Tailoring type-II all-in-one buried interface for 1.635V-voltage, all-inorganic CsPbBr3 perovskite solar cells

Abstract

Precise manipulation on buried interface of perovskite film highly determines the photovoltaic performance of perovskite solar cells (PSCs). Herein, we demonstrate a SnO2-SnS2 heterojunction nanocrystal as an efficient electron transfer material to heal the defective interface for planar all-inorganic CsPbBr3 PSCs. Arising from the matched lattice distance of SnS2 with SnO2 and CsPbBr3, an all-in-one SnO2-SnS2-CsPbBr3 interface is fabricated, in which SnS2 plays a role of “bridge” to connect incompatible interface. Consequently, the charge recombination loss is minimized owing to the Type-II band alignment and epitaxial growth induced defect reduction, achieving a remarkable efficiency of 10.72% with a high open-circuit voltage of 1.635V. Considering the high tolerance to high humidity (80%) for 700 h and high temperature (80 °C) over 30 days, these preliminary results can provide a new perspective for the rational design of ideal charge transfer materials to improve the efficiency and stability of PSCs.