Photoluminescence properties of ZnS/CdS/ZnS quantum dot–quantum wells doped with Ag+ ions

Enhanced photoluminescence and postirradiation luminescence is reported from Ag+-doping ZnS/CdS/ZnS quantum dot–quantum wells (QDQWs) prepared via a reverse micelle process. Controlling the final mole ratio of water-to-surfactant in H2O/Heptane system, the size of a QDQW was estimated to be ~6 nm. Compared to undoped QDQWs, the doped QDQWs exhibited a much stronger orange emission, with a peak blue shift from 615 to 590 nm; the quantum yield was increased from 2.63 to 9.31%, and the remaining luminescence intensity after 2 h ultraviolet irradiation was increased from 71.2 to 94.7%. This improved quantum yield and postirradiation luminescence intensity for doped QDQWs was ascribed to the introduction of Ag+ ions to CdS wells.