Research progress of light and elevated temperature-induced degradation in silicon solar cells: A review

At present, passivated emitter and rear cell (PERC) solar cells dominate the photovoltaic industry. However, light and elevated temperature-induced degradation (LeTID) is an important issue responsible for the reduction of PERC efficiency, which may lead to up to 16% relative performance losses in multicrystalline silicon solar cells, and this degradation occurs in almost all types of silicon wafers. Even in next-generation silicon solar cells like Tunnelling oxide passivated contact (TOPCon) and Heterojunction with Intrinsic Thin-layer (HJT) solar cells, LeTID can still cause an efficiency loss up to 1% relative. LeTID is a long process in terms of time during the whole cycle of degradation and regeneration, which will seriously affect the conversion efficiency and stability of solar modules, and hence increase the cost of electricity generated by solar cells. Furthermore, after years of research on LeTID, researchers are yet to determine the specific cause of LeTID. In this paper, we refer to specific literature, briefly describe the development history of LeTID, introduce the phenomena of LeTID in crystalline silicon solar cells, and describe its characteristics. In addition, we also analyzed the fundamental causes of LeTID, and found that the cause may be related to metal impurities or hydrogen contained in solar cells. At present, in view of the participation of hydrogen in LeTID and other existing related theories, this paper introduces several methods to inhibit LeTID in crystalline silicon. Finally, the content of this paper is summarized, and the development of solar cells in the future is prospected.