Wavelength-tunable absorption and luminescence of SiO2-Al2O3-ZnO-Na2O-K2O-NaF glasses with PbS quantum dots

- SiO2-Al2O3-ZnO-Na2O-K2O-NaF glass doped with PbO and elemental sulfur.
- Controllable growth of PbS quantum dots with average diameter of 3.0-6.5 nm.
- Detailed investigation of optical absorption and photoluminescence.
- Influence of heat-treatment temperature (480-520 °C) and duration (5-130 h).
- Variation of peak excitonic absorption coefficient within 7-45 cm−1 range.

Lead sulfide quantum dots (QDs) with average diameter of 3.0-6.5 nm were grown in novel SiO2-Al2O3-ZnO-Na2O-K2O-NaF glasses highly-doped with PbO and elemental sulfur by means of single-stage heat-treatment at temperatures slightly lower the vitrification point. Introduction of two alkaline components to the glass system allows us to perform the synthesis without control of sulfur evaporation, while stabilization of PbS crystal nuclei was provided by addition of NaF. Optical absorption and photoluminescence of these PbS-QD-doped glasses were studied in dependence on treatment temperature (480-520 °C) and duration (5-130 h). The growth rate of QDs was substantially enhanced with the increase of treatment temperature. The position of 1S-1S excitonic absorption peak was tuned from 0.75 to 1.6 μm, accompanied by management of peak absorption within 7-45 cm−1 range. Intense Gaussian-shaped photoluminescence associated with radiative exciton recombination from 1S-1S state was observed in 1.1-1.6 μm spectral range.