CIGS Solar Cell - The Development of Cd-Free Buffer Layer Materials and Process Technology

摘要

The development of Cd-free buffer layer is one of the most important topics for the evolution of CIGS solar cell. Nowadays, the CdS is typically used as buffer layer in high efficiency CIGS solar cell. However, Cd is very toxic and makes great impact to our environment. To reduce the usage of Cd and keep the high efficiency of CIGS solar cell for the commercializing demand, a lot of effort has been done for the exploration of Cd-free buffer layer. In this article, we introduced the main functions of buffer layer in CIGS solar cell and the technological challenges on buffer layer deposition for mass production. Three potential candidate ZnS, In_2S_3 and Zn_(1-x)Mg_xO to replace the CdS buffer layer and their corresponding deposition technologies such as sputter, evaporation and ALD were discussed.