Anionic surfactant anchoring enables 23.4% efficient and stable perovskite solar cells

Nonradiative recombination losses at defects in metal halide perovskite films are responsible for hindering the improvement of the photovoltaic performance and stability of perovskite solar cells (PSCs). Here, we report a feasible multifunctional additive strategy that uses cesium stearate to passivate defects in perovskite films and simultaneously enhances the tolerance to light and moisture stress. Nonradiative recombination losses are effectively suppressed in target films that exhibit improved crystallinity, low trap-state density, and enhanced carrier separation and transportation. The present strategy hence boosts the power conversion efficiency of the p-i-n structured PSC to 23.41%. Our device also shows good stability in ambient air without encapsulation, maintaining 91.6% of the initial efficiency after 720 h.