Layer-by-layer alloying of NIR-II emissive M50 (Au/Ag/Cu) superatomic nanocluster

The intermetallic synergy plays a critical role in exploring the chemical-physical properties of metal nanoclusters. However, the controlled doping or layer-by-layer alloying of atom-precise metal nanoclusters (NCs) has long been a challenging pursuit. In this work, two novel alloy nanoclusters [PPh 4 ] 4 [Ag 32 Cu 18 (PFBT) 36 ] ((AgCu) 50 ) and [PPh 4 ] 4 [Au 12 Ag 20 Cu 18 (PFBT) 36 ] (Au 12 (AgCu) 38 ), where PFBT is pentafluorobenzenethiolate, with shell-by-shell configuration of M 12 @Ag 20 @Cu 18 (PFBT) 36 (M = Ag/Au) were synthesized by a facile one-pot co-reduction method. Notably, a fingerprint library of [Ag 50− x Cu x (PFBT) 36 ] 4− ( x = 0 to 50) from Ag 50 to Cu 50 has been successfully established as revealed by electrospray ionization mass spectrometry. Single-crystal X-ray diffraction analysis of trimetallic Au 12 (AgCu) 38 confirmed the layer-by-layer alloying under reducing conditions. What is more, (AgCu) 50 and Au 12 (AgCu) 38 both show broad photoluminescence (PL) peak in the second near-infrared (NIR-II) window, and the Au doping in the innermost shell considerably enhances the photoluminescence intensity. This work not only offers an insight in the process of metal cluster alloying but also provides a platform to study the doping-directed PL properties in the multimetallic cluster system.