Improving the performance of lead acetate-based perovskite solar cells via solvent vapor annealing

Abstract

Lead acetate-based perovskite solar cells (PSCs) have shown their superiority in terms of controlled grain growth and replacement of traditional lead halides, which is critical for their large-scale commercial applications; however, the lack of control on the grain quality of lead acetate-based perovskite still creates risks such as unwanted defects, pinholes and grain boundaries. Herein, we proposed a reliable method to control the morphology and grain size of lead acetate-based perovskites along with a dynamic solvent-vapor annealing treatment; it was found that the vapors of N,N-dimethylformamide (DMF) assisted in the growth of perovskite grains and facilitated the increase in grain size. Using optimized DMF volume, the fabricated planar PSCs with the structure FTO/TiO₂/perovskite/spiro-OMeTAD/Ag achieved the highest power conversion efficiency (PCE) of 13.71%, which was 23.8% higher than that of the controlled device. Moreover, the hysteresis effect was negligible. The results demonstrate that the solvent vapor-assisted crystal growth process is a simple and facile way to improve the quality of lead acetate-based perovskites and increase their performance.