All inorganic CsPbI3 perovskite solar cells with reduced mobile ion concentration and film stress

Here, we study the impact of a polyvinylpyrrolidone (PVP) additive on cesium-based lead halide perovskites. We demonstrate the control of phase, morphology, film stress, and ion concentration under accelerated aging with the use of PVP in CsPbI3. The addition of PVP in all-inorganic metal halide perovskites (MHP) further induces a residual compressive film stress, a factor that is correlated with improved film stability. The removal of PVP increased the stress based on a contraction in the film. Under thermal cycling, thermal aging, and light-induced aging, all-inorganic MHP films experienced negligible bandgap change and comparable ion behavior with and without PVP removal.