Lead Leaching of Perovskite Solar Cells in Aqueous Environments: A Quantitative Investigation

Abstract

Lead halide perovskite solar cells (PSCs) have emerged as a highly promising next-generation photovoltaic (PV) technology that combines high device performance with ease of processing and low cost. However, the potential leaching of lead is recognized as a major environmental concern for their large-scale commercialization, especially for application areas with significant overlap with human life. Herein, a quantitative kinetic analysis of the Pb leaching behavior of five types of benchmark PSCs, namely, MAPbI3, FA0.95MA0.05Pb(I0.95Br0.05)3, Cs0.05(FA0.85MA0.15)0.95Pb(I0.85Br0.15)3, CsPbI3, and CsPbI2Br, under laboratory rainfall conditions is reported. Strikingly, over 60% of the Pb contained in the unencapsulated perovskite devices is leached within the first 120 s under rainfall exposure, suggesting that very rapid leaching of Pb can occur when indoor and outdoor PV devices are subject to physical damage or failed encapsulation. The initial Pb leaching rate is found to be strongly dependent on the types of PSCs, pointing to a potential route toward Pb leaching reduction through further optimization of their materials design. The findings offer kinetic insights into the Pb leaching behavior of PSCs upon aqueous exposure, highlighting the urgency to develop robust mitigation methods to avoid a potentially catastrophic impact on the environment for their large-scale deployment.