An effective and economical encapsulation method for trapping lead leakage in rigid and flexible perovskite photovoltaics

The potential lead leakage problem of perovskite solar cells poses a severe threat to the ecosystem and human health, which becomes a serious hurdle for the commercialization of this technology. To address this issue, a facile and economical encapsulation process is developed for the first time by employing the mixture of a cation-exchange resin (CER) and an ultraviolet resin as an encapsulant for coating on the metal-side of both rigid and flexible perovskite photovoltaic (PV) devices to effectively capture the leaked Pb²⁺. Consequently, over 90% of Pb²⁺ from the degraded perovskite solar cells and modules can be captured by the encapsulant through an efficient reaction between CER and Pb²⁺ under various conditions that simulate potential severe weather situations (acid rain after hail impact, high humidity). The lead leaching from both rigid and flexible perovskite solar modules could be reduced to < 5 ppm, which can successfully meet the laboratory assessment required for the Resource Conservation and Recovery Act Regulation (RCRA). This work provides an economical and effective strategy to address the toxicity issue of rigid and flexible perovskite PV devices to facilitate their commercialization.