Formamidine Engineering the Lattice Distortion of Chiral Halide Perovskites for Efficient Blue Circularly Polarized Emission

摘要

Chiral halide perovskites have emerged as promising circularly polarized lightsources due to their great potential applications in 3D displays, optical datastorage, and optical communication devices. However, to date, chiral halideperovskites with efficient blue circularly polarized luminescence (CPL) arescarcely unearthed. Herein, through formamidine engineering to decreaselattice distortion, the first new types of chiral corrugated 2D halide perovskitesare presented (R/S)-(BPEA)FAPbBr_4·H_2O (2-R/S)(BPEA = 4-bromophenylethylaminium, FA = formamidinium). Interestingly,driven by the incorporation of FA organic cations, the chiral perovskite layerrealizes the transformation from (100)-oriented (R/S)-(BPEA)_2PbBr_4·H_2O(1-R/S) to (110)-oriented 2-R/S accompanying with reduced lattice distortion.More importantly, (110)-oriented chiral perovskites 2-R exhibit remarkableblue CPL with large asymmetry factors (glum =8.4 × 10~(?3)). This work offers anexciting approach to realizing efficient blue CPL and promotes their furtherapplications in photoelectronic devices.