Air-Processed and Water-Stable Perovskite Solar Cells Enabled by a Fishing-Net-Inspired Interfacial Network

Practical deployment of perovskite solar cells is hindered by fragile interfaces that accelerate degradation under moisture, heat, ion migration, and mechanical stress, particularly during ambient processing. Here, we introduce a fishing-net-inspired interfacial molecular network that imparts intrinsic durability through coordination chemistry and interfacial dipole engineering. The metal-anchored hierarchical network integrates transition metal nodes, rigid small-molecule frameworks, and dense amine-functionalized polymer sub-networks into a netlike architecture that enhances charge extraction while suppressing bidirectional ion migration. Devices incorporating this interlayer achieve power conversion efficiencies of 26.19% (1.53 eV), 24.11% (1.61 eV), and 20.00% (1.77 eV), with open-circuit voltages and fill factors all exceeding 90% of the Shockley-Queisser radiative limit. Notably, this performance is maintained even in wide-bandgap flexible devices. Flexible perovskite solar cells fabricated entirely under ambient air achieve 23.03% efficiency and retain 95% of their initial performance after 10,000 bending cycles. Moreover, the devices exhibit suppressed degradation during direct water immersion and reach a T95 exceeding 2000 h under ambient conditions without encapsulation, establishing a broadly applicable interfacial design strategy for durable optoelectronics.