Heterointerfacial Bonding Governs Service Stability in Flexible Perovskite Photovoltaics

The service stability of flexible perovskite solar module (FPSM) is contingent upon the bonding strength and stress-response behavior at heterointerfaces. However, the fullerene-based layer mainly relies on weak non-covalent interactions. This makes it difficult for the FPSM to tackle the challenges posed by the coupling of multiple stresses in the actual service environment. Through the blending strategy of the polyamide curing agent and fullerene derivatives, we constructed an active energy-dissipating multi-bond network featuring covalent bond anchoring and hydrogen bond dissipation, which significantly enhanced the interfacial bonding and energy dissipation capabilities. Based on this strategy, a 100 cm² FPSM achieves a recorded power conversion efficiency of 22.33% (certified 21.5%). More importantly, for the first time, we developed an in situ bending electroluminescence experiment for FPSM under ultraviolet irradiation. After 5000 consecutive bending cycles, there was no significant decline in the module's performance, which verified its service stability under multi-field coupling.