Molecularly guided buried-interface regulation for efficient and stable inverted perovskite solar cells

Abstract

Inverted perovskite solar cells (IPSCs) are among the most promising candidates for scalable photovoltaics, yet their buried interfaces remain a critical bottleneck that limits efficiency and long-term stability. In particular, the widespread use of aluminium oxide (Al₂O₃) nanoparticles as porous insulator contacts is hampered by severe aggregation, which obstructs charge transport and undermines perovskite crystallisation. Here, we establish a molecularly guided buried-interface engineering strategy by introducing 2-aminothiazole hydrochloride (2-ATCl) to stabilise and functionalize Al₂O₃ nanoparticles. This multifunctional molecule simultaneously prevents nanoparticle aggregation, enhances the hydrophilicity of self-assembled monolayers, releases lattice strain, and chemically passivates interfacial defects. The resulting devices deliver a power conversion efficiency (PCE) of 26.63% (certified 26.42%), alongside exceptional durability, retaining 90% of the initial performance after 2000 h of storage and 80% after 1000 h of continuous operation without encapsulation. Beyond conventional single-junction cells, this strategy also boosts the performance of wide-bandgap devices and proves compatible with diverse hole-selective monolayers, demonstrating its versatility. Our results present a generalizable molecular design principle for buried interfaces, paving the way towards efficient and durable perovskite photovoltaics.