Probing the Intrinsic Thermal and Photochemical Stability of Hybrid and Inorganic Lead Halide Perovskites

We report a careful and systematic study of thermal and photochemical degradation of a series of complex haloplumbates APbX₃ (X = I, Br) with hybrid organic (A⁺ = CH₃NH₃) and inorganic (A⁺ = Cs⁺) cations under anoxic conditions (i.e., without exposure to oxygen and moisture by testing in an inert glovebox environment). We show that the most common hybrid materials (e.g., MAPbI₃) are intrinsically unstable with respect to the heat- and light-induced stress and, therefore, can hardly sustain the real solar cell operation conditions. On the contrary, the cesium-based all-inorganic complex lead halides revealed far superior stability and, therefore, provide an impetus for creation of highly efficient and stable perovskite solar cells that can potentially achieve pragmatic operational benchmarks.