A Cooperative Structural Dimension and Clusters Chirality in Antimony Halide Hybrids for Efficient Circularly Polarized Electroluminescence

Chiral metal-halide materials often suffer from inherent trade-off between photoluminescence efficiency and chiroptical asymmetry (g value); low-dimensional structures typically deliver high emission efficiency but small g values, whereas higher-dimensional counterparts afford larger g values at the cost of reduced luminescence efficiency. To overcome this limitation, we introduce a cluster-level chirality strategy in a 0D framework by incorporating chiral metal halide clusters. Herein, we rationally design and synthesize a pair of enantiomeric antimony(III) halide hybrids, [(R,R)/(S,S)(PPh₂)₂C₄]₂[Sb₄Cl₁₆] (R/S-DPPB-Sb) in which bulky chiral phosphonium cations template previously unreported isolated [Sb₄Cl₁₆]^4- clusters assembled into a helical lattice. These enantiomers exhibit bright self-trapped excitons emission at 625 nm with photoluminescence quantum yields above 40%, along with strong circularly polarized luminescence (g_lum ≈ ±7 × 10^-3), among the highest reported to date for chiral Antimony-based hybrids. Remarkably, we further demonstrate circularly polarized LEDs using R/S-DPPB-Sb as the emitter, achieving an external quantum efficiency of 1.48% and a notable CP-EL dissymmetry factor (|g_EL| > 9 × 10^-3). The strong chiroptical response originates from the pronounced distortion of the [Sb₄Cl₁₆]^4- clusters and their helical supramolecular packing. This work establishes antimony halide clusters as a promising chiral emitter and provides a viable route toward high-performance, lead-free CPLEDs.