Preventing lead leakage with built-in resin layers for sustainable perovskite solar cells

Lead leakage from damaged perovskite solar modules during rainfall poses a serious threat to the environment and human health. Strategies to replace lead have seen little success to date, while the encapsulation approaches tend to compromise the low-cost advantage of perovskites. Coating lead-adsorbing layers on glass surfaces may help to reduce the risk; however, these layers are vulnerable to either saturation or contamination by rain or dust. Here we report a new device structure that incorporates a low-cost mesoporous sulfonic acid-based lead-adsorbing resin into perovskites as a scaffold, which immobilizes lead ions inside the scaffold even if perovskites are exposed to rainwater. Introducing the insulating scaffold not only does not decrease the device efficiency, but also can be scaled up to large-area modules (60.8 cm2) with an aperture efficiency of 16.3%. This structure proves more effective in preventing lead leakage than the configuration with the coating on the glass surface and is able to reduce the lead contamination of rainwater from damaged perovskite modules to 11.9 parts per billion. This solution addresses the toxicity concern of lead-based perovskites for solar cells and other applications and represents an important step towards sustainability. The presence and leaching of toxic lead in perovskite solar cells form a major environmental concern. Here the authors embed low-cost lead-absorbing resins into the perovskite layers, which reduces the lead leakage to the level of safety without compromising the device performance.