Luminescence of Ag$_2$S/SiO$_2$ colloidal quantum dots decorated with small Au nanoparticles

A tenfold increase in the quantum yield of defect luminescence in the region of 750 nm with a simultaneous increase in its decay time from 4 to 200 ns, due to decoration of surface of quantum dots (QDs) Ag$_2$S/SiO$_2$ (5.0 $\pm$ 1.5 nm) with Au nanoparticles (NPs) (2.0 $\pm$ 0.5 nm). Based on analysis of the luminescence kinetics at temperatures of 77 and 300 K, it was concluded that such a nonspecific manifestation of the plasmon–exciton interaction is caused by the influence of polarization effects from Au NPs on the properties of shallow traps involved in the formation of the defect luminescence kinetics of Ag$_2$S/SiO$_2$ QDs.