Advances in Phase Stability of Cesium Lead Halide Perovskites

摘要

Cesium lead halide (CsPbX_3) perovskite solar cells have gained considerableattention for their rapid evolution to over 19% power conversion efficiency.Despite high chemical stability, the spontaneous phase transition from desiredblack phase to nonperovskite yellow phase after long-time storage or under attackof extrinsic factors significantly hinders their development and application. Thisreview summarizes the current advances in recognizing phase transitionbehaviors of cesium lead halides, especially cesium lead tri-iodide, andaddressing phase instability issues. Advancing strategies that are used for phasestabilization, including compositional engineering, grain size reduction, modificationof surface termination, and strain engineering, are highlighted as well astheir present limitations. Also, existing scientific debates on phase transition andstability, origin of these arguments, and possible solutions are presented anddiscussed. Finally, some potential avenues for further enhancing stability ofcesium lead halides are proposed based on current understandings.