4‐Bromo‐Butyric Acid‐Assisted In Situ Passivation Strategy for Superstable All‐Inorganic Halide Perovskite CsPbX3 Quantum Dots in Polar Media

(CPB) QDs obtained in water show high photoluminescence quantum yields (PLQYs) of 86.4 % and their PL features of CPB QDs have no significant change after being dispersed in aqueous solution for 96 h, which implies the structure of CPB QDs is unchanged. The results provide a viable design strategy to synthesize all-inorganic perovskite CPX QDs with strong stability against the attack of polar solvents and shed more light on their surface chemistry.