Uncovering the Mechanism Behind the Improved Stability of 2D Organic–Inorganic Hybrid Perovskites

Abstract 2D organic–inorganic hybrid perovskites (OIHPs) may resolve the stability problem of bulk OIHPs. First‐principles calculations are employed to investigate the mechanism behind their favorable material properties. Two processes are identified to play a critical role: First, the 2D structure supports additional distortions that enhance the intrinsic structural stability. Second, the surface terminations of 2D OIHPs suppress degradation effects due to humidity. Having uncovered the stabilization mechanism, 2D OIHPs are designed with optimal stability and favorable electronic properties.