CuBr2-mediated anion-cation co-passivation for enhanced perovskite solar cells

CuBr 2 serves as a dual-functional additive to realize anion-cation co-passivation for perovskite defects. • CuBr 2 modification boosts crystallinity, increases grain size, and suppresses non-radiative recombination in perovskite films. • The optimized device yields enhanced efficiency, reduced hysteresis, and improved stability. Perovskite solar cells (PSCs) are a promising photovoltaic technology, characterized by high efficiency, low cost, and simple solution fabrication. However, the defects at grain boundaries impair optoelectronic performance and degrade long-term operational stability of PSCs. Herein, CuBr 2 additive was incorporated into the perovskite precursor solution, enabling Cu 2+ and Br⁻ to co-passivate iodine vacancies and uncoordinated Pb 2+ . The CuBr 2 -mediated perovskite films demonstrated the optimized crystallinity, facilitated interfacial carrier transportation, and diminished trap concentration. The PSCs achieved an improved efficiency from 18.53% to 20.10% and demonstrated significantly improved long-term environmental stability. This work provides a novel strategy for anion-cation co-passivation of defects in PSCs. Download: Download high-res image (181KB) Download: Download full-size image CuBr 2 was incorporated as a additive to passivate iodine vacancies and uncoordinated Pb 2+ defects in perovskite films, leading to the enhanced crystallinity and improved charge transfer. The efficiency of perovskite solar cells was improved from 18.53% to 20.10%, accompanied by enhanced stability.