Abnormal Chiral Coupling for Efficient and Stable Reduced-Dimensional Perovskite Emitters.

Highly efficient and stable reduced-dimensional halide perovskite (RDP) emitters are of vital importance for perovskite optoexcitonic devices. However, simultaneous improvement of their luminescence efficiency, stability, and phase purity based on principles without using external passivators has been a tremendous challenge. Here, an abnormal chiral coupling effect is introduced in the chiral benzene halide RDPs. Our strategy facilitates the construction of the network of both short-range nanoscale lattices and long-range superstructures, which leads to improved phase purity, reduced defects, weakened exciton-phonon scattering, and efficient excited-state transfer pathways. Consequently, an increment of photoluminescence quantum yield by over 35% compared to that of achiral counterpart was realized. This strong chiral coupling effect also enables the realization of stable and low threshold continuous wave lasing over 0.5 h at room temperature. Our study introduces an improved design principle for RDPs to control the defects, phase purity, crystal nano/microstructure, molecular interaction, and excited-state process for highly efficient and stable perovskite optoexcitonic devices.