Wettability Sequence Optimization and Interface Strain Buffering in Triple Mesoporous Layer‐Based Printable Perovskite Solar Cells for Enhanced Performance

Abstract Perovskite solar cells have achieved remarkable progress in photovoltaic performance, driven by advancements in interface engineering. The buried interface between the electron transport layer and the perovskite layer is particularly critical, as it governs both perovskite crystallization and the formation of residual strain. In this study, the buried interface in printable mesoscopic perovskite solar cells (p‐MPSCs) based on a triple‐mesoporous scaffold of TiO2/ZrO2/carbon is reconstructed by employing dodecaethylene glycol (DEG), a long chain molecule rich in polar oxygen atoms, to enhance device performance. Treating the scaffold with DEG optimizes the wettability sequence across the three layers by improving the TiO2 surface's wettability, facilitating the preferential crystallization of perovskite in the underlying TiO2 layer. Moreover, the DEG layer effectively buffers residual strain and suppresses detrimental defects at the interface. As a result, p‐MPSCs with the optimized interface achieve a power conversion efficiency (PCE) of 20.27% and retain over 92% of their initial PCE after 500 h of continuous operation under maximum power point tracking.