Monocrystalline silicon solar energy has the highest photoelectric conversion efficiency of 24%, which is the highest among all kinds of solar cells. However, the manufacturing cost of monocrystalline silicon solar cells is so high that it can not be widely used. In terms of production cost, polycrystalline silicon solar cells are cheaper than monocrystalline silicon solar cells, but the photoelectric conversion efficiency of polycrystalline silicon solar cells is much lower. In addition, the service life of polycrystalline silicon solar cells is shorter than monocrystalline silicon solar cells. Therefore, in terms of performance price ratio, monocrystalline silicon solar cells are slightly better.

Researchers have found that some compound semiconductor materials are suitable for solar photovoltaic conversion films. For example, CDs, CdTe; III-V compound semiconductors: GaAs, aipinp, etc; Thin film solar cells made of these semiconductors show good photoelectric conversion efficiency. Semiconductor materials with multiple gradient band gaps can expand the range of solar energy absorption spectrum and improve the photoelectric conversion efficiency. It makes thin-film solar cells have broad prospects for a large number of practical applications. Among these multi-component semiconductor materials, Cu (in, GA) Se2 is a solar light absorbing material with excellent performance. Based on it, thin-film solar cells with significantly higher photoelectric conversion efficiency than silicon can be designed, and the photoelectric conversion rate can reach 18%