Xanthate-induced sulfur doped all-inorganic perovskite with superior phase stability and enhanced performance

Abstract Although the efficiency of perovskite-based solar cell has boosted up to 23%, their stability hinders the further development due to the volatile nature of organic components in conventional organic-inorganic hybrid perovskites. All-inorganic perovskites have been reported to achieve enhanced thermal stability. Herein we applied xanthate in all-inorganic perovskite to realize the sulfur-doped CsPbIBr 2 for superior phase stability. The additive cesium xanthate (CsXth) could be decomposed into cesium sulfides during annealing process. The divalent S 2- lies in the interstices of perovskite lattice and strongly coordinates with CsPbIBr 2 to stabilize the ɑ-phase, as a result, greatly enhanced stability was achieved at ambient air with 65% relative humidity (RH) compared with the reference film. Moreover, we obtained a champion efficiency of 9.78% with a high open-circuit voltage (V oc ) of 1.30 V based on 5% CsXth-CsPbIBr 2 under humid air. Performance of sulfur-doped perovskite device shows almost no decay in 10 h under humid air with 65% RH without encapsulation. These advantages provide an efficient way to prepare more efficient and superior stable perovskite device, which is beneficial toward commercialization in the future.