Precipitation of PbS quantum dots in glasses by thermal diffusion of Ag+ ions from silver pastes

Precipitation of PbS quantum dots (QDs) in glasses was controlled by thermal diffusion of Ag+ ions from Ag paste at a temperature of 320 °C. After subsequent heat treatment at 420–450 °C, PbS QDs formed in the near-surface regions where the silver paste was applied. After the glasses were heat-treated at 440 or 450 °C, PbS QDs were larger in Ag-affected surface regions than in Ag-free glasses. PbS QDs grew in Ag-affected regions when they were heat-treated at 420 or 430 °C. Ag+ ions penetrated ~ 25 μm from the glass surface after thermal diffusion of Ag+ ions and subsequent heat treatment at 430 °C. Thermal diffusion of Ag+ ions from Ag paste is a viable method to control the precipitation and spatial distribution of PbS QDs in glasses.