Chiral Copper(I) Iodide Cluster Hybrids Realize Efficient Circularly Polarized OLEDs

Chiral halide emitters demonstrate great potential in circularly polarized organic light-emitting diodes for future 3D displays. However, achieving circularly polarized luminescence with cost-effective and environmentally friendly halide materials remains a significant challenge. In this study, we introduced classic chiral organic ligands into a [Cu4I4] inorganic core to develop efficient circularly polarized luminescence (CPL)-active halide materials. Through the synergistic design of (S/R)-3-methylmorpholine with the [Cu4I4] core, we successfully synthesized a pair of copper(I) enantiomers Cu4I4(S/R-3-methylmorpholine)4 (S/R-Cu4I4). These enantiomers not only exhibit distinct mirror-image CPL signals but also possess excellent thermal stability and high luminescence efficiency. OLED devices fabricated based on the S/R-Cu4I4 enantiomers achieved high-performance circularly polarized electroluminescence (CPEL), with a brightness of 6506 cd m–2, an external quantum efficiency (EQE) of 4.2%, a CPEL dissymmetry factor (gEL) of +8 × 10–3, and an extremely low efficiency roll-off of only ∼6% at 1000 cd m–2 brightness. This study demonstrates the feasibility of employing simple chiral ligands and low-cost metals to develop highly efficient CPL-active halide materials. The findings provide a practical strategy for constructing high-performance chiral copper-based halide emitters while also establishing the first pioneering implementation of Cu4I4 cluster materials in CPEL applications.