Au10Ag17(TPP)10(SR)6Cl5 nanocluster: structure, transformation and the origin of its photoluminescence

Abstract

Nanocluster photoluminescence (PL) has important practical applications and its rationalization is therefore of significant interest. Here, we report the synthesis, structure determination and photoluminescence of Au₁₀Ag₁₇(TPP)₁₀(SR)₆Cl₅ (TPP = triphenylphosphine, SR = 3, 5-bis(trifluoromethyl)thiophenol, denoted as Au₁₀Ag₁₇). Au₁₀Ag₁₇ exhibited a low photoluminescence quantum yield (PLQY) of 2.8%, which could be increased 15-fold by removing the two terminal silver atoms to give Ag_xAu_25−x(SR)₅(TPP)₁₀Cl₂²⁺ (x = 11–13, SR = 2-phenylethylmercaptan, abbrev. Au₁₂Ag₁₃). The discovery of such a PL switch constitutes an interesting opportunity to further understand the origin of fluorescence in nanoclusters.