Enhancing Efficiency and Stability of Perovskite Solar Cells via Photosensitive Molecule-Assisted Defect Passivation

High-quality defect-free perovskite films exhibiting improved surface morphology are required for constructing highly efficient perovskite solar cells (PSCs). Incorporation of appropriate passivation molecules in perovskite films is a popular strategy to achieve this goal. Herein, the defect passivation effect of a series of photosensitive benzoyl derivatives on the perovskite layer is investigated through the comprehensive analysis of perovskite film and corresponding solar cells. Photosensitive molecules introduced with carbonyl groups considerably diminish the defects of Pb2+ and MA+ by forming either coordinate bonds or hydrogen bonds. The ultraviolet (UV) photoinitiation properties of benzoyl derivatives help sufficiently restrain the photodegradation of perovskites during device operation. In addition, photosensitive molecule-assisted passivation strategy effectively inhibits unwanted defect-assisted recombination, improving the power conversion efficiency (PCE) from 16.94% to 19.64%. Meanwhile, passivated devices exhibit considerably enhanced light stability, with >80% of the initial PCE maintained under continuous 1 sun illumination for 700 h. This approach aids in fabricating defect-free and UV-resistant perovskite-based photoactive layers for highly efficient and stable PSCs.