Giant Intrinsic Chirality Amplification of Aqueous Lead Halide Perovskite Nanocrystals via H‐Bond Driven Self‐Assembly Superstructures

ABSTRACT Self‐assembly of lead halide perovskite nanocrystals into long‐range ordered superstructures can achieve reorganization of the morphological and chiroptical properties. Here, an efficient method is reported to achieve highly intrinsic chiral amplification in aqueous perovskite nanocrystals (PNCs) through freezing‐induced strong H‐bond driving self‐assembly into asymmetric superstructures. The aqueous PNCs with a high photoluminescence quantum yield (PLQY) of 92% are successfully synthesized by the water‐assisted strategy. Low temperature enhanced hydrogen bond network regulates the freezing‐induced self‐assembly of PNCs into asymmetric superstructures in aqueous solution, notably enhancing intrinsic circularly polarized luminescence (CPL) emission with over 200‐fold amplification of dissymmetry factor ( g lum ), along with the g lum of 4.1 × 10 −3 at 253 K. The emission wavelength of CPL could be tunable by anion exchange in aqueous solution. Our finding offers a pioneering insight into efficiently amplifying intrinsic chiroptical response in low‐symmetry perovskites, opening a new avenue for the design of novel self‐assembly perovskite materials with superior optical properties and CPL character.