Broadband photoluminescence and nonlinear chiroptical properties in chiral 2D halide perovskites

Abstract Two-dimensional (2D) chiral halide perovskites (CHPs) have attracted broad interest due to their distinct spin-dependent properties and promising applications in chiroptics and spintronics. Here, we report a new type of 2D CHP single crystals, namely R/S-3BrMBA 2 PbBr 4 . The chirality of the as-prepared samples is confirmed by exploiting circular dichroism spectroscopy, indicating a successful chirality transfer from chiral organic cations to their inorganic perovskite sublattices. Furthermore, we observed bright photoluminescence spanning from 380 to 750 nm in R/S-3BrMBA 2 PbBr 4 crystals at room temperature. Such broad photoluminescence originates from free excitons and self-trapped excitons. In addition, efficient second-harmonic generation (SHG) performance was observed in chiral perovskite single crystals with high circular polarization ratios and non-linear optical circular dichroism. This demonstrates that R/S-3BrMBA 2 PbBr 4 crystals can be used to detect and generate left- and right-handed circularly polarized light. Our study provides a new platform to develop high-performance chiroptical and spintronic devices.