PbCl2-assisted film formation for high-efficiency heterojunction perovskite solar cells

Abstract

In this work, PbCl₂ is used as an additive to assist organolead trihalide perovskite film formation in a two-step sequential deposition process. PbCl₂ inhibits PbI₂ crystallization and contributes to the full conversion of PbI₂ and enhanced perovskite film morphology control. Cl⁻ incorporation into the perovskite improves charge transport within the film, as confirmed by the resulting prolonged photoluminescence lifetime observed. A reaction temperature of approximately 50 °C between the PbI₂/PbCl₂ film and CH₃NH₃I isopropanol solution is essential for synthesizing high-performance perovskite solar cells. Addition of PbCl₂ results in a perovskite solar cell energy efficiency of 14% and achieves an average efficiency enhancement of approximately 30% compared with that obtained from the control group.