Stabilizing Solution and Solid Phased Perovskite Towards High Performance Photovoltaic Devices with Superior Batch Stability and Consistency

Fabricating high-performance perovskite solar cells (PSCs) with solution processing is conducive to low-cost commercial production, it is therefore rather critical to stabilize perovskite in both solution and solid phases. For this purpose, the speed-up ageing of perovskite solution in air was systematically studied and its severe spontaneous degradation was observed. To address this issue, we introduce 4-(trifluoromethyl)phenylhydrazine (TFPH) to modify the perovskite solution, which presented enhanced storage stability. Consequently, when the modified solution was used to prepare PSCs, we obtained much improved and well consistent power conversion efficiencies (PCEs, ~ 26.0%) regardless of the perovskite solution ageing time, as well as excellent operational stability, which maintains PCE ≥ 92% for 1830 hours. These remarkable results are attributed to the multiple functions of TFPH: a) inhibiting the degradation of perovskite; b) favoring the oriented crystallization; c) reducing trapping density, etc. This work substantially assists understanding and modification to perovskite degradation in both solution and solid phases. The excellent performance stability and consistency on the TFPH modified device batches is of great significance for commercial production of PSCs.