JPS6341082A - photovoltaic device - Google Patents

Abstract

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

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to a photovoltaic device using a chalcopalite semiconductor having a molecular formula of Cu E nX□ (X is an element from group Ⅰ of the periodic table).

[Prior art and its problems]

Cu1nSez and Cu1nSz, which have a crystal structure similar to that of chalcopalite (yellow with XcuFes spirit), are semiconductors with a direct transition type band structure with a forbidden band width of about 1 eV.
Since it exhibits both p- and n-type calculators and has a high absorption coefficient, it is attracting attention as a material with the potential to produce highly efficient solar cells, and research and development is progressing. A photovoltaic device using this material generally has a heterojunction structure with n-type CdS. CdS is Cu1nXt
It is selected as the window layer on the light incident side because of the relatively small mismatch with the lattice of .

[Purpose of the invention]

The present invention aims to solve the problem of lattice mismatch when forming a heterojunction between a semiconductor having the molecular formula of CuInX and another semiconductor, and to provide a photovoltaic device with high performance. purpose.

[Key points of the invention]

The present invention configures a photovoltaic device with the amorphous silicon belly side of a heterojunction consisting of a - conductivity type CuJnL semiconductor film and a different conductivity type amorphous silicon side as the light incident side, and an example of the heterojunction is an amorphous silicon film. Since it is a semiconductor, there is no problem of lattice mismatch at the junction, and the above objective is achieved.

[Embodiments of the invention]

Figure 7fj1 shows an embodiment of the present invention, in which n-type polycrystalline Cu1 is placed on a metal substrate 1 made of stainless steel, for example.
An nSez film 2 is formed to a thickness of 1 to 3 μm, and then an n-type amorphous silicon film 3 doped with boron or the like is formed to a thickness of 100 μm.
Formed to a thickness of ~500 mm, followed by IT○, 5nO
A photovoltaic device is constructed by forming a transparent conductive film 4 such as z'1lf4 as a counter electrode to the substrate 1. In this case, the Cu1nSe film is CuC1, InC1, etc. (:HsNHC3eNHCHs (dimethylselenourea) aqueous solution is made into a mist using a spray method etc.
It was formed by chemically decomposing it by spraying it onto the substrate 1 heated to ~300°C. Note that this Cu1nSez film is Cu +
By simultaneous vacuum evaporation of I n + S e, or by printing on a powdered Cu1nSez compound and a paste with an organic material, 600
It can also be formed by sintering at ℃. The p-type amorphous silicon film is 5iHa, B! ) It was formed by glow discharge decomposition of a mixed gas of 16 and h. A p-type amorphous silicon carbide film may be used for this film. Such an n-type Cu1 with a forbidden band width of about IeV and a high absorption coefficient
nSe, in a structure in which a p-type amorphous silicon film with a forbidden band width of 1.8 to 2 eV is stacked on the light incident side of the film to form a heterojunction, since the p-type amorphous silicon film has an amorphous structure, the lattice defect As a result of relaxing constraints on matching and forming a good heterojunction, there is an advantage that high photovoltaic properties can be obtained. For this configuration, AMl
Under room/cd, open circuit voltage v,,0.5v, short circuit current Jsc 23mA/cnl, fill factor FF0.55. A conversion efficiency of 6.3% was obtained. The characteristics of the conventional n CdS/p CuIn5et heterojunction structure are V 6C0,3V, J 3
Since the C23111A/oA, FFO, and conversion efficiency were 2%, the effect of the present invention is clear. Conversely, a similar effect can be obtained by using a p-type CurnSeg and forming a heterojunction with an n-type amorphous silicon film. Cu1
The conductivity type of nSe is n-type when the Cu/In ratio is 0.9 or less, and p-type when it is 1.0 or more. FIG. 2 shows an example in which a glass plate 5 is used as a substrate, and the formation order is reversed from that in FIG. A silicon film 3 is formed to a thickness of 100 to 500 layers. Continued 20
n-type CuInSag l! using a spray method that allows film formation at low temperatures of 0 to 300°C. ! 2 was formed, and finally a metal electrode film 6 of M or the like was formed by vapor deposition. In this case, the light will be incident from the glass side. In this case as well, a combination of the same ts n-type amorphous silicon film and p-type CuIn5et Ill as in the embodiment of FIG. 1 may be used. 3 and 4 show an embodiment of a photovoltaic device having a tandem structure of a p-1-n amorphous silicon cell and a CuTnSez cell. In the case of FIG. 3, the photovoltaic device shown in FIG. After laminating the n-type Cu1nSe4 film 2 and the n-type amorphous silicon film 3 in the same way as in the case of , the n-type, i-type, and n-type amorphous silicon films 7.8.3
are sequentially formed, and a transparent TLL14 is applied thereon. FIG. 4 shows an example of a tandem structure using a glass substrate, in which p-type, i-type, and , n-type amorphous silicon film 3° 8.7° are inserted, forming a tandem structure. With such a tandem structure, the p-1-n amorphous silicon cell first captures 400 to 60% of the solar radiation.
Photoelectric conversion is performed in the optical wavelength region of 0 nm, and then 600 ~
As a result of photoelectric conversion of light in the wavelength range of 11000n using a CuIn5et heterojunction cell, a high-performance photovoltaic bag is produced:
is obtained. Although the embodiment using Cu1nSez as the Cu1nXg semiconductor has been described above, the same film formation method can be used when Cu1nSz is used, and a photovoltaic device with excellent performance can be manufactured.

【Effect of the invention】

According to the present invention, chalcopalite-based Cu1 such as CuInSez or Cu1nS1, which has a high light absorption coefficient,
nχ. Since the heterojunction structure is formed using an amorphous silicon film with well-developed film formation technology, it eliminates the problem of lattice mismatch at the junction and allows photovoltaic power U Tl with good photovoltaic properties to be generated. It can be easily obtained and its effects are extremely large.

[Brief explanation of drawings]

Fig. 1 is a sectional view of one embodiment of the present invention, Fig. 2 is a sectional view of another embodiment, and Figs. 3 and 4 are sectional views showing two different embodiments of the present invention having a tandem structure. be. l: metal substrate, 2: n-type Cu1nSe, film, 3: p-type amorphous silicon film, 4: i3 bright conductive W film, 5: 1,4
Figure 1 Figure 2

Claims (1)

[Claims] 1) It has a heterojunction consisting of a semiconductor film of one conductivity type and an amorphous silicon film of another conductivity type, which has a molecular formula of CuInX_2, where X is a group VI element of the periodic table, and the amorphous silicon side of the junction is the light incident side. A photovoltaic device characterized by: