Wide bandgap interface layer induced stabilized perovskite/silicon tandem solar cells with stability over ten thousand hours

The perovskite/silicon tandem solar cell (PK/c-Si TSC) is a reasonable choice that can break through the efficiency limitations of silicon cells. Here, the p-i-n perovskite solar cell is conformally grown by the evaporation–solution combination technique on fully-textured silicon heterojunction cells to realize two-terminal PK/c-Si TSCs. Due to the adverse effect of the residual PbI${}_2$ at the bottom of the perovskite bulk on device performance, a thermal-evaporated CsBr thin layer is introduced between the perovskite layer and the hole transport layer to construct a gradient perovskite absorber for optimized energy level alignment, so as to improve the open-circuit voltage and fill factor of the device. Finally, the PK/c-Si tandem cell achieves an efficiency of 27.48% and is stable in nitrogen over 10 000 h. (© 2021 Wiley-VCH GmbH)