Low‐Temperature Encapsulation with Silicone Grease Enhances Efficiency and Stability of Perovskite Solar Cells via Pb⁰ Defect Passivation

Abstract Encapsulation is a critical strategy for mitigating the instability of perovskites, which remains the primary challenge for their commercialization. Traditional encapsulation adhesives, such as ethylene vinyl acetate and epoxy resin, are constrained by high‐temperature processes and potential chemical reactions that can impair the efficiency of perovskite devices. The use of vacuum silicone grease, primarily composed of polydimethylsiloxane (PDMS), not only shields the perovskite devices from moisture and oxygen but also significantly enhances their power conversion efficiency from 23.91% to 25.34%. Further investigations reveal that this improvement can be attributed to the formation of coordination bonds between the oxygen atoms in PDMS and lead within the perovskite structure. This mechanism boosts efficiency and inhibits the formation of Pb 0 defects, significantly contributing to efficiency loss and instability. A ten‐fold increase in stability is observed at ≈90% humidity, underscoring its potential as a low‐temperature, non‐damaging, and effective encapsulation method for enhancing the stability and performance of perovskite solar cells.