Circularly polarized perovskite luminescence with dissymmetry factor up to 1.9 by soft helix bilayer device

Metal halide perovskites are exceptional light-emitting materials. Endowing perovskites with circularly polarized luminescence (CPL) offers great promise for innovative applications, but the existing strategies are inefficient in acquiring large dissymmetry factor (glum), high quantum efficiency, and long-term stability. Here, we demonstrate bright and stable CPL with a glum value up to 1.9 from perovskites in chiral liquid crystal (LC)-based soft helix devices featuring a bilayer architecture. The incorporation of an optimized polymer of polyacrylonitrile (PAN) in the bilayer device remarkably improves luminescent efficiency and stability of perovskite, while perfectly preserving optical and stimuli-responsive characteristics of chiral LCs. The resulting bilayer devices allow systematical composition engineering of both perovskite and soft helix and enable full-color CPL with high glum values. Moreover, CPL-active devices with diverse graphical patterns and reversible thermal-switching behavior can further expand the scaffold for cryptology and anti-counterfeiting applications.