Simultaneously achieving room-temperature circularly polarized luminescence and high stability in chiral perovskite nanocrystals via block copolymer micellar nanoreactors

Abstract

Chiral hybrid halide perovskites have emerged as promising candidates for next-generation optoelectronic and spintronic devices owing to their outstanding chiroptical and electrical properties. However, designing chiral perovskite nanocrystals (NCs) that exhibit high stability as well as notable chiroptical activity under ambient conditions is still challenging. In this study, a novel strategy is developed to fabricate chiral perovskite NCs based on block copolymer inverse micelles with supramolecular chirality obtained by the self-assembly of optically inactive building blocks, polystyrene-block-poly(2-vinyl pyridine) (PS-b-P2VP) and dl-alanine (dl-ala). The selective occupation of perovskite precursors within chiral micellar cores ensures an efficient chirality transfer to the electronic states of the perovskite NCs, resulting in a high chiroptical response with an anisotropy factor of -2.0 x 10(-4), similar to those of the chiral ligand-modified perovskite NCs. Furthermore, circularly polarized luminescence performance is observed at room temperature. Simultaneously, the robust surface encapsulation by PS-b-P2VP/dl-ala inverse micelles protects the perovskite NCs from moisture, heat, and air more effectively than the pure PS-b-P2VP inverse micelles. This approach can be used to realize large-scale and low-cost production of chiral perovskites and can be extended to engineer chiral perovskite materials by judiciously controlling the block copolymer self-assembly.