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 (Voc) 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 Vocof 1.68 V, coupled with excellent storage, thermal and operational stability.