Solar cells can convert light energy into electric energy and provide power in an environmentally friendly way. It can be seen that solar cells have a strong sense of use. In order to improve the understanding of solar cells, the classification of solar cells is introduced. If you are interested in solar cells, please read on.
1. First
Solar cells can be divided into crystalline film type and amorphous film type (hereinafter referred to as a -) according to the crystalline state. The former can be divided into single crystal and polycrystalline.
According to different materials, it can be divided into silicon film shape, compound semiconductor film shape and organic film shape. The compound semiconductor film shape can be divided into amorphous shape (a-Si: H, a-Si: H: F, a-SixGel-x: H, etc.), IIV family (GaAs, InP, etc.), IVI family (Cds system), zinc phosphide (Zn3p2), etc.
According to the different materials used, solar cells can also be divided into silicon solar cells, multi-component thin film solar cells, polymer multilayer modified electrode solar cells, nanocrystalline solar cells, organic solar cells, and plastic solar cells. Among them, silicon solar cells are the most mature and advantageous.
2. Silicon solar energy
Silicon solar cells include monocrystalline silicon solar cells, polycrystalline silicon thin film solar cells and amorphous silicon thin film solar cells.
Monocrystalline silicon solar cells have the highest conversion efficiency and the most mature technology. The maximum conversion efficiency of the laboratory is 24.7%, and the batch production efficiency is 15% (18% as of 2011). Although it still plays a leading role in large-scale application and industrial production, the cost of monocrystalline silicon is high, and it is difficult to significantly reduce the cost. In order to save silicon materials, polycrystalline silicon films and amorphous silicon films have been developed as substitutes for monocrystalline silicon solar cells.
Compared with monocrystalline silicon, polycrystalline silicon thin film solar cells have lower cost and higher efficiency than amorphous silicon thin film solar cells. The maximum conversion efficiency of the laboratory is 18%, and the conversion efficiency of industrial scale production is 10% (17% as of 2011). Therefore, polycrystalline silicon thin film batteries will soon dominate the solar cell market.
Amorphous silicon thin film solar cells have the advantages of low cost, light weight, high conversion efficiency, convenient for large-scale production and great potential. However, due to the degradation effect of the photoelectric efficiency of the material, its stability is not high, which directly affects its practicality. If we can further solve the stability problem and improve the conversion rate, amorphous silicon solar cells will become one of the main development products of solar cells.
3. Polycrystalline film
Polycrystalline silicon thin film cells cadmium sulfide and cadmium telluride polycrystalline silicon thin film cells have higher efficiency than amorphous silicon thin film solar cells, lower cost than monocrystalline silicon solar cells, and are easy to mass produce. However, cadmium is highly toxic and will cause serious environmental pollution. Therefore, it is not the best substitute for crystalline silicon solar cells.
The conversion efficiency of GaAs III-V compound battery can reach 28%. GaAs compound materials have very ideal optical band gap and high absorption efficiency. It is highly radioactive and insensitive to heat. It is applicable to the production of high-efficiency single junction batteries. However, the price of GaAs materials is not cheap, which greatly limits the popularity of GaAs batteries.
Copper indium selenium thin film battery (CIS) is suitable for photoelectric conversion, without photo induced attenuation problem, and the conversion efficiency is the same as that of polycrystalline silicon. It has the advantages of low price, good performance and simple technology, and will become an important direction of the development of solar cells in the future. The only problem is the source of the material. Indium and selenium are relatively rare elements, so the development of the battery is bound to be limited.
4. Organic polymer
Substituting organic polymers for inorganic materials is a nascent research field in solar cell manufacturing. Due to the advantages of flexible organic materials, easy production, wide source of materials and low cost, it is of great significance for the large-scale utilization of solar energy and the provision of cheap electricity. However, the research of solar cells made from organic materials has just begun, and neither the service life nor the cell efficiency can be compared with inorganic materials, especially silicon cells. Whether it can be developed into a product with practical significance remains to be further studied and explored.
5、 Nanocrystal
Nanocrystalline chemical energy solar cells are newly developed, which have the advantages of low cost, simple process and stable performance. Its photoelectric efficiency is stable above 10%, and its manufacturing cost is only 1/5~1/10 of that of silicon solar cells. The service life can reach more than 20 years.
The research and development of this battery has just started and will enter the market in the near future.
6、 Organic film
Organic thin film solar cell is a kind of solar cell which is composed of organic materials. It is natural that people are not familiar with organic solar cells. At present, more than 95% of the mass produced solar cells are silicon based, and the remaining less than 5% are also made of other inorganic materials.
7、 Dye sensitization
The dye sensitized solar cell makes the dye attach to TiO2 particles and soak in the electrolyte. Pigments are irradiated by light and generate free electrons and holes. Free electrons are absorbed by TiO2, flow out of the electrode to the external circuit, pass through the electrical appliance, flow into the electrolyte, and finally return to the pigment. Dye sensitized solar cells have low manufacturing cost and strong competitiveness. Its energy conversion efficiency is about 12%.
8、 Plastic battery
Plastic solar cells are made of recyclable plastic film, which can be produced in large scale through “roll to roll printing” technology, with low cost and environmental protection. However, plastic solar cells are not yet mature. It is expected that the manufacturing technology of solar cells based on plastic and other organic materials will be mature and widely used in the next 5 to 10 years.
