Suppression of Nonradiative Recombination by Vacuum-Assisted Process for Efficient Lead-Free Tin Perovskite Solar Cells

Power conversion efficiency (PCE) of lead (Pb)-free tin (Sn)-based perovskite solar cells (PVSCs) is much lower than that of their Pb-based counterparts, which is mainly attributed to large open-circuit voltage (V-OC) loss and poor fill factor (FF). In this work, a strategy via vacuum-assisted treatment of the Sn perovskite layer to self-heal defects in Sn perovskite is reported, leading to suppression of nonradiative recombination and enhancement of carrier transport capability. Using this method, a maximum PCE of 10.3% is obtained for dual FA-MA (MA = methylammonium and FA = formamidinium) cation Sn-based PVSCs with an improved V-OC of 0.631 V and FF of 75.5%. This work suggests a facile approach to finely inhibit the defects in the bulk or at interfaces for Sn-based devices and further facilitate development of highly efficient Sn-based PVSCs.

Automated summary

The study reports a strategy of vacuum-assisted treatment of the Sn perovskite layer to self-heal defects in Sn perovskite, resulting in improved PCE, V-OC, and FF of Sn-based PVSCs. This work suggests a facile approach to inhibit defects in Sn-based devices, promoting the development of highly efficient Sn-based PVSCs.