Bright and efficient chiral coinage metal clusters show promise for use in emerging circularly polarized light-emitting materials and diodes. To date, highly efficient circularly polarized organic light-emitting diodes (CP-OLEDs) with enantiopure metal clusters have not been reported. Herein, through rational design of a multidentate chiral N-heterocyclic carbene (NHC) ligand and a modular building strategy, we synthesize a series of enantiopure Au(I)-Cu(I) clusters with exceptional stability. Modulation of the ligands stabilize the chiral excited states of clusters to allow thermally activated delayed fluorescence, resulting in the highest orange-red photoluminescence quantum yields over 93.0% in the solid state, which is accompanied by circularly polarized luminescence. Based on the solution process, a prototypical orange-red CP-OLED with a considerably high external quantum efficiency of 20.8% is prepared. These results demonstrate the extensive designability of chiral NHC ligands to stabilize polymetallic clusters for high performance in chiroptical applications.
Chiral coinage metal clusters show promise for use in emerging circularly polarized light-emitting materials and diodes but research on efficient circularly polarized organic light-emitting diodes (CP-OLEDs) with enantiopure metal clusters remains elusive. Herein, the authors design a multidentate chiral N-heterocyclic carbene (NHC) ligand which is used in the synthesis of enantiopure Au(I)-Cu(I) clusters with exceptional stability and demonstrate application of these clusters in the fabrication of CP-OLEDs