Synergistic Chemical and Physical Encapsulation Strategies Enable Highly Stable and Lead Leakage-Suppressed Perovskite Solar Cells

Although outstanding power conversion efficiency has been achieved in perovskite solar cells (PSCs), poor stability and lead (Pb) toxicity are still the key challenges limiting the commercial application of PSCs. Herein, we adopted both chemical encapsulation and physical encapsulation to address these problems. Via strong chemical interaction between dibutyl phthalate (DBP) and perovskite, the chemical encapsulation strategy results in higher perovskite film quality with reduced trap density, and the device efficiency enhances from 22.07% to 24.36%. Physical encapsulation polymer with high film robustness and self-healing properties could effectively isolate external risks and restore protection after physical damage. Furthermore, both chemical and physical encapsulation materials could trap Pb ions leaking from the perovskite materials by forming coordination interactions. We simulated realistic scenarios in which PSCs encapsulated by different methods suffered water immersion and mechanical damage, and quantitatively measured Pb leakage rates under different conditions. Higher device stability and greater Pb leakage reduction were achieved, confirming the excellent encapsulation effect of the synergy of chemical and physical encapsulation. This study provides an effective strategy to realize safe and environmentally friendly PSCs to promote their commercialization.