Facile Recovery of Lead in Discarded Perovskite Solar Cells via Ultrasonic Water Leaching

Perovskite solar cells (PSCs) stand at the forefront of advanced optoelectronic devices because of their high theoretical power conversion efficiency, cost-effectiveness, and broad application potential. However, as a crucial component in high-performance PSCs, highly toxic lead may leak from discarded PSCs and cause environmental and health risks. Implementing the effective recovery of lead from discarded PSCs is crucial for the sustainable development of the PSC industry. Existing lead recovery methods commonly use toxic organic solvents as leaching reagents, i.e., dimethyl formamide and dimethyl sulfoxide, impeding the potential application of recycling technologies. This study proposes a facile ultrasonic water leaching technique for effectively recovering lead from the glass substrate of discarded PSCs. During the ultrasonic water leaching process, the perovskite layer undergoes rapid degradation, generating PbI2. Most of the PbI2 dissolves in the water, yielding a leaching solution containing a low lead concentration, while a minor fraction is converted into insoluble Pb(OH)I particles. The cumulative Pb removal ratio from the first two cycles of ultrasonic water leaching processes can reach 99.84%. High-purity (>99.9 wt %) PbI2 crystals could be synthesized through an evaporation–crystallization step. This study proposes a vital strategy for the sustainable management of discarded perovskite photovoltaic devices without the addition of any organic solvents.