Construction of an Au12Cd2 nanocluster with circularly polarized luminescence by a metal- and ligand-exchange strategy

Abstract

Excellent luminescence properties and unique chiral structures enable nanoclusters to be a novel class of circularly polarized luminescence (CPL) materials, and their precise structures facilitate the clarification of structure–activity relationships. However, efficiently preparing nanoclusters with CPL properties is still a great challenge. In this work, the luminescent properties as well as the molecular symmetry were simultaneously manipulated to transform the centrosymmetric Au₁₄Cd₁ into a chiral Au₁₂Cd₂ nanocluster, which has CPL properties. In detail, Cd doping and chiral-ligand exchange were performed simultaneously on the Au₁₄Cd₁ nanocluster to realize its photoluminescence enhancement and chiral-framework construction by increasing the alloying degree which is defined as deep-alloying and chiral ligand induction at the same time, resulting in the formation of an Au₁₂Cd₂ nanocluster with CPL properties. Further investigations revealed an increased alloying degree in the structure-maintained M₆ kernel of Au₁₂Cd₂, which results in a 15-fold enhancement in quantum yield.