Surface Defect Passivation of All-Inorganic CsPbI2Br Perovskites Via Fluorinated Ionic Liquid for Efficient Outdoor/Indoor Photovoltaics Processed in Ambient Air

•For the first time, we have used CFBA passivation on CsPbI2Br film.•CFBA surface treatment assists to develop highly crystalline and compact film.•CFBA modification significantly reduced the trap-assisted density.•Optimized CFBA based PSC showed an impressive PCE of 17.07%.•A noticeable indoor PCE of 23.24% was found under LED light (3200 K, 1000 lx).