Improving intrinsic stability for perovskite/silicon tandem solar cells

Monolithic hybrid halide perovskite/crystalline silicon (c-Si) tandem solar cells have demonstrated their great potential to surpass the theoretical efficiency limit of single-junction devices. However, the stability of perovskite sub-cells is inferior to that of the c-Si solar cells that have been commercialized, casting serious doubt about the lifetime of the entire device. During device operation, light and heat are inevitable, which requires special attention. Herein, we review the current understandings of the intrinsic stability of perovskite/c-Si tandems upon light and/or heat aging. First, we summarize the recent understandings regarding light facilitated ion migration, materials decomposition, and phase segregation. In addition, the reverse bias effect on the stability of tandem modules caused by uneven illumination is discussed. Second, this review also summarizes the thermal-induced degradation and mismatch issue, which underlines the system design of perovskite/c-Si tandems. Third, recent strategies to improve the intrinsic stability of perovskite/c-Si tandems under light and/or heat are reviewed, such as composition engineering, crystallinity enhancement, interface modification, material optimization, and device structure modification. At last, we present several potential research directions that have been overlooked, and hope those are helpful for future research on perovskite based tandem solar cells.