Siloxane‐Mediated Dual Cross‐Linking for Thermally Resilient and Efficient Perovskite Solar Cells

ABSTRACT The practical application of perovskite solar cells (PerSCs) is still limited by their intrinsic instability, particularly under dynamic temperature fluctuations in outdoor conditions. In this study, we present a series of dual cross‐linking agents to improve the efficiency and temperature endurance of PerSCs. Specifically, 3‐(trichlorosilyl)propyl methacrylate (MPTCl) with multiple functional groups is applied to modify the upper interface of the perovskite. The ─C═O group exhibits strong interactions with the undercoordinated Pb 2+ on the perovskite surface, helping to stabilize structures and reduce interfacial charge recombination. The C═C bond of the methacrylate group undergoes in situ polymerization/cross‐linking, while the trichlorosilyl group undergoes hydrolysis and subsequent condensation under humid conditions, enabling MPTCl to form a Si─O─Si cross‐linked network. This cross‐linked interfacial layer improves interfacial structural stability and enhances resistance to moisture‐ and heat‐induced degradation. Consequently, the optimal PerSCs achieved a high power conversion efficiency of 26.22% and demonstrated enhanced thermal durability under simulated thermal cycling conditions, retaining 82.4% of their initial efficiency after 250 cycles. This work proposes a dual cross‐linking strategy that provides an effective route for simultaneously improving the efficiency and thermal resilience of PerSCs, offering valuable insights into the development of durable perovskite photovoltaic technologies.