be obtained.

Therefore, the above-mentioned operation for obtaining the polysilane compound of 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 ensure that neither oxygen nor moisture is present 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.

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 above halogenation is used to introduce a specific organic group! The reagents and the above-mentioned solvents used are also deoxidized in the same manner as the dichlorosilane monomer before being introduced into the reaction system. Note that the solvent is dehydrated by distilling under reduced pressure using the deoxidized argon gas described above, and then further dehydrating with metallic sodium.

The above condensation catalyst is used in the form of wires or chips, and this operation is carried out in an anhydrous paraffinic solvent or in an inert gas atmosphere such as Ar or N2 to prevent oxidation.

The dichlorosilane monomer used as a starting material for producing the novel polysilane compound represented by the general formula (1) of the present invention is a silane compound represented by the following formula: R, R, 5iC1, or a silane compound represented by the following formula: R, R, 5iC1. General formula: R, R, 5
Silane compounds represented by iC1, are selectively used.

The above-mentioned condensation catalyst is preferably an alkali metal that causes a condensation reaction by eliminating halogen, 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 a substituent represented by A and 8, 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, namely the general formula:
A-X and/or general formula: A'-x (However, X is C
I or Kano), and appropriate compounds among the specific examples described below are selectively used.

One-shot formula used in synthesizing the above-mentioned intermediate polymer: RIR2SiC1z or this and general formula 2J (, r
The dichlorosilane monomer represented by l, 5icI□ is
It is dissolved in a predetermined solvent and introduced into the reaction system.

As the solvent, a paraffinic non-polar hydrocarbon solvent is preferably used. Preferred examples of the solvent include:
Mention may be made of n-hexadi, 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 monomer.1 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.

A desirable embodiment of the method for producing the novel polysilane compound represented by the general formula (1) of the present invention described above will be described below.

That is, the method for producing the above-mentioned novel polysilane compound according to the present invention includes the steps of producing (it intermediate polymer) and (11)
) of introducing substituents A and A' into the terminals of the intermediate polymer.

The above step (i+) 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 anhydrous paraffinic solvent and an anhydrous condensation catalyst, then add an anhydrous dichlorosilane monomer, and heat the whole to a predetermined temperature while stirring to condense the monomers. 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 by the reaction formula fil below, the chloro group of the dichlorosilane monomer and the catalyst undergo a desalting reaction, and the Si groups are repeatedly condensed to form a polymer, thereby producing an intermediate polymer.

In the specific reaction procedure, a condensation catalyst (alkali metal) is placed in a paraffinic solvent, and dichlorosilane monomer is added dropwise while stirring under heating.

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

R, R4 R,R.

(However, A=A' may also be used.) Specifically, in this step, an aromatic solvent is added to the intermediate polymer obtained by condensation of dichlorosilane monomer to dissolve it.8 Next, a condensation catalyst (alkali metal) is added. , add the halogenated organic agent dropwise at room temperature. At this time, in order to compete with the condensation reaction between the polymer end groups, a halogenated organic agent is added in an equivalent amount to the starting 1,000 ml. Add an excess of ~0.1 equivalents. Gradually heat and stir at 80°C to 100°C for 1 hour to carry out the desired reaction.

After the reaction is cooled, methanol is added to remove the alkali metal of the catalyst. Next, the polysilane is extracted with toluene and purified using a silica gel column.

Thus, the desired new polysilane compound of the present invention is obtained.

The dichlorosilane monomer and the halogenated organic agent will be specifically illustrated below.

R1 mouth 2 SiCI2 and RJ < 5iC1z tool side note)
:Among the following compounds, a-2-16,18,20,
21°23.24 is used for RIRZSICI2, a
-1, 2, 11, 1? , 19.22.23.25 is used for lJ, 5iclx.

[CI+112SiC12a-1 flcll, 1. (:H125iCI2 a
-22(IcH-1-C1z 5iC1t
-Example of a-25A-X UA'-X (CH,l,ClIC1,C1b-1cut +CI
1.14C1b-2 C113 (Ctlil scI
b-3CH, (CH,l,.C1b-4 C11,-(I>-C1b-6 @clb-7 co, ()clb-11 C11,0@-CJ b-9MC'
b-1゜◇XC112C1b-12 (□(cu, l IC1bi3 cL (C1lxl sBr b
-14C11-(CHxl 1゜Br
b-15 again. Specific examples of the polysilane obtained are shown below.

CI+.

director C1(3 C1+.

■ CI+.

CI+.

C.I.

CH.

C.I.

CH.

CHs lcl+21 s -FSl b-fcLl
5CH3CH (CH Yul, c-18
CI (C)l-)tCH(CHsl-c-20 CH1 CHICIl,l.

C1(.

C1, CL CIL, CIL CIl, CHs C](3 ■ CIl.

C11゜ CIl.

Note) In the above structural formula, both X and Y represent monomer polymer units, and n is X/ (X+Y).

Further, m is determined by the formula Y/(X+Y).

In the present invention, a photovoltaic device is constructed using the above novel polysilane compound as an organic semiconductor layer, and the structure of the photovoltaic device of the present invention will be explained below.

The photovoltaic device of the present invention is M r S ILleLa
l In5u-tator 5esicandduct
By forming the rl junction, the minority carriers generated in the polysilane semiconductor layer can be utilized for the i effect to obtain a high open circuit voltage.

Furthermore, since the polysilane compound used in the photovoltaic device of the present invention has relatively high sensitivity to short wavelength light,
Compared to conventional photovoltaic devices using organic semiconductors, it is possible to obtain a higher open circuit voltage and significantly improve photoelectric conversion efficiency.

The polysilane compound used in the photovoltaic device of the present invention is easily soluble in many types of solvents and has excellent film-forming ability, so that it can be uniformly formed over a large area.
It has excellent adhesion to the support and excellent uniformity of properties.

Therefore, it can be suitably used as a photovoltaic element for a solar cell that requires a large area for electric power.

The polysilane compound used in the present invention has a stable molecular structure, so it has excellent property stability, and the change in photoelectric conversion efficiency over time is dramatically smaller than that of conventional photovoltaic devices using organic semiconductors. Furthermore, the photoelectric conversion efficiency is significantly improved compared to conventional photovoltaic devices using organic semiconductors.

Furthermore, the phenomenon of a decrease in photoelectric conversion efficiency due to an increase in the amount of incident light has been significantly improved. Furthermore, it has excellent heat resistance, and stable output characteristics can be obtained even under conditions of severe temperature changes.

The light absorption properties of the polysilane compound used in the present invention can be arbitrarily changed by changing the molecular weight distribution or the substituents on its side chains, making it possible to design a photovoltaic device suited to the usage environment.

In the photovoltaic device of the present invention, since light is incident from the metal layer side, it is necessary to suppress absorption of light in the metal layer and the insulating layer as much as possible. Furthermore, in a metal layer, the barrier height is due to the work function of the metal, and in an insulating layer, the barrier height and minority carrier tunnel Fl are
Since the magnitude of the l ratio greatly controls the collection efficiency, it is necessary to appropriately select the constituent material and film thickness of each layer.

Examples of the layer structure of the photovoltaic device of the present invention are shown below, but the photovoltaic device of the present invention is not limited thereby.

FIGS. 1(A) and 1(B) are diagrams schematically showing a typical example of a layer structure when a polysilane semiconductor film according to the present invention is used as a photovoltaic element according to the present invention.

FIG. 1 (shown in A+'1-Example is a polysilane semiconductor layer +03.Insulating layer I in which a lower electrode 102 and a refractive index adjusting agent are distributed along the thickness direction of a semiconductor layer 103 on a support 101.
04. Photovoltaic element 10 in which metal layer 1051 anti-'14 prevention 110106 and current collecting electrode 107 are deposited in this order
It is 0. Note that in a single photovoltaic element, light is incident from the metal layer 105 side.

In the example shown in FIG. 1 (13), a current collecting electrode +07 is placed on a transparent support +01, an antireflection film 106. Metal layer +05, insulating layer 104. Polysilane semiconductor layer +03. in which a refractive index adjusting agent is distributed along the thickness direction of the semiconductor layer 103. This is the photovoltaic device 100 in which the lower electrode 102 is deposited in this order. In addition, in this photovoltaic element, the person of light Q-1 is performed from the side of the transparent support 101.

The configurations of these photovoltaic elements will be explained in detail below.

Polysilane semiconductor layer 10 in the photovoltaic device of the present invention
Examples of polysilane compounds suitably used for No. 3 include the novel polysilane compounds c-1 to C-43 described above.

These polysilane compounds not only have good semiconductor properties but also excellent moldability.

Examples of the method for forming a film on the support include a coating method, a spin coating method, a dipping method, an electrodeposition method, and a sublimation vapor deposition method, which are appropriately selected depending on the shape of the support used and the like. In each film forming method, the refractive index adjusting agent is distributed and dispersed in the polysilane semiconductor layer using the refractive index adjusting agent dispersion method described later.

The thickness of the polysilane semiconductor layer in which the refractive index adjusting agent is dispersed is preferably 1nWl to 5XIO'nm, more preferably 5nm to lx106nm, optimally, in order to form an MIS junction and obtain sufficient photoelectric conversion efficiency. ION
It is preferable that the range is from m to 5XIO'nm.

The refractive index adjusting agent used in the present invention is dispersed in the organic semiconductor layer formed from the polysilane compound with a desired concentration distribution along the film thickness direction. The material of the refractive index adjusting agent may be an inorganic compound, a metal, or an organic compound, which can be uniformly dispersed in the polysilane compound and does not impair the properties of the polysilane compound as an organic semiconductor. Select.

Specifically, the refractive index adjusting agent includes CaFt and LiF.

Mg mouth, 5iOz, AIzOz, CaCO5, MgFi
, Ti0t, Fe20x, Ce0z-*Ot, NaF,
Inorganic compounds such as CdS, ZnS, BizOx, Be.

Mg, a, Sr, a, La, Cri, Cr, Mn,
Ni, Cu, Ag, Au, ^1. Metals such as Sb, ebonite 1. Amber, tartaric acid, sucrose, paraffin, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, silicone resin, nylon, polyethylene, polyester,
Examples include organic compounds and synthetic resins such as polystyrene, methyl meccrylate resin, and melamine resin, and these are preferably dispersed in the polysilane compound alone or in combination in the form of powder or ultrafine particles.

A specific dispersion method is to mix the refractive index adjusting agent in the form of powder or ultrafine particles into a polysilane solution (a polysilane compound dissolved in a solvent) prepared when forming a film of a polysilane compound, and stir thoroughly. It is desirable to set the prepared solution in various film forming devices and form a film.Also, in the case of sublimation M storage, etc., when forming a polysilane film, the ultrafine particles of the refractive index adjusting agent are directly applied to the film forming surface. It may also be mixed in by spraying it.

The refractive index adjusting agent is dispersed in the organic semiconductor layer made of a polysilane compound along the thickness direction of the organic semiconductor layer. The refractive index is determined as appropriate in relation to the refractive index of the polysilane compound film bonded to the film, but it is preferable that the refractive index gradually increases from the light incident side. Although it is preferable that the rate be relatively gentle, there is no particular problem even if the rate is stepwise as long as the difference in each rate of change is small.

Specifically, the method for forming the distribution shape is as follows: (if several types of preparation solutions with different concentrations of the refractive index adjusting agent to be mixed into the polysilane solution for forming the polysilanized compound film are prepared, A method of sequentially forming and laminating a polysilane film using a prepared solution, (11) in the step of discharging the polysilane solution, the amount of powder or ultrafine particles of the refractive index adjusting agent continuously introduced into the polysilane solution A method of coating or discharging onto a substrate while mixing and stirring while changing the refractive index adjusting agent, and a method of continuously changing the electrolysis voltage and continuously changing the concentration of the refractive index adjusting agent dispersed in the electrolytic solution. .

A method of continuously changing the sublimation rate of the fiVl polysilane compound and continuously changing the amount of the refractive index adjusting agent mixed into the sublimation atmosphere. Alternatively, there may be a method in which the composition of Type 1 is changed.

In the present invention, the concentration of the refractive index adjusting agent dispersed in the organic semiconductor layer composed of the polysilane compound does not impair the properties as an organic semiconductor and the physical and mechanical properties of the polysilane compound. It is desirable to keep the range within a range, and that range depends on the polysilane compound used,
and Class 14 of refractive index adjusting agents, which differ depending on the combination, so it is difficult to define them unambiguously.

In the present invention, by changing and dispersing the concentration and/or kind of refractive index adjusting agent along the film thickness direction in the organic semiconductor layer composed of a polysilane compound, it is possible to improve the refractive index from the interface with the metal layer and the insulating layer. It is possible to significantly increase the amount of light incident into the polysilane semiconductor layer, and as the amount of photoexcited carriers generated increases, the probability of generation changes in the film thickness direction, improving carrier mobility, and as a result, photoexcited carriers are generated. The photoelectric conversion efficiency as a power device is significantly improved.

In addition, in the present invention, by uniformly distributing the refractive index adjusting agent in the plane direction of the polysilane compound, stress in the polysilane film is relaxed and adhesion is improved, and film strength is also improved. It is possible to form a photovoltaic element that is compatible with various substrate materials and has excellent durability. Furthermore, not only specific wavelength components.

Because it can absorb light with a relatively wide range of wavelength components,
Its properties can be improved without photodeterioration.

Back layer 1 In the present invention, MIS (MeLal-1ns
Materials for the metal layer that can be suitably used to form the u1at, or-5 semiconductor junction are appropriately determined depending on the work function of the polysilane semiconductor used, and specifically include Au, PL, Ag, W,
Select from metal MR9 such as Cu and Ni.

Further, the thickness of the metal layer must ensure sufficient light transmittance, and is preferably 1 μl or less, more preferably 0.8 μl or less.

The above-mentioned four metal legs are formed by a vacuum evaporation method, an electron beam deposition method, a sputtering method, or the like.

Based on the present invention, MIS (Metal-1n
As an insulating layer material suitably used for forming a sulator-5 semiconductor Lorl junction,
Specifically, 5iOz, 5i3Na, Al2O:+, Ti
0z, metal oxides such as Ta105, metal nitrides, 1) S
Various silicate glasses such as G and the like can be mentioned.

Further, the thickness of the insulating layer is preferably 5 to 30 angstroms, more preferably 5 to 20 angstroms, in order to minimize the decrease in minority carrier tunneling probability and the decrease in open circuit voltage due to increase in barrier height. desirable.

As methods for forming these insulating layer materials, in addition to physical formation methods such as sputtering and vapor deposition, gas phase chemical reaction methods such as plasma CVD can be used, and are appropriately selected as desired.

Fork # The support 101 used in the present invention may be electrically conductive or insulating, and in some cases may be translucent.

Further, it may be non-transparent, but if light is to be incident from the side of the support 101, it is of course necessary to be transparent. Specific examples include Fe, N
i, Cr, Mg, A1. Mo, Ta, V, Ti, Nb,
Pb.

Examples include metals such as Au, Ag, and PT, and alloys thereof, such as stainless steel, duralumin, nichrome, and brass.

In addition to these, polyester, polyethylene, polycarbonate, cellulose, acede(・, polypropylene,
Polyvinyl chloride, polyvinylidene chloride, borisdylene,
Films or sheets of synthetic resins such as polyamide, polyimide, polyethylene terephthalate, and glass;
Ceramics etc. can be mentioned.

Also, Si, Ge, NaCl, CaFz, 1. iF,
Examples include those obtained by slicing a single crystal or polycrystal such as I'1aFz and weighting it into a wafer shape, and those obtained by epitaxially growing a substance with a lattice constant similar to these two.

The shape of the support may be a plate with a smooth or uneven surface, a long belt, or a cylinder depending on the purpose and use, and the thickness may be adjusted to form the desired photovoltaic element. This will be determined as appropriate, but if flexibility is required or if light is incident from the side of the support, it can be made as thin as possible within the range that allows it to fully perform its function as a support. . However, in manufacturing and handling of the support4
21. From the viewpoint of mechanical strength, etc. 2. Usually the thickness is 10 μm or more.

In the photovoltaic device of the present invention, appropriate electrodes are selected depending on the configuration of the device. Specifically, a lower electrode and a current collecting electrode can be mentioned.

Since the lower electrode used in the present invention is provided for the purpose of extracting current from the polysilane semiconductor layer, it is necessary to make good ohmic contact with the polysilane semiconductor layer.

The position of the lower electrode 102 used in the present invention varies depending on the material of the support 101 described above or the direction of light incidence.

For example, in the case of the layer structure shown in FIG. 1(A), the support 101
However, if a material having sufficient conductivity is used for the support 101, the lower electrode 102 is not provided and the support 101 can also serve as the lower electrode. - On the other hand, when the support body 101 is insulating,
Alternatively, even if the support lot is conductive, if the sheet resistance is high, the lower electrode 102 is always provided for current extraction.

In the case of FIG. 1(B), a transparent support 101 is used, and light enters from the support 101 side, so @
A polysilane semiconductor layer 103 is provided facing the support 101 for the purpose of taking out the flow and reflecting light at the electrode.

As electrode materials, AIJg, Cr, Cu, Ag, ^
u, PL, Ti.

Examples include metals such as MoJ, and alloys thereof, and these are appropriately selected and used depending on the characteristics of the polysilane semiconductor layer. Each thin layer of these metals is formed by vacuum evaporation, 1M beam evaporation, sputtering, or the like. Furthermore, it is desirable that the formed metal thin film has a sheet resistance value of preferably 50Ω or less, more preferably IOΩ or less.

Fiil Current Collector Electrode The current collector electrode 107 used in the present invention has a metal layer 105
and is provided on the anti-reflection film 106 for the purpose of reducing the surface resistance value of the anti-reflection film 106.

Examples of electrode materials include Ag, Cr, Ni, Al. A
u, Pt.

Examples include metals such as Ti, W, Mo, and Cu, or alloys thereof. These metal thin films can be used in a stacked manner. Further, the shape and area of the semiconductor layer are appropriately designed to ensure sufficient light incidence on the semiconductor layer.

For example, it is desirable that the shape spreads uniformly over the light-receiving surface of the photovoltaic element, and that its area is preferably 15% or less, more preferably 10% or less of the light-receiving area.

Further, the sheet resistance value is preferably 50Ω or less, more preferably IOQ or less.

FIG. 1: IL Film In the photovoltaic device of the present invention, it is effective to provide an antireflection film 106 on the metal layer 105 in order to increase light collection efficiency.

The pus is required to have an optical anti-reflection effect and also has the function of an electrode for extracting current from the metal layer.

Therefore, it is desirable that the transmittance in the visible light range is 85% or more! I! The thickness is set to an appropriate film thickness that satisfies the anti-reflection condition with a 0.8 μm error. of course.

It is also possible to use a stack of thin films made of materials with different refractive indexes.

Regarding electrical conductivity, it is desirable that the sheet resistance value be less than IOOQ so as not to become a resistance component with respect to the output of the photovoltaic element.

Specifically, materials with such characteristics include:
Sn0m, TntOX, 2nO, CdO, rTOfln
103+SnO! Examples include metal oxide thin films of No. 1 class.

As a method for forming these metal oxide thin films, reactive resistance heating evaporation, electron beam evaporation, reactive sputtering, spraying, etc. can be used, and the method is appropriately selected according to needs.

In the present invention, as a means for forming a good MIS bond, the interface between the polysilane semiconductor layer and the insulating layer and the interface between the insulating layer and the metal layer are formed continuously in a vacuum or in an inert gas atmosphere. This is desirable.

In particular, when producing a polysilane semiconductor layer by a method using a solvent, it is necessary to thoroughly dry the solvent. Furthermore, it is preferable to dry the solvent at a temperature that does not exceed the glass transition point of the polysilane compound.

[Example 1] The photovoltaic device of the present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples in any way.

[Synthesis Example 1 First, a synthesis example will be given to explain in more detail the method for synthesizing the polysilane compound used in the present invention, but the method for synthesizing the polysilane compound used in the present invention is not limited to these methods. .

A three-way flask was prepared in a glove box that had been vacuum-suctioned and replaced with argon, 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 g of dehydrated dodecane and 0.3 mol of wire-shaped sodium metal were placed in this Mitsurofask, and 0.1 mol of zero-order dichlorosilane monomer (manufactured by Chisso ■) (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 condensation polymerization at 100° C. for 1 hour. This is followed by cooling, decanting the dodecane, and adding 100 grams of dehydrated toluene to dissolve the white solid, followed by 0.5 g of sodium metal. Next, 1 mole of tl was added, and then n-hexyl chloride (manufactured by Tokyo Kasei) (b-3) 0. A solution prepared by dissolving old moles in 10 ml of toluene was slowly added dropwise to the reaction system while stirring, and heated at 1. O0°C for 1 hour. After this, it was cooled and the excess metal sodium was removed. Therefore, 50 ml of methanol was slowly added dropwise to form a suspended layer and a toluene layer.

Next, the toluene layer was separated, concentrated under reduced pressure, and purified by developing with silica gel column chromatography to obtain polysilane compound ff1l (C-1,). Yield is 65%
Met.

The weight average molecular weight of this polysilane compound was determined to be 75. ODD (polystyrene standard).

For identification, create an IR pellet in N1colet
It was measured using FT-IR750 (manufactured by Collet Japan). In addition, for NMR, the sample was dissolved in CDCl5 and F
T-NM"RFX-90Q (manufactured by JEOL Ltd.). The results are shown in Table 5.6 Note that in the polysilane compound obtained in the present invention, unreacted 5i-CI and by-product 5i- 0-Si.

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

A three-way flask was prepared in a glove box that had been vacuum suctioned and replaced with argon, 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.

In this Mitsuro flask, 100 grams of dehydrated dodecane and ■
Prepared by dissolving 0.1 mole of zero-order dichlorosilane monomer (manufactured by Jisso ■) (a-7) in 30 g of dehydrated dodecane. After 0 drops, the solution was slowly added dropwise to the reaction system.

When linearly polymerized at 100° C. for 2 hours, a white solid precipitated. 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-710,0
A solution prepared by dissolving 2 mol in 10 ml of toluene was slowly added dropwise to the reaction system with stirring.
Heated at ℃ 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.

Then, the toluene layer was separated and concentrated under reduced pressure.

It was developed by developing with silica gel column chromatography to obtain polysilane compound No. 2 (c-3). The yield was 72% and the weight average molecular weight was 92.000. The identification results are shown in Table 5.

1 Prepare a three-way flask in a glove box that has been vacuum suctioned and replaced with argon, and attach a reflux condenser, thermometer, and dropping funnel to it. I passed it.

Into this Mitsuro flask, 100 grams of dehydrated n-hexylamine, 1 ml, and 0.3 mole of metal sodium of 11 cubes were charged.
Dehydrated n-
A solution prepared by dissolving it in hexane was slowly dropped into the reaction system. After 0 dropwise addition, the mixture was fed and polymerized at 80° C. for 3 hours, and a white solid was precipitated.

After this, it is cooled, and the n-hexane is decanted.
Further, 100 g of dehydrated toluene was added to dissolve the white solid, and 0.01 mol of sodium metal was added to the solution, and benzyl chloride (manufactured by Tokyo Kasei) (b-1
2) 0. A solution of old moles dissolved in 10 ml of toluene was slowly added dropwise to the reaction system with stirring, and the mixture was heated to 80°C.
It was heated for 1 hour. Thereafter, the mixture was cooled, and 50+al 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 silica gel column chromatography to obtain polysilane compound No. 3 (c-4). The yield was 61% and the weight average molecular weight was 47,000. The identification results are shown in Table 5.

In addition, in this polysilane compound, unreacted 5i-
There were no IR absorptions attributed to CI, by-products 5i-0-3i, and 5i-0-R.

Synthesis Examples 4j15 and 5 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.

Yield 1 weight average molecular weight of synthesized polysilane, tni3
and NMR data are shown in Table 5.

In addition, in this polysilane compound, unreacted 5i-
There were no IR absorptions attributed to CI, by-products 5i-0-Si, and 5i-0-R.

Polysilane compound N was synthesized in the same manner as in Example 3, except that dichlorosilane monomer (manufactured by Jisso ■) (a-7) was condensed in the same manner as in Synthesis Example 3, and the terminal groups of the polymer were not treated.
o, D-1 was obtained. The yield is 60% and the weight average molecular weight is 4.
6.0 (JO). The identification results are shown in Table 5.

In addition, in this polysilane compound, IR absorption attributed to unreacted 5i-CI and by-products 5i-0 to H was observed in the terminal group.

Condensation polymerization was carried out in the same manner as in Synthesis Example 3 using the dichlorosilane monomer shown in Table 2 and changing the reaction time as shown in Table 2. Polysilane was synthesized using the compound in the same manner as in Synthesis Example 3 and purified to obtain polysilane compound No. 6-1O.

Yield, weight average molecular weight, l of synthesized polysilane compound
R15 and NMR are shown in Table 5.

In addition, on the right side of this polysilane compound, unreacted 5i-
There was no IR absorption attributed to CI, by-products Si~0-3i, 5i-0-R.

Polysilane compound No. D-2 was synthesized in exactly the same manner as in Synthesis Example 6 except that the reaction time of the dichlorosilane monomer in Synthesis Example 6 was changed to 10 minutes.

Yield, weight average molecular weight, I Fi of synthesized polysilane
and NMR are shown in Table 5.

Note that in this polysilane compound, unreacted 5i
-CI, by-products 5i-0-5i, 5i-0-
■R absorption attributed to R was not present at all.

Sodanho Kamijami 2↓A Synthesis was carried out in the same manner as in Synthesis Example 1 using the dichlorosilane monomer and end group treatment agent shown in Table 3.

Yield and weight average molecular weight of synthesized polysilane.

In and NMR data are shown in Table 5.

The copolymerization ratio of the silane monomers was determined from the number of protons in NMR.

83 A three-way flask was prepared in a glove box that had been vacuum suctioned and replaced with argon, and a reflux condenser, thermometer, and dropping funnel were attached to it, and argon gas was passed through the bypass pipe of the two dropping funnels. .

100 grams of dehydrated dodecane and 0.3 mol of wire-shaped sodium metal were placed in this Mitsuro flask, and while stirring, 0.1 mol of primary dichlorosilane monomer (manufactured by Chisso ■) heated to 100°C was added to 30 g of dehydrated dodecane. After 0 drops, the solution prepared by dissolving in grams was slowly added dropwise to the reaction system.

A white solid was precipitated by condensation polymerization at 100° C. for 1 hour. Thereafter, the mixture was cooled, and 50 ml of methanol was slowly added dropwise to remove excess metal sodium.

Next, a white solid was produced and washed repeatedly with n-hexane and methanol to obtain polysilane compound No. D-3.

This polysilane compound? , f) Because it is insoluble in organic solvents such as toluene, chloroform, and THF, identification was performed by IR. The results are shown in Table 5.

Yoshu Mameboshu A Prepare a Mitsuro flask in a glove box with vacuum suction and argon replacement, attach a reflux condenser, thermometer, and dropping funnel to it, and supply argon gas from the bypass pipe of the dropping funnel. did.

100 g of dehydrated dodecane and 0.3 mol of wire-shaped sodium metal were placed in this Mitsuro flask and heated to 100° C. while stirring twice.

Next, a solution prepared by dissolving 0.1 mole of diphenyl dichlorosilane monomer (manufactured by Chisso ■) in 30 grams of dehydrated dodecane was slowly added dropwise to the reaction system.
A white solid was precipitated by linear polymerization at ℃ for 1 hour.

After this, it is cooled and the excess metal sodium is disposed of.
Methanol 50II11 was slowly added dropwise.

Next, a white solid was produced and washed repeatedly with n-hexane and methanol to obtain polysilane compound No. D-4.

This polysilane compound contains toluene, chloroform, T
) (Because it is insoluble in organic solvents such as F, identification was performed by IR. The results are shown in Table 5.

Synthesis was carried out in the same manner as in Synthesis Example 1 using the dichlorosilane monomer and end group treatment agent shown in Table 4.

Table 5 shows the yield, weight average molecular weight, JR and NMR data of the synthesized polysilane.

The copolymerization ratio of the silane monomers was determined from the number of protons in NMR.

The MIS junction type photovoltaic device 100 shown in FIG.
A stainless steel substrate 101 with an opening size of xO12 is placed in a sputtering device and evacuated to less than 1 O''' Torr, and then the internal pressure is reduced using Ag (purity 99.9999%) as a target metal and Ar gas as a sputtering gas. About 1200 Ag thin films, which will become the lower electrode 102, were deposited on the substrate 101 at room temperature at 5 pTorr and RF discharge power of 200 W.

Next, toluene l! which has been sufficiently dehydrated in advance! Polysilane compound No. 1 (c-1) synthesized in Synthesis Example 1 above
) was prepared by dissolving 200 parts by weight of the coating solution, and 1,0.0.
9, 0.8, Q, 7, 0.6, 0.5.0.
4.

0.3, 0.2, and 0.1 mg were mixed and sufficiently stirred to prepare 10 types of preparation solutions (1) to (10) for forming polysilane films. These were then placed in the 10-case liquid reservoir of a spin coater installed in a glove box with atmosphere A.

Subsequently, the substrate 10 is formed up to the lower electrode 102.
1 was taken out from the sputtering apparatus under an Ar atmosphere, which is an inert gas, and immediately set in a spin coater installed in the glove box. An Ar-filled carrier box was used to transfer the substrate.

First, using a spin coater in an Ar air flow, the lower electrode 10 is coated using a preparation solution (10) for forming a polysilane film.
A polysilane semiconductor film having a thickness of approximately 250 nm is formed on the film at room temperature, and then a preparation solution for forming a polysilane film (
9) to (11) were used to stack and form a polysilane semiconductor film by approximately 250 people, forming a polysilane semiconductor layer 103 in which SiO□ ultrafine particles were dispersed and distributed in the film thickness direction. The solvent was dried while heating 101 to 70°C.

Next, the substrate 101 on which the polysilane semiconductor layer 103 has been formed by the above operation is taken out into an Ar-filled carrier box, and immediately set in an RF plasma CVD apparatus, and while heating the substrate temperature to 70 ° C. -3
After evacuation to below Torr and sufficient degassing,
S i 114 gas 2.5sec, L gas 0,5
The polysilane semiconductor layer 103 was introduced with a discharge power of +8W while maintaining the internal pressure at 25 Torr.
One Si,02 film was deposited on the soil as an insulating layer 104.

Next, the substrate 1 formed up to the insulating layer 104 by the above operation
01 was taken out into an Ar-filled carrier box, immediately set in a DC magnetron sputtering device, the substrate temperature was set to 70"C, and AI (purity 99.9
999%) as a target metal and Ar gas as a sputtering gas, the metal layer 105 was formed on the insulating layer 104 at an internal pressure of 5 mTorr and a sputtering voltage of 300 V.
A 5° thick AI thin film was deposited.

Subsequently, in the sputtering apparatus, the AI target was replaced with the previously set InJs-3nOz sintered target, and Ar10*/Hz (100/4
010.5) was used as the sputtering gas, the internal pressure was 4 mTorr, and the sputtering voltage was 375.
An rTO film was deposited as an antireflection layer 106 on the metal N105 by 700 people.

After cooling, the substrate] 01 on which the antireflection layer 106 has been formed is taken out, and a comb-shaped permalloy mask for forming a collector electrode pattern is brought into close contact with the upper surface of the antireflection layer 106, and set in a vacuum evaporation apparatus. After evacuation to 10-' Torr or less, the antireflection layer 106 is heated by a resistance heating method.
AgFil [I
μm was deposited.

The photovoltaic device formed by the above-described operation was designated as Device 1, and its characteristics were evaluated as follows.

First, from the antireflection layer 106 side of the element barrier 1, the wavelength is 480n.
The photoelectric conversion efficiency was measured when light was irradiated with a light intensity of 0.1 mW/am".Furthermore, when the light intensity was changed to 0.2 mW7cm" and 0.3 mW/cm" without changing the wavelength. The photoelectric conversion efficiency was measured.

Furthermore, AMI light (100 mW/cm2
) After continuous irradiation for 10 hours, the photoelectric conversion efficiency (wavelength 480 nm, light intensity 0.1 mW/cm"
) was measured, and the rate of change with respect to the initial photoelectric conversion efficiency was determined.

In addition, the device 1 was set in a bending tester, and a bending test was repeated 103 times to evaluate changes in film adhesion and photoelectric conversion efficiency.

The above evaluation results are shown in Table 6.

From these results, the photovoltaic device fabricated in this example showed high photoelectric conversion efficiency regardless of changes in light intensity, had little photodeterioration, had strong mechanical strength, had excellent adhesion, and was stable. The characteristics were shown.

In place of polysilane compound No. 1 (c-1) used in forming the polysilane semiconductor layer 103 in Example 1, polysilane compounds No. 2 to 5 synthesized in the aforementioned Synthesis Examples 2 to 5 were used. Photovoltaic devices were prepared using the same procedure except that the photovoltaic devices were numbered 2 to 5.

The same measurements and evaluations as in Example 1 were performed on these elements. The evaluation results are shown in Table 6.

These results show that the photovoltaic devices produced in this example all exhibit high photoelectric conversion efficiency regardless of changes in light intensity, have little photodeterioration, and have strong mw intensity.
It exhibited excellent adhesion and stable properties.

! In Example 1, polysilane compounds No. 1 (c-) used in forming the polysilane semiconductor layer 103 were replaced with polysilane compounds No. 6 to 10 synthesized in Synthesis Examples 6 to 10 described above. As in Example 1, a polysilane semiconductor layer 103 with a refractive index changed in the film thickness direction was formed. Also, as the lower electrode 102, a C" thin film was used instead of the Ag thin film. As for ^1
A photovoltaic device was produced in the same manner except that 30 ^U thin films were deposited instead of the thin film, and the device number was 6~]O.

The same measurements and evaluations as in Example 1 were performed on these elements. The evaluation results are shown in Table 6.

From these results, all of the photovoltaic devices produced in this example showed high photoelectric conversion efficiency regardless of changes in light intensity, had little photodeterioration, and had strong mechanical strength.
It exhibited excellent adhesion and stable properties.

In Example 1, instead of the polysilane compound 1kl (c-1) used when forming the polysilane semiconductor layer 103,
Using the polysilane compounds Nos. 11 to 14 synthesized in the aforementioned Synthesis Examples 11 to 14, 5i as a refractive index modifier was prepared.
Instead of n2 ultrafine particles, WO, ultrafine particles (average particle size 90
A polysilane film-forming adjustment solution was prepared in the same manner as in Example 1, and a polysilane semiconductor layer 103 having a thickness of about 270 OA with a refractive index changed in the film thickness direction was formed by the same operation, and the insulating layer 104 was Photovoltaic devices were fabricated using the same procedure except that 10 PSG films were deposited instead of the SiO2 film, and device Nos. 11 to 14 were prepared.

The same measurements and evaluations as in Example 1 were performed on these elements. The evaluation results are shown in Table 6.

In addition, in the same table, by the same operation as Examples 1 to 14,
However, the evaluation results obtained when no refractive adjustment agent was included are shown in parentheses as a comparative example.

From these results, all of the photovoltaic devices fabricated in this example showed high photoelectric conversion efficiency regardless of changes in light intensity, little photodeterioration, strong mechanical strength, and good adhesion. It showed excellent and stable characteristics.

In Example 1, polysilane compounds m1 (c-1) used in forming the polysilane semiconductor layer 103 were replaced with polysilane compounds 15 to 17 synthesized in Synthesis Examples 15 to 17 described above. A photovoltaic device was fabricated in the same manner as in Example 1, except that a polysilane semiconductor layer 103 whose refractive index changed in the film thickness direction was formed using the same method as in Example 1.
~17.

The same measurements and evaluations as in Example 1 were performed on these elements. The evaluation results are shown in Table 7.

From these results, the photovoltaic devices produced in this example all exhibited high photoelectric conversion efficiency regardless of changes in light intensity, had little photodeterioration, and had strong mechanical strength.
It exhibited excellent adhesion and stable properties.

Examples 18 to 21 Instead of the stainless steel substrate 101 used in Examples 1, 6, 11, and 15, I) ET (
A photovoltaic device was produced by the same operation except that a substrate 101 made of N (100 μm thick) was used.
And so.

The same measurements and evaluations as in Example 1 were performed on these elements. The evaluation results are shown in Table 7.

In addition, in the same table, evaluation results obtained in the same manner as in Examples 15 to 21 but without the refractive index adjusting agent are shown in parentheses as comparative examples.

From these results, both of the photovoltaic devices fabricated in this example exhibited high photoelectric conversion efficiency regardless of changes in light intensity, and exhibited little photodeterioration.

It exhibited strong mechanical zero strength, excellent adhesion, and stable properties.

Fukumasu 22 A photovoltaic device was fabricated in the same manner as in Example 1, except that a 5-inch n'' Si single crystal wafer was used instead of the stainless steel substrate 101, and was designated as device Na22.

When this element was irradiated with light separated by a monochromator from the antireflection layer 106 side and the collection efficiency was measured, it was 70% in the visible light region where maximum absorption occurs.

Further, the FF was 0.55 when irradiated with sunlight of 80 W/cm''.

Table 1 Table 2 Table 3 Table 4 Table 6 (Part 1) Table 6 (Part 2) Table 7 [Effects of the Invention] As described in detail above, the photovoltaic device of the present invention has a short It has high sensitivity to wavelength light, and can significantly improve photoelectric conversion efficiency compared to conventional photovoltaic elements using organic semiconductors.

The polysilane compound used in the photovoltaic device of the present invention is easily soluble in many types of solvents and has excellent film-forming ability, so that it can be uniformly formed over a large area.
It has excellent adhesion to the support and excellent uniformity of properties.

The polysilane compound used in the present invention has excellent property stability, and changes in photoelectric conversion efficiency over time are significantly smaller than those of conventional photovoltaic elements using organic semiconductors.

Furthermore, the phenomenon of a decrease in photoelectric conversion efficiency due to an increase in the amount of incident light is also significantly improved. Furthermore, it has excellent heat resistance, and stable output characteristics can be obtained even under conditions of severe temperature changes.

Further, the photovoltaic device of the present invention has reduced photodeterioration and excellent physical and mechanical properties.

Furthermore, in the photovoltaic device of the present invention, the refractive index adjusting agent is distributed and dispersed in the new polysilane semiconductor layer along the film thickness direction, so that the refractive index adjusting agent is distributed from the interface with the metal layer and the insulating layer into the polysilane semiconductor layer. It is possible to significantly increase the amount of light incident on the photovoltaic element, and as the amount of photoexcited carriers generated increases, the probability of their generation changes in the film thickness direction, improving carrier mobility, and as a result, the photovoltaic element As a result, photoelectric conversion efficiency is significantly improved.

Furthermore, in the present invention, by uniformly dispersing and distributing the refractive index adjusting agent in the plane direction of the polysilane compound, stress in the polysilane film is relaxed, adhesion is improved, and film strength is also improved. , it is possible to form a photovoltaic element that is compatible with any substrate material and has excellent durability. Furthermore, since it becomes possible to absorb not only a specific wavelength component but also light of a relatively wide range of wavelength components, its characteristics can be improved without photodeterioration.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a photovoltaic device according to the present invention. +00...Photovoltaic element 101...Support, 10
2... Lower electrode 103... Polysilane semiconductor layer 104... Insulating layer 105... Metal layer 106
...Anti-reflection layer 107...Collecting electrode patent applicant Canon Corporation

Claims (1)

[Claims] 1. General formula (I) ▲There are numerical formulas, chemical formulas, tables, etc.▼... (I) (However, in the formula, R_1 is an alkyl group having 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' each represent an alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group having 4 to 12 carbon atoms, and they may be the same or different. n and m are molar ratios indicating the ratio of the number of each monomer to the total monomers in the polymer, and n
+m=1, 0<n≦1, 0≦m<1. ) and has a weight average molecular weight of 6,000 to 200,000 as an organic semiconductor layer, and a refractive index adjuster is distributed along the thickness direction of the organic semiconductor layer. type photovoltaic element. 2. The photovoltaic device according to claim 1, wherein in the polysilane compound represented by general formula (I), A and A' are an alkyl group having 5 to 12 carbon atoms or a cycloalkyl group. 3. The photovoltaic device according to claim 1, wherein the refractive index of the organic semiconductor layer gradually increases along the direction of light incidence.