Fluorescence or Phosphorescence? The Metallic Composition of the Nanocluster Kernel Does Matter

It remains challenging to manipulate the nature of photoluminescence as either fluorescence or phosphorescence for a correlated cluster series. In this work, two correlated nanoclusters, Au5Ag11(SR)8(DPPOE)2 and Pt1Ag16(SR)8(DPPOE)2 with comparable structure features, were synthesized and structurally determined. These two alloy nanoclusters displayed distinct photoluminescent nature—the Au5Ag11 nanocluster is fluorescent, whereas the Pt1Ag16 nanocluster is phosphorescent. The decay processes of the excited electrons in these two nanoclusters have been explicitly mapped out by both experimental and theoretical approaches, disclosing the mechanisms of their fluorescence and phosphorescence. Specifically, the metallic compositions of the nanocluster kernels mattered in determining their photoluminescent nature. The results herein provide an intriguing nanomodel that enables us to grasp the origin of photoluminescence at the atomic level, which further paves the way for fabricating novel nanoclusters or cluster‐based nanomaterials with customized photophysical properties. The metallic compositions of nanoclusters can dictate whether their photoluminescence is fluorescence or phosphorescence. This effect is demonstrated with Au5Ag11 and Pt1Ag16 nanoclusters that have comparable structures but different compositions.