JPH04199687A - photovoltaic element - Google Patents

Abstract

PURPOSE:To enable a photovoltaic element to be enhanced in photoelectric conversion efficiency by a method wherein an organic semiconductor layer is formed of polysilane compound which is 6000-200000 in weight-average molecular weight and provided with alkyl groups, cycloalkyl groups, and aryl groups which are all specified. CONSTITUTION:In an SIS junction type photovoltaic element, an organic semiconductor layer is formed of polysilane compound which is represented by Formula I and 6000-200000 in weight-average molecular weight. In Formula I, R1 is an alkyl group of 1 to 2 carbon atoms, R2 is an alkyl group, a cycloalkyl group, or an aryl group whose number of carbon atoms is 3-8, and R3 and R4 are an alkyl group whose number of carbon atoms is 1-4 respectively. At this point, the numbers n and m are so set as to satisfy a formula, n+m=1, and refractive index controlling agent is distributed along the thicknesswise direction of the semiconductor layer. The polysilane compound concerned is not provided with a chloro-group or a secondary reaction producing group at all, where all Si groups are replaced with specific organic groups which contain no oxygen, and the polysilane compound concerned is excellent in film forming properties. The polysilane compound is comparatively high in sensitivity to light of short wavelengths. By this setup, a photovoltaic element can be increased in open- circuit voltage and remarkably enhanced in photoelectric conversion efficiency.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a SIS 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.

[Conventional Technology J 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, virol, etc. Among them, merocyanine, phthalocyanine, hydroxyne squaryllium, etc. are suitable for photovoltaic devices. The photoelectric conversion efficiency of the Schottky barrier cell is approximately 0 under AMO spectrum light.
．． It is about 2 to 1%. [Jpn J, Appl,
Phys,,20゜5upp1.20-2.135 (
1980), App, 1. Phys, Lett.
, 32.495 (1978), J. Chem, Ph.
ys, , 71.1211 (1,979) ] The reason for such a low photovoltaic conversion rate is mainly due to the high carrier trap density in organic semiconductors. It is thought that this is because the length is also short.

Furthermore, since organic semiconductors generally have a high resistivity, it is difficult to make ohmic contacts, and furthermore, problems have been pointed out, 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 ancient times, polysilane was reported to be insoluble in solvents [The Journal of the American Chemical Society; ±, 2291pp (1924)],
In recent years, it has been reported that polysilane is soluble in solvents and can be easily formed into films [The Journal of the American Ceramic Society; Dan, 504 p.
p (1978)] began to attract attention. Furthermore, since polysilane photodecomposes when exposed to ultraviolet rays, research has been reported to apply it to resists [JP-A-60-984]
No. 31, JP-A-60-119550].

In addition, polysilane has the property of a photosemiconductor in which charge can be transferred through the σ-bonds in its main chain, and it is expected to be applied to electrophotographic photoreceptors [Physical Review; B length, 2818 pp (1987)]. Became. However, in order to be applied to such electronic materials, polysilane compounds must not only be soluble in solvents and capable of forming films, but also be capable of forming films without minute defects and with high homogeneity. . Since even minute defects are unacceptable in electronic materials, there is a demand for high-quality polysilane compounds that have clear substituent structures 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
A structure in which the base is substituted with an organic group has been reported [Journal of American Chemical Society [Journal of American Che
mical 5ociety; 94. (11)3
806 pp (1972)], ]Special Publication 1986-380
Publication No. 33] 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. However, both have a degree of polymerization of 2 to 6.
, and does not exhibit macromolecular characteristics. In other words, due to its low molecular weight, it does not have film-forming ability as it is, making it difficult to use industrially. High molecular weight polysilane compound removes all Si
A structure in which the base is substituted with an organic group has recently been reported [Nikkei New Materials, August 15 issue, page 46 (19
88)] Since the process involves special reaction intermediates, a decrease in the synthesis yield is expected, making industrial mass production difficult.

In addition, a method for synthesizing polysilane compounds is described in [The Journal of Organometallic Chemistry, 198
pp, C27, (1980) or The Journal of Polymer Science, Polymer Chemistry Edition; Vol, 22, 159-170pp (19
84)]. However, all of the reported synthesis methods involve only a condensation reaction of the polysilane main chain, and there is no mention of terminal groups. In any of the synthesis methods, unreacted chlorine groups and byproducts are produced due to side reactions, and the ability to constantly obtain the desired polysilane compound is dependent on efficiency.

Examples of using the above-mentioned polysilane compounds as photoconductors have also been reported (U, S, P, 隘461855
1, u, s, p, 隘4772525, JP-A-62-
269964), the influence of unreacted chloro groups and by-products due to side reactions is presumed.

In U, S, P, Nl 4618551, the above-mentioned polysilane compound is used as an electrophotographic photoreceptor, but although the applied potential is only 500 to 800 V in a general copying machine,
An abnormally high applied potential of 1000 V is used. This is thought to be because, at a normal potential, structural defects in polysilane cause defects in the electrophotographic photoreceptor, and the abnormal spot-like phenomenon on the image disappears. 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 provide a photovoltaic element that is stable against changes in incident light intensity and changes over time.

Another object of the present invention is to provide a photovoltaic device that increases the amount of light incident on the photovoltaic device and improves photoelectric conversion efficiency.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present inventor has made extensive research, and it has been found that a linear polysilane compound represented by the following general formula (1) can be used as a conventional organic semiconductor. They discovered that the characteristics were dramatically improved compared to the conventional photovoltaic device, and completed research to make it fully operational and functional as a photovoltaic device. The main points are (1)
) General formula (I) (wherein, R+ 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,
An aryl group or an aralkyl group, R3 represents an alkyl group having 1 to 4 carbon atoms, and R4 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 proportion of each monomer number to the total monomers in the polymer, and n+m=
1, and 0<n≦1.0≦m<1. ) and having a weight average molecular weight of 6,000 to 200,000 as the organic semiconductor layer, and a refractive index adjusting agent having a refractive index different from that of the organic semiconductor is distributed along the thickness direction of the organic semiconductor layer. In the polysilane compound that constitutes the SIS junction type photovoltaic device and is represented by the general formula (1), A and Ao are an alkyl group having 5 to 12 carbon atoms, or a cycloalkyl group; Furthermore, (3) the refractive index of the organic semiconductor layer gradually increases along the direction of light incidence.

Hereinafter, five aspects of the present invention will be explained in detail.

The novel polysilane compound provided by the present invention, represented by the formula (1) and having a weight average molecular weight of 6,000 to 200,000, has no chlorine groups or side reaction-forming groups, and all SL groups do not contain oxygen. Substituted with a specific organic group, without a prefix, toluene, benzene,
It is easily soluble in aromatic solvents such as xylene, halogenated solvents such as dichloromethane, dichloroethane, chloroform, and carbon tetrachloride, and 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 toughness.
It is rich in ssl.

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.
Desirably, it is a group selected from the group consisting of a cycloalkyl group, an aryl group, and an aralkyl group. In this case, the most preferred polysilane compound of the present invention is one in which 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 novel polysilane compound provided by the present invention can generally be synthesized as follows. That is, in a high-purity inert atmosphere free of oxygen and moisture, 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, and the resulting polymer It is synthesized by separating unreacted monomers from the polymer, and reacting the polymer with a predetermined halogenated organic reagent in the presence of a condensation catalyst made of an alkali metal to condense an organic group at the end of the polymer.

In the above synthesis operation, the starting material dichlorosilane, the intermediate polymer, the halogenated organic reagent, and the alkali metal condensation catalyst are all highly reactive with oxygen and moisture, so it is necessary to avoid the presence of oxygen and moisture. 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 dehydrated by passing it through a silica gel column in advance, and then deoxidizing the copper powder by passing it through a column heated to 100'C.

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 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 atmosphere of an inert gas such as ^r, Nx, etc. to prevent oxidation.

The dichlorosilane monomer used as a starting material for producing the novel polysilane compound represented by the general formula (I) of the present invention is a silane compound represented by the following formula: R+RzSIC1t, or a silane compound represented by the formula: R5Ra5.
Silane compounds designated by iC1* are 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 Ao, and is a group consisting of a halogenated alkyl compound, a halogenated cycloalkyl compound, a halogenated aryl compound, and a halogenated aralkyl compound. A suitable compound selected from:
-X and/or -Formula: A' -x (where X is ci
or Br), and appropriate compounds from the specific examples described below are selectively used.

General formula used in synthesizing the above intermediate polymer: R5Ra5iC1* or this - formula: RaR4
The dichlorosilane monomer represented by 5IC12 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-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 monomer.6 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 comprises (i) producing an intermediate polymer;
) Introducing substituents A and Ao to the terminals of the intermediate polymer.

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.
An anhydrous paraffinic solvent and an anhydrous condensation catalyst are added, followed by an anhydrous dichlorosilane monomer, and the whole is heated to a predetermined temperature while stirring to condense the monomers. At this time, the degree of condensation of the dichlorosilane monomer is controlled by adjusting the reaction temperature and reaction time so that an intermediate polymer having a desired degree of polymerization is produced.

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.

R,R.

The specific reaction procedure is as follows: 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.

Next, the step (11) is carried out, 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) to obtain a predetermined polymer terminal group. Substitute with an organic group. The reaction at this time is represented by the following reaction formula (it).

(However, A=A' may also be used.) Specifically, an aromatic solvent is added to the intermediate polymer obtained by condensation of dichlorosilane monomers and dissolved. 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 polymer end groups, a halogenated organic agent is added in an equivalent amount to the starting monomer, and an additional 0. An excess amount of O1 to 0.1 times the equivalent is added. Gradually heat to 80℃~100℃
Heat and stir 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, 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.

R3R81C1, and R5R45t (:im note): Among the following compounds, a -2 ~ 16, 18, 20, 21゜2
3,24 is used for R5R45iC1x, a-1,2
゜11.1? , 19, 22, 23.25 are R5R45i
Used for C1x.

(cH,) *5ictt a-1(
fcH,1tcHh 5iC1,a-22f(C1,1
iC1! 5iCI2 a-25A-X and A'-X - Examples (CI1, CHCl1.CI
, b-IC11, (CIl, 14
CI b-2CI+,
(CH,l SC1b-3 C1l, fcll,l I, C1b-4CHI 1
cI1. l %Br b-
14CIls (cHtl + o Kano
b-15 Further, specific examples of the polysilane obtained are shown below.

CH3 gourd CH.

C.I.

C! H5 C11゜ ■ 1h ■ G.H.

CH.

C.I.

CIIm(CL) s + Si +T-(CI-)
sCH.

ξ CH(CH-1*c-18C
HICH, l.

CIl.

C11゜ CIl, CH.

C113C)I.

CH, CI.

Hs ■ CH.

CH.

■C11゜Note): In the above structural formula, both X and Y represent monomer polymerization units, and n is X/ (X+Y), or m is Y
/ (X+Y), respectively.

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 manufactured by SIS (Semiconductor)
nduc-tor In5ulator Sem1co
By forming a junction (inductor), minority carriers generated in the polysilane semiconductor layer can be effectively used to obtain a high open circuit voltage.

Furthermore, since the polysilane compound used in the photovoltaic device of the present invention is sensitive to relatively 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 tailored 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 the case of a metal layer, the height of the barrier caused by the work function of the metal, and in the case of an insulating layer, the height of the barrier and the magnitude of the tunneling probability of minority carriers greatly control the collection efficiency. It is necessary to select the material and film thickness appropriately.

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.

In the example shown in FIG. 1(A), a lower electrode 102 is placed on a support 101. A polysilane semiconductor layer 103 in which a refractive index adjusting agent is distributed along the thickness direction of the semiconductor layer 103, and an insulating layer 10
4. Semiconductors! 105, antireflection film 106, current collecting electrode 10
7 is deposited in this order.

Note that in this photovoltaic element, light is incident from the antireflection film 106 side.

In the example shown in FIG. 1(B), a current collector electrode 107, an antireflection film 106, a semiconductor layer 105, an insulating layer 104, and a refractive index adjuster are placed on a transparent support 101 in the thickness direction of the semiconductor layer 103. This is a photovoltaic device 100 in which a polysilane semiconductor layer 103 and a lower electrode 102 are deposited in this order. Note that in this photovoltaic element, light is incident from the transparent support 101 side.

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 in the polysilane semiconductor layer by the refractive index adjusting agent dispersion method described later.

In order to form an SIS junction and obtain sufficient photoelectric conversion efficiency, the thickness of the polysilane semiconductor layer in which the refractive index adjusting agent is dispersed is preferably lnm to 5X10'nm, more preferably 5nm to +5X10'nff1, and optimally. is 10
It is preferable that the thickness is in the range of nm to 5×10′.

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

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

MgO, SiO, A1*0. CaCO5, MgFt, T
i0t, FezO5, CeO,.

Inorganic compounds such as wO, NaF, CdS, ZnS, BitOn, Be.

Mg, Ca, Sr, Ba, La, Ce, C
r, Mn, Nf, Cu, Ag, Au, AI
, metals such as Sb, ebonite, amber (, tartaric acid, sucrose, paraffin, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin, silicone resin, nylon, polyethylene, polyester, polystyrene, methyl methacrylate resin, melamine resin, etc. These organic compounds and synthetic resins are preferably dispersed in the polysilane compound alone or in combination in the form of powder or ultrafine particles.

As a specific dispersion method, the refractive index adjusting agent in the form of powder or ultrafine particles is mixed into a polysilane solution (a polysilane compound dissolved in a solvent) prepared when forming a film of a polysilane compound, and thoroughly stirred. It is desirable to set the prepared solution in various film forming devices and form a film.Also, when forming a polysilane film using a sublimation vapor deposition method, etc., ultrafine particles of the refractive index adjusting agent are directly applied to the film forming surface. It may be mixed by spraying.

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. Although the refractive index is appropriately determined in relation to the refractive index of the polysilane compound film bonded to the refractive index, it is preferable that the refractive index gradually increases from the light incident side. Although it is preferable that the rate of change of the refractive index is relatively gentle, there is no particular problem even if the rate of change is step-like as long as the difference between the rates of change is small.

Specifically, the method for forming the distribution shape includes (i) preparing several types of preparation solutions with different concentrations of the refractive index adjusting agent to be mixed into a polysilane solution for forming a polysilane compound film, and A method of sequentially forming and laminating a polysilane film using a prepared solution, (ii) a step of discharging the polysilane solution, in which the amount of powder or ultrafine particles of the refractive index adjusting agent is continuously introduced into the polysilane solution (iii) Continuously changing the electrolytic voltage and continuously changing the concentration of the refractive index adjusting agent dispersed in the electrolytic solution. (LV) a method of continuously changing the sublimation rate of the polysilane compound and continuously changing the amount of the refractive index modifier mixed into the sublimation atmosphere; (V) each of the above methods. Examples include a method in which the type or composition of the refractive index adjusting agent is changed instead of the concentration.

In the present invention, the concentration of the refractive index adjusting agent dispersed in the organic semiconductor layer composed of the polysilane compound is as follows:
It is desirable that the content be maintained within a range that does not impair the properties of the polysilane compound as an organic semiconductor, as well as its physical and mechanical properties. The range varies depending on the type and combination of the polysilane compound and refractive index adjusting agent used, and therefore it is difficult to define it unconditionally.

In the present invention, by changing and dispersing the concentration and/or type of refractive index adjusting agent in the organic semiconductor layer composed of a polysilane compound along the film thickness direction, 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 their generation changes in the film thickness direction, improving carrier mobility, and as a result, light The photoelectric conversion efficiency as an electromotive force element is significantly improved.

In addition, 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 light of a relatively wide range of wavelength components instead of only a specific wavelength component, its characteristics can be improved without photodeterioration.

Toyodo stop 1 In the present invention, SIS (Semiconductor)
tor In5-ulator Sem1conduc
tor) The material for the semiconductor layer that is suitably used for forming the junction can be any material that exhibits so-called semiconductor characteristics, and specifically, C, Si,
So-called group III semiconductors consisting of Group 1V elements of the periodic table such as Ge and Sn, Zn, Cd and O. Se, S
, so-called TI-Vl semiconductors, B, and AI, which are composed of elements of Group 1I and Group Vr of the periodic table, such as Te.

So-called ■-V group semiconductors consisting of Ga, In, N, P, As, Sb, Group 1II and Group II of the periodic table, and 5n02°In201. ZnO, CdO,
Examples include so-called oxide semiconductors in which metal oxides such as rTO (Tn20s+5nO2) are subjected to doping treatment.

Furthermore, the thickness of the semiconductor layer needs to sufficiently ensure the transmission of light to the polysilane semiconductor layer below, and is preferably 5 μm or less, more preferably 2 μm or less, and optimally 0.8 μm or less. It is desirable that there be.

On the other hand, by setting the semiconductor layer 105 to an appropriate thickness, it can also be used as an antireflection film 106.

The semiconductor thin film described above can be formed by a plasma CVD method, an HR-CVD method, a vacuum evaporation method, an electron beam evaporation method, a sputtering method, or the like, and can be appropriately selected according to needs.

Confidence 1 In the present invention, SIS (Semiconductor
tor In5-ulator 5ellicond
Specifically, SjO*, 5isN4 are suitably used insulating layer materials for forming the junction.
．． Metal oxides such as Al*Os, TfO*, Ta*Os, metal nitrides, various silicate glasses such as PSG,
and complex oxides that have adsorbed water.

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

As a method 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 these are appropriately selected depending on needs.

Scratch marks The support 101 used in the present invention may be conductive or insulating, and furthermore may be translucent or non-transparent. Although it may be a photosensitive material, it is of course necessary to be translucent when light is incident from the side of the support lO1. Specific examples thereof include Fe, Ni, Cr, Mg,
AI, Mo, Ta, V, Tj, Nb, Pb
.

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

In addition to these, examples include films or sheets of synthetic resins such as polyester, polyethylene, polycarbonate, cellulose, acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, and polyethylene terephthalate, as well as glass and ceramics. .

Also, Si, Ge, NaCl, CaFz, Li
Examples include those sliced from a single crystal or polycrystal such as F or BaFt and processed into a wafer shape, and those on which a substance with a similar lattice constant is epitaxially grown.

The shape of the support may be a smooth surface or a plate with an uneven surface, a long belt shape, a cylindrical shape, etc. depending on the purpose and use, and its thickness is determined as appropriate so as to form the desired photovoltaic element. However, when flexibility is required or when light is incident from the side of the support, it can be made as thin as possible within a range that allows the support to function adequately. However, from the viewpoints of manufacturing and handling of the support, mechanical strength, etc., the thickness is usually set to 10 LLm or more.

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

Dan 3 town! Since the lower electrode 102 used in the present invention is provided for the purpose of extracting current from the polysilane semiconductor layer 103, it needs to have good ohmic contact with the polysilane semiconductor layer.

The position of the lower electrode 102 used in the present invention differs 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 101 is conductive, if the sheet resistance is high, it is necessary to provide the lower electrode 102 for current extraction.

In the case of FIG. 1(B), a transparent support 101 is used, and since light is incident from the side of the support 101, the lower electrode 102 is used for current extraction and for light reflection at the electrode. For this purpose, a polysilane semiconductor N103 is provided facing the support 101 with a polysilane semiconductor N103 sandwiched therebetween.

As electrode materials, AI, Mg, Cr, Cu, A
g, Au, Pt, Ti.

Examples include metals such as Mo and W, and alloys thereof, and are appropriately selected and used depending on the characteristics of the polysilane semiconductor layer. Further, these metal thin films are formed by vacuum evaporation, electron beam evaporation, sputtering, or the like. Furthermore, the formed metal thin film preferably has a sheet resistance value of 50
It is desirable that the resistance is Ω or less, more preferably 10Ω or less.

Mametankuri 111 The current collecting electrode 107 used in the present invention is the semiconductor layer 10
5 and on the antireflection film 106 for the purpose of reducing the surface resistance value of the antireflection film 106.

The electrode materials include Ag, Cr, Ni, ^1. ＾u、
Pt, Ti, W, Mo.

Examples include metals such as Cu, and 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 10Ω or less.

1. In the photovoltaic device of the present invention, it is effective to provide an anti-reflection film 106 on the semiconductor layer 105 in order to increase the light collection efficiency, and furthermore, it is effective to provide the anti-reflection film 106 on the semiconductor layer 105.
It can also be used as li106.

The film is required to have an optical antireflection effect and also has the function of an electrode for extracting current from the semiconductor layer.

Therefore, it is desirable that the transmittance in the visible light region is 85% or more, and the film thickness is set to be approximately 0.8 μm, which is an appropriate film thickness that satisfies the anti-reflection conditions. 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 100Ω or less so as not to become a resistance component with respect to the output of the photovoltaic element.

Specifically, materials with such characteristics include 5
nOa, In2O5, ZnO, CdO, ITO(In
Examples include metal oxide thin films such as aOs+5nOz).

As methods for forming these metal oxide thin films, reactive resistance heating evaporation, electron beam evaporation, reactive sputtering, spraying, etc. can be used, and these methods are appropriately selected depending on needs.

In the present invention, as a means for forming a good SIS junction, the interface between the polysilane semiconductor layer and the insulating layer and the interface between the insulating layer and the semiconductor layer are formed continuously in a vacuum or an inert gas atmosphere. 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.

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

[Synthesis Example] First, the method for synthesizing the polysilane compound used in the present invention will be explained in more detail by giving a synthesis example, but the method for synthesizing the polysilane compound used in the present invention is not limited to these methods. do not have.

A Mitsuro 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 Mitsuroh flask and heated to 100° C. with stirring. Next, 0.1 mole of dichlorosilane monomer (Tisso side (a-7)) was added to 30% of dehydrated dodecane.
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. This is followed by cooling, decanting the dodecane, and adding 100 grams of anhydrous toluene to dissolve the white solid, followed by 0.0% sodium metal solution. To the 0th order to which old moles were added, n-hexyl chloride (manufactured by Tokyo Kasei) (b-3) 0. A solution of old moles dissolved in 10 ml of toluene was slowly added dropwise to the reaction system with stirring, and heated at 100° C. for 1 hour.

After this, it is cooled and the excess metal sodium is disposed of.
50 mJ2 of methanol was slowly added dropwise.

This produced a suspended layer and a toluene layer.

Next, the toluene layer was separated, concentrated under reduced pressure, and purified by spreading with silica gel column chromatography to obtain 1 kl of polysilane compound (C-1).

The yield was 65%.

The weight average molecular weight of this polysilane compound was determined to be 75.000 by GPC method using THF development (
(polystyrene standard).

For identification, IR produced a KBr pellet and N1colet
It was measured using FT-IR750 (manufactured by Collet Japan). In addition, for NMR, the sample was dissolved in CDCl5 and F
Measurement was performed using T-NMRFX-90Q (manufactured by JEOL Ltd.). The results are shown in Table 5.

In addition, in the polysilane compound obtained by the present invention,
Unreacted (7) Si-CI, by-product (7) Si-0-
3i.

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

A Mitsuro 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 dropping funnel's bypass.

In this Mitsuro flask, 100 grams of dehydrated dodecane and 1
0.3 mol of metal lithium (mm square) was charged and heated to 100°C with stirring.0-order dichlorosilane monomer (
(manufactured by Chisso) (a-7) 0.1 mol is dehydrated dodecane 30
A solution prepared by dissolving the solution in grams was slowly added dropwise to the reaction system, and then linear polymerization was carried out at 100° C. for 2 hours to precipitate a white solid. After this time, the white solid is dissolved by cooling, decanting the dodecane, and adding 100 grams of dehydrated toluene to dissolve the lithium metal.
02 mol was added.

Next, chlorobenzene (manufactured by Tokyo Kasei) (b-7) 0.0
A solution of 2 moles dissolved in 10 mj2 of toluene was slowly added dropwise to the reaction system with stirring, and the mixture was heated at 100°C for 1
heated for an 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 then developed and purified using silica gel column chromatography to obtain polysilane compound Th2 (c-3). The yield was 72%, and the weight average molecular weight measured by GPC was 92.000. The identification results are shown in Table 5.

A Mitsuro flask was prepared in a globe hox 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 dropping funnel's bypass pipe.

100 g of dehydrated n-hexane and 0.3 mole of metal sodium in a 1 mm square were placed in this Mitsuro flask and heated to 80° C. with stirring. Next, a solution prepared by dissolving 0.1 mole of dichlorosilane monomer (manufactured by Chisso) (a-7) in dehydrated n-hexane was slowly added dropwise to the reaction system. After 0 drops, line polymerization was carried out at 80°C for 3 hours. A white solid precipitated out.

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 then 0.01 g of metallic sodium was added.
Next, add 0.01 mole of benzyl chloride (manufactured by Tokyo Kasei) (b-12) to 10 ml of toluene.
A solution dissolved in the mixture was slowly added dropwise to the reaction system while stirring, and the mixture was heated at 80° C. for 1 hour. After this, cool
To dispose of excess sodium metal, methanol 50
ml was slowly added dropwise. This produced a suspended layer and a toluene layer.

Next, the toluene layer was separated and concentrated under reduced pressure, and then developed and purified by silica gel column chromatography to obtain polysilane compound Th3 (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 was no TR absorption attributed to CI, by-products 5i-0-Si, and 5i-0-H.

Synthesis was carried out in the same manner as in Example 3 using the dichlorosilane monomers and end group treating agents shown in Table 1 at Takumi Gohara.

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

In addition, in this polysilane compound, unreacted 5i-
There was no TR absorption attributed to CI, by-products 5t-0-3i, and 5i-0-H.

Polysilane Compound N
cD-1 was obtained. The yield was 60% and the weight average molecular weight was 46.
．． It was 000. The identification results are shown in Table 5.

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

Polycondensation 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 in the same manner as in Synthesis Example 3 using the following formula, and purified to obtain polysilane compounds 6 to 10.

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

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

Polysilane compound mD-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.

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

Note that in this polysilane compound, unreacted 5i
-CI, by-products 5i-0-5i, 5i-0-
There was no IR absorption assigned to R.

Containment 10-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.

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

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

1 Prepare a three-way flask in a glove box that has been vacuum-suctioned and replaced with argon, attach a reflux condenser, thermometer, and dropping funnel, and supply argon gas from the bypass pipe of the dropping funnel. did.

100 grams of dehydrated dodecane and 1.3 mol of wire-shaped sodium metal were placed in this Mitsuro flask and heated to 100'C while stirring. Next, 0.1 mol of dichlorosilane monomer (manufactured by Chisso) was dehydrated. dodecane 30
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. Thereafter, the mixture was cooled, and 50 ml of methanol was slowly added dropwise to remove excess metal sodium.

Next, the white solid was dried and washed repeatedly with n-hexane and methanol to obtain a polysilane compound PkLD-3.

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

Arashikou Sei 1 A Mitsuro flask was prepared in a glove box with vacuum suction and argon replacement, 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 heated to 100° C. with stirring.

Next, a solution prepared by dissolving 0.1 mole of diphenyl dichlorosilane monomer (manufactured by Chisso) in 30 grams of dehydrated dodecane was slowly dropped into the reaction system. After dripping, 100
A white solid was precipitated by condensation polymerization at ℃ for 1 hour.

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

Next, the white solid was dried and washed repeatedly with n-hexane and methanol to obtain polysilane compound D-4.

This polysilane compound contains toluene, chloroform, TH
Since 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, IR and NMR data of the synthesized polysilane.

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

An MIS junction type photovoltaic device 10d shown in FIG. 1(A) was fabricated by the following operations. Note that in this embodiment, the semiconductor layer 105 also serves as the antireflection layer 106.

First, the 100mm x 100mm x precision-cleaned
A stainless steel support 101 with a size of 0.2 mm is placed in a sputtering device and evacuated to below 10 Torr, and then 8g (purity 99.999'1%) is used as a target metal and Ar gas is used as a sputtering gas. used as
About 1,500 Ag thin films, which will become the lower electrode 102, were deposited on the support 101 at room temperature under an internal pressure of 5 mtorr and an RF discharge power of 200 W.

Next, a coating solution was prepared by dissolving 200 parts by weight of the polysilane compound N11 (c-1) synthesized in Synthesis Example 1 in toluene 14, which had been sufficiently dehydrated in advance, and this was further divided into 10 equal parts. , each with 5in2 ultrafine particles (average particle size 8
0 people) 1.0.9, 0.8.

0.7, 0.6, 0.5, 0.4, 0.3,
0.2 and 0.1 mg were mixed and thoroughly stirred to form a polysilane film formation preparation solution ((1) to (10)) of 10
We have prepared various types. Then, these were placed in the ]0 liquid reservoir of a spin coater installed in a glove box with an atmosphere of ^r.

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

A: Using a spin coater in an air stream, first use the polysilane film forming adjustment solution (10) to coat the lower electrode 10.
A polysilane semiconductor film with a thickness of approximately 250 nm is formed on the film at room temperature, and then a polysilane film formation conditioning solution (
Approximately 250 people stacked and formed a polysilane semiconductor film using each of 9) to (1) to form a polysilane semiconductor layer 103 in which 5iOz ultrafine particles were dispersed and distributed in the film thickness direction. Furthermore, the solvent was dried while heating the support 101 to 70° C. in an Ar gas flow.

Next, the support body 101, which has been formed up to the polysilane semiconductor layer 103 by the above operation, is taken out into an Ar-filled carrier box, and immediately set in an RF plasma CVD apparatus, while heating the substrate temperature to 70°C. 10-3To
After sufficiently degassing by evacuation to below rr, Si
H4 gas 2.2sec, 02 gas 0.5sec
was introduced, and the insulating layer 1 was formed on the polysilane semiconductor layer 103 with a discharge power of 28 W while keeping the internal pressure at 0.3 Torr.
15 people deposited a 5ins film as No. 04.

Next, the support 101, which has been formed up to the insulating layer 104 by the above operation, is taken out into an Ar-filled carrier box, and immediately set in a DC magnetron sputtering device, the substrate temperature is set to 70° C., and InzO3-5n01
Using a sintered body as a target, 8r10z/L (1
00/4010.5) was used as the sputtering gas and Ph3 gas was used as the doping gas, and the internal pressure was set to 3. A semiconductor layer 105 that also serves as an antireflection layer is formed on the insulating layer 104 at OmTorr and a sputtering voltage of 405 cm.
720 people deposited n-type ITOg.

After cooling, the support 101 on which the semiconductor layer 105, which also serves as an antireflection layer, has been formed is taken out, and a comb-shaped permalloy mask for forming a current collecting electrode pattern is closely attached to the upper surface of the semiconductor layer 105, and then transferred to a vacuum evaporation apparatus. and set it to 10-'T.
After evacuation to a temperature below orr, Ag is deposited as a comb-shaped current collecting electrode 107 on the semiconductor layer 105 by a resistance heating method.
A 1 μm thick N film was deposited.

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

First, from the antireflection layer 106 side of element No.
The photoelectric conversion efficiency was measured when irradiating light with a wavelength of 0.00 nm and a light intensity of 0.1 mW/cm2. Furthermore, the light intensity was changed to 0.2 mW/cm" and 0.3 mW/cm" without changing the wavelength.
The photoelectric conversion efficiency was measured when the

Furthermore, AMI light (100mW/cm"
) After continuous irradiation for 10 hours, the photoelectric conversion efficiency measured by the above measurement method (wavelength 500 nm, light intensity 0.1 mW/am2)
was measured, and the rate of change with respect to the initial photoelectric conversion efficiency was determined.

Also, set the element No./l on the bending Ml"J machine, and
A repeated bending test was performed 0' times, and changes in film adhesion and photoelectric conversion rate were evaluated.

The above evaluation results are shown in Table 6.

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

In Example 1, polysilane compound No. 1 was used when forming the polysilane semiconductor layer 103. A photovoltaic device was prepared using the same procedure except that polysilane compounds No. 2 to 5 synthesized in Synthesis Examples 2 to 5 above were used in place of (c-1), and device dimensions 2 to 5 were used. did.

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 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, instead of the polysilane compound kl (c-1) used when forming the polysilane semiconductor layer 103, polysilane compounds 6 to 10 synthesized in the aforementioned Synthesis Examples 6 to IO were used. As in Example 1, a polysilane semiconductor layer 103 whose refractive index changed in the film thickness direction was formed, and the lower electrode 102 was made of a Cr thin film instead of the Ag thin film, and the semiconductor layer 105 was made of n-type ITO. A photovoltaic device was fabricated using the same procedure except that a p-type SiC thin film was deposited instead of the thin film, and the device thickness was 6 to 10.
And so.

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.

Support I Craftsmanship Nut 1 In Example 1, instead of polysilane compound No. 1 (c-1) used when forming the polysilane semiconductor layer 103, polysilane compounds No. 11 to 14 synthesized in the aforementioned Synthesis Examples 11 to 14 were used. 5 as a refractive index modifier using
i(h) WO3 ultrafine particles (average particle size 9) instead of ultrafine particles
A conditioning solution for forming a polysilane film was prepared in the same manner as in Example 1, using a polysilane semiconductor layer 103 whose refractive index changed along the film thickness direction.
A photovoltaic device was fabricated using the same procedure except that a PSG film of 10 layers was deposited as the insulating layer 104 instead of a 5iOz film.
It was set at 14.

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, 1
However, the evaluation results obtained when no refractive index modifier is included are
Comparative examples are shown in parentheses.

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, instead of the polysilane compound Pb1 (c-1) used when forming the polysilane semiconductor layer 103,
A polysilane semiconductor layer 103 whose refractive index varied along the film thickness direction was formed in the same manner as in Example 1 using polysilane compounds 15 to 17 synthesized in Synthesis Examples 15 to 17 above, and as a semiconductor layer 105. The thickness of the n-type ITO film was changed from 700 to 350, and an ITO film as the antireflection layer 106 was deposited by 340 people under the same deposition conditions as the core layer except that pH 3 was not added. A photovoltaic device was prepared using the same procedure except for the following steps.
It was set at 7.

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, 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.

Instead of the stainless steel support 101 used in Examples 1, 6, 11, and 15, PET (
Photovoltaic devices were fabricated in the same manner except that a support 101 with a thickness of 10,100 μm was used, and devices Nos. 18 to 21 were prepared.

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, 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.

A photovoltaic device was produced in the same manner as in Example 1, except that a 5-inch Si single crystal wafer was used instead of the stainless steel support 101, and the device was used as the device support 22. .

When the collection efficiency was measured by irradiating light separated by a monochromator from the anti-reflection N106 side of this element, it was 67% in the visible light region where maximum absorption occurs.

Also, the FF when irradiated with sunlight of 80 mW/cm"
was 0.56.

(Hereafter) 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 present invention The photovoltaic device has high sensitivity to short wavelength light, and can significantly improve photoelectric conversion efficiency compared to conventional photovoltaic devices using organic semiconductors.

The polysilane compound used in the photovoltaic device of the present invention is easily soluble in many types of solvents.

It has excellent film-forming ability, so it can form a film uniformly over a large area, has excellent adhesion to a support, and has 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 light of a relatively wide range of wavelength components instead of only a specific wavelength component, 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 102
... Lower electrode 103 ... Polysilane semiconductor layer 104 ... Insulating layer 105 ... Semiconductor layer 10
6...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 the weight average molecular weight is 6000 to 200000
1. A SIS junction type photovoltaic device, characterized in that a polysilane compound having the following formula is used as an organic semiconductor layer, and a refractive index adjusting agent is distributed along the thickness direction of the organic semiconductor layer. 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.