Dual-SAM/Al₂O₃-Nanoparticles Hole-Selective Stack With BCP/PEAI Passivation Enabling High Performance Inverted...

While hole-selective self-assembled monolayers (SAMs) serve as pivotal components for high-performance inverted perovskite solar cells (PSCs), conventional single-layer SAM architectures struggle to reconcile efficient carrier extraction and superior device stability simultaneously. Herein, we rationally design a dual-interface architecture featuring alumina nanoparticles (Al₂O₃-NPs) between two phosphonic acid-based SAMs. The embedded Al₂O₃-NPs not only effectively seal pinholes within the bottom SAM but also construct robust Al-O-P bridging linkages with the upper SAM, enabling a higher effective work function, balanced charge transport, and significantly suppressed non-radiative recombination. In parallel, a BCP/PEAI bilayer overlayer passivates surface defects at the perovskite interface and reinforces electron extraction through favorable π-π stacking interactions. In parallel, a BCP/PEAI bilayer overlayer passivates surface defects at the perovskite interface and reinforces electron extraction through favorable π-π stacking interactions. Consequently, the optimized inverted PSCs yield a champion PCE of 25.13% with a fill factor of 82.6%, accompanied by negligible hysteresis and 73.8% PCE retention after 2700 h of ambient storage. This work provides a dual-interface molecular engineering strategy toward highly efficient and stable perovskite solar cells.