Perovskite Quantum Dot Solar Cells Fabricated from Recycled Lead-Acid Battery Waste

A cost-effective and environmentally friendly Pb source is a prerequisite for achieving large-scale, low-cost perovskite photovoltaic devices. Currently, the commonly used method to prepare the lead source is based on a fire smelting process, requiring a high temperature of more than 1000 °C, which results in environmental pollution. Spent car lead acid batteries are an environmentally hazardous waste; however, they can alternatively serve as an abundant and inexpensive Pb source. Due to “self-purification”, quantum dots feature a high tolerance of impurities in the precursor since the impurities tend to be expelled from the small crystalline cores during colloidal nucleation. Herein, PbI₂ recycled from spent lead acid batteries via a facile low-temperature solution process is used to synthesize CsPbI₃ quantum dots, which simultaneously brings multiple benefits including (1) avoiding pollution originating from the fire smelting process; (2) recycling the Pb waste from batteries; and (3) synthesizing high-quality quantum dots. The resulting CsPbI₃ quantum dots have photophysical properties such as PLQY and carrier lifetimes on par with those synthesized from the commercial PbI₂ due to expelling of the impurity Na atoms. The resulting solar cells deliver comparable power conversion efficiencies: 14.0% for the cells fabricated using recycled PbI₂ and 14.7% for the cells constructed using commercial PbI₂. This work paves a new and feasible path to applying recycled Pb sources in perovskite photovoltaics.