• • SiO2/2PACz composite interface achieves PCE of 20.14% (rigid) and 19.30% (flexible), with flexible devices retaining >90% initial efficiency after repeated bending, demonstrating a viable route to mechanically robust flexible OSCs.
• • SiO2 nanoparticles outperform NiOx counterparts by avoiding aggregation and parasitic absorption, ensuring optical transparency and structural compatibility, which is critical for maintaining high photocurrent in ultrathin interlayers.
• • Dynamic hydrogen bonding between SiO2 and phosphonic acid groups of 2PACz enables efficient energy dissipation during cyclic deformation, directly addressing the mechanical fragility of SAMs.
• • Interfacial polarity modulation extends the crystallization time window of the active layer, enhancing molecular ordering and charge transport, which underpins the simultaneous improvement in efficiency and stability.