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

Abstract

Harmful reactions and lattice stress at the NiO_x/perovskite interface are significant challenges that limit the efficiency of NiO_x-based inverted perovskite solar cells. In this study, the surfactant 3-(N,N-dimethyldodecylammonio)propanesulfonate (SB12-3) was introduced between the NiO_x hole transport layer and the perovskite. The sulfonic acid group in SB12-3 effectively passivated the surface defects of NiO_x, enhancing carrier extraction capabilities. Additionally, the long and flexible alkyl chain in SB12-3 significantly alleviated the tensile stress at the NiO_x/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 °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.