Incorporating CsF into the PbI_2 Film for Stable Mixed Cation-Halide Perovskite Solar Cells

摘要

Adding a small amount of CsI into mixed cation-halide perovskite film via a one-step method has been demonstrated as an excellent strategy for high-performance perovskite solar cells (PSCs). However, the one-step method generally relies on an antisolvent washing process, which is hard to control and not suitable for fabricating large-area devices. Here, CsF is employed and Cs is incorporated into perovskite film via a two-step method. It is revealed that CsF can effectively diffuse into the PbI2 seed film, and drastically enhances perovskite crystallization, leading to high-quality Cs-doped perovskite film with a very long photoluminescence carrier lifetime (1413 ns), remarkable light stability, thermal stability, and humidity stability. The fabricated PSCs show power conversion efficiency (PCE) of over 21%, and they are highly thermally stable: in the aging test at 60 degrees C for 300 h, 96% of the original PCE remains. The CsF incorporation process provides a new avenue for stable high-performance PSCs.