Thermodynamically Self‐Healing 1D–3D Hybrid Perovskite Solar Cells

Thermal degradation in perovskite solar cells is still an unsettled issue that limits its further development. In this study, 2‐(1H‐pyrazol‐1‐yl)pyridine is introduced into lead halide 3D perovskites, which allows 1D–3D hybrid perovskite materials to be obtained. The heterostructural 1D–3D perovskites are proved to be capable of remarkably prolonging the photoluminescence decay lifetime and suppressing charge carrier recombination in comparison to conventional 3D perovskites. The intrinsic properties of thermodynamically stable yet kinetically labile 1D materials allow the system to alleviate the lattice mismatch and passivate the interface traps of heterojunction region of 1D–3D hybrid perovskites that may occur during the crystal growth process. Importantly, the as‐fabricated 1D–3D perovskite solar cells display a thermodynamic self‐healing ability, which is induced through blocking the ion‐migration channels of A‐site ions by the flexible 1D perovskite with less densely close‐packed structure. Particularly, the power conversion efficiency of as‐fabricated unencapsulated 1D–3D perovskite solar cells is demonstrated to be reversible under temperature cycling (25–85 °C) at 55% relative humidity, which largely outperforms the pure 3D perovskite solar cell. The present study provides a facile approach to fabricate 1D–3D perovskite solar cells with high efficiency and long‐term stability.