“…[8] Aiming for improved stability,all-inorganic (CsPbX 3 , X = I À ,B r À ,o rC l À )p erovskites free of volatile components by replacing the organic MA + or FA + species with inorganic Cs + have been widely studied for alternative light absorbers. [9,10] Among them, tri-brominated CsPbBr 3 shows superior environmental tolerance even in 90 %h umidity,b ut their photovoltaic performances are still sluggish owing to the substantial charge losses and dilatory photogenerated charge diffusion. [11,12] Although the energy band engineering is prevalent to accelerate charge separation, [13] the state-ofthe-art hole transporting materials (HTMs) are generally organic species,s uch as spiro-MeOTAD, PTAA, or P3HT, which will introduce new hazards (hygroscopic additives,o r light/thermal instability) and subsequently degrade the cell efficiency, [14,15] against the establishment of all-inorganic PSCs.T herefore,h ow to promote the charge separation without sacrificing the excellent stability is an urgent projection for further PSC platforms.…”