Enhancing the efficiency and stability of inverted perovskite solar cells through a dual passivation strategy

Abstract Perovskite solar cells (PSCs) continue to be constrained by interfacial defects and trap-assisted nonradiative recombination, which hinder further improvements in power conversion efficiency (PCE) and long-term operational stability. To address these challenges, we propose a synergistic dual-passivation strategy that simultaneously incorporates phenethylammonium iodide (PEAI) and 1,3-diaminopropane dihydroiodide (PDADI) onto the surface of perovskite films. This approach effectively suppresses interfacial defects, enhances crystal quality, and modulates interfacial charge dynamics at the perovskite/electron transport layer interface. The dual-passivated perovskite films exhibit significantly improved morphology and crystallinity, with grain sizes increasing from 228.64 nm to 355.19 nm, trap-state density decreasing from 1.00 × 10 16 cm −3 to 8.27 × 10 15 cm −3 , and average carrier lifetime extending from 323.42 ns to 775.41 ns. Consequently, inverted PSCs based on this treatment display reduced dark current density, enhanced radiative recombination, and achieve a champion PCE of 21.72% (average 20.63%), with a high fill factor of 82.3%. Moreover, unencapsulated devices retain 93% of their initial efficiency after 547 h of ambient storage, outperforming control devices. These results demonstrate that PEAI-PDADI synergistic passivation provides an effective and generalizable pathway toward efficient and stable inverted PSCs.