Rotatable Skeleton for the Alleviation of Thermally Accumulated Defects in Inorganic Perovskite Solar Cells

The stability of perovskite solar cells has been identified as the bottleneck for their industrialization. With an aim at tackling this challenge, we self-synthesize a thus-far unreported linearly rotatable structure perovskite, i.e., TrMAPbX3 (X = Br, I). The as-prepared hybrid perovskite is observed to demonstrate extremely high stability during device operation with high electric field strength and high temperature, which is associated with the good lattice-matching heterojunction structure between the linearly rotatable TrMAPbX3 structure and 3D inorganic perovskite domain within a wide temperature range. The tight-fitting interface structure is devoted to inhibiting the accumulation of vacancy defects during device operation, which further avoids the δ-phase transition and charge transport resistance. Accordingly, we realize a CsPbI3–xBrx inorganic perovskite-based solar cell with power conversion efficiency (PCE) of 20.59%, extending the remarkably high thermal stability to 192 h (85 °C and relative humidity of 25%) and 3055 h (25 °C and relative humidity of 25%).