Transformation of Trap States during the Formation of Luminescent Core/Shell Nanostructures Based on Ag 2 S Quantum Dots

Results are presented from studying regularities of photoprocesses that determine the luminescence of colloidal Ag 2 S quantum dots during the formation of SiO 2 shells. It is found that shell formation is accompanied by a significant increase in the quantum yield of recombination luminescence (up to 5 times), a less noticeable increase in the decay time of luminescence, and a sharp decrease in the concentration of one type of shallow trap states with an ionization energy of around 0.14 eV. It is concluded that localized states with a depth of 0.14 eV are centers of the nonradiative recombination of charge carriers.