Assembling Octahedral Pt₂Ag₄ Clusters for High-Efficiency Circularly Polarized Luminescence

Establishing atom-precise and controllable self-assembly of metal clusters to achieve high-efficiency circularly polarized luminescence (CPL) is especially fascinating, yet it creates considerable challenges. Here, two enantiomeric pairs of dimer clusters R/S-Pt₄Ag₈-green and R/S-Pt₄Ag₈-orange composed of two octahedral Pt₂Ag₄ monomers through Pt-Pt bonds are constructed, which show a 28-fold increase in photoluminescence quantum yield (PLQY) compared with the reported monomer in solution. The solid-state chiral dimer R/S-Pt₄Ag₈-orange shows a PLQY of 87% without an aggregation-caused quenching effect. The intercluster distances and arrangements of the chiral cluster can be modulated through the ligand configuration and solvent stimuli, giving rise to the reversible transformations between chiral single crystals, concomitant with high-contrast optical/chiroptical switching. Additionally, by further assembling chiral Pt-Ag clusters with Ag⁺, a chiral 3D cubic lattice with high-efficiency red-emitting CPL is achieved. Furthermore, high-efficiency luminescence, intrinsic chirality, and the adjustable assembly behaviors of these chiral cluster assemblies bestow them with excellent smart CPL switching properties. This work opens a new avenue for high-efficiency CPL-active metal clusters by regulating metal-metal interactions.