Trapping lead in perovskite solar modules with abundant and low-cost cation-exchange resins

One major concern for the commercialization of perovskite photovoltaic technology is the toxicity of lead from the water-soluble lead halide perovskites that can contaminate the environment. Here, we report an abundant, low-cost and chemically robust cation-exchange resin (CER)-based method that can prevent lead leakage from damaged perovskite solar modules under severe weather conditions. CERs exhibit both high adsorption capacity and high adsorption rate of lead in water due to the high binding energy with lead ions in the mesoporous structure. Integrating CERs with carbon electrodes and layering them on the glass surface of modules has a negligible detrimental effect on device efficiency while reducing lead leakage from perovskite mini-modules by 62-fold to 14.3 ppb in water. The simulated lead leakage from damaged large-area perovskite solar panels treated with CERs can be further reduced to below 7.0 ppb even in the worst-case scenario that every sub-module is damaged. Lead leakage from damaged perovskite photovoltaic modules poses health and environmental risks limiting the potential use of the technology. Now Chen et al. show that the encapsulation of perovskite modules with a cation-exchange resins reduces lead leakage to 14.3 ppb in waste water.