Surface Chemistry of Solution-Grown CsPbBr₃ Single Crystals and Their Selective Cleaning for Linear-Responsive X-ray Detectors

Surface contamination challenges solution-grown perovskite crystals, especially all-inorganic CsPbBr 3 due to its complex phase diagram with two additional competing compositions. Here, we present a selective-cleaning strategy for CsPbBr 3 crystals grown in dimethyl sulfoxide (DMSO). We use a saturated solution of CsPbBr 3 in DMSO-H 2 O as a surface cleaner, combined with precleaning using DMSO-glycerol mixed solvents, to remove unreacted precursors and secondary phases without etching the CsPbBr 3 itself. X-ray detectors in Ag/CsPbBr 3 /Au architecture show exceptional linearity ( R 2 = 0.9995) to a wide X-ray dose range (0.077 to 33.6 μGyairs –1 ), achieving a sensitivity of 2,275 μCGyair –1 cm –2 under a 10 V bias and a detection limit of 11 nGyairs –1 . This strategy also increases charge carrier radiative recombination lifetime by 5× and X-ray sensitivity by 10× compared to hot DMSO cleaning. The present selective-cleaning strategy can expand to address surface contamination in a wide range of perovskites grown in solution.