Improving perovskite solar cell performance utilizing cystamine dihydrochloride for passivating defects

The quality of perovskite crystal plays a crucial role in enhancing the photoelectrical performance of perovskite solar cells (PSCs). Aiming at the excess PbI2 defects in the perovskite films during the perovskite crystal growth process, this work reports a simple and effective way for improvement of perovskite films through suppressing the formation of excess PbI2 and surface defects passivation. The introduction of cystamine dihydrochloride (CMDR) with double amino groups into the perovskite precursor can consume I- ions and passivate the PbI2 defects. Thus a high quality perovskite film with reduced grain boundaries and inhibited carrier recombination is constructed. The CMDR-based champion device achieves a power conversion efficiency (PCE) of 20.26% with excellent stability, which can be attributed to the positive effect of the formed high quality perovskite film.