Optical properties of CdTe quantum dots in silicate glasses containing CaO

Embedding CdTe QDs into glass can improve the thermal and chemical stability of QDs, which facilitates their wide and endurable applications. However, the small tunable spectral range of photoluminescence, low quantum efficiency, and large full width at half maximum limit their wide applications. In this work, effect of introduction of CaO into glass matrix on the formation and optical properties of CdTe QDs is investigated. High concentration of CaO in glasses increases the solubility of Te in glasses, and consequently hinders the precipitation of CdTe QDs in glasses. By adjusting the heat-treatment temperature, average diameters of CdTe QDs are tuned in the range of 2.5–9.0 nm and their photoluminescence bands are tuned from 550 to 800 nm. More importantly, the absolute photoluminescence quantum yield is boosted up to 41.9 %. Results reported in this work indicate that CdTe quantum dots embedded in glasses are promising for applications in light-emitting devices.