Surface engineering to mitigate compressive stress and detrimental reactions in NiOx-based inverted perovskite solar cells

Harmful reactions and lattice stress at the NiOx/perovskite interface are significant challenges that limit the efficiency of NiOx-based inverted perovskite solar cells. In this study, the surfactant 3-(N,N-dimethyldodecylammonio)propanesulfonate (SB12-3) was introduced between the NiOx hole transport layer and the perovskite. The sulfonic acid group in SB12-3 effectively passivated the surface defects of NiOx, enhancing carrier extraction capabilities. Additionally, the long and flexible alkyl chain in SB12-3 significantly alleviated the tensile stress at the NiOx/perovskite interface. By combining surface passivation and stress relief, a power conversion efficiency (PCE) of 18.92% was obtained. Unencapsulated devices stored in a N2 atmosphere at 25 degrees C for 1500 h maintained 100% of the initial PCE and those kept in an air environment with a relative humidity of 30-50% retained over 80% of their initial PCE after more than 1000 h.