Tailored buried layer passivation toward high-efficiency carbon based all-inorganic CsPbBr₃ perovskite solar cell

The inferior crystallinity and surface defects have significantly hampered the efficiency and open-circuit voltage (V_oc) of CsPbBr₃ perovskite solar cells (PSCs). Herein, we present a buried layer passivated technique by doping CsCl into the SnO₂ precursor. The Cl-terminated SnO₂ film could effectively order the distorted PbBr₂ octahedron, resulting in the improved CsPbBr₃ film and the better energy alignment. Arising from the better energy alignment, the CsCl-SnO₂ nanocomposites repair the defective interface and suppress defects existed at grain boundaries. Significantly, buried layer passivation could relieve lattice strain and promote grain growth due to the strong interface electronic coupling between Pb-Cl atoms. Finally, the champion devices achieve an efficiency of 11.16 % with a record V_oc of 1.68 V, coupled with excellent storage, thermal and operational stability.