Hydrogen-Bond Reinforced Chiral Indium-Based Hybrid Metal Halides for Circularly Polarized Luminescence

Circularly polarized luminescence (CPL) materials are highly attractive for next-generation photonic and information technologies, yet achieving both a large luminescence dissymmetry factor (g_lum) and near-unity photoluminescence quantum yield (PLQY) remains challenging in lead-free chiral metal halides. Here, we report a pair of zero-dimensional chiral indium-based chloride enantiomers, (R/S-AQ)₂In_1-xSb_xCl₇ (AQ = 3-aminoquinuclidine), enabled by Sb³⁺-doping. A dense interfacial N-H···Cl hydrogen-bond network strengthens organic-inorganic coupling and is likely to facilitate chiral transfer, while Sb³⁺ incorporation activates highly efficient broadband self-trapped exciton emission. As a result, the enantiomers exhibit near-unity PLQY (up to 99.32%) together with mirror-image CPL signals with |g_lum| ≈ 2.0 × 10^-2. A CP-LED based on a commercial 280 nm UV chip shows stable device emission under electrical driving while retaining circular polarization. Our work demonstrates an effective strategy for co-optimizing efficiency and polarization in chiral metal halides toward practical CPL devices.