The effect of CdSe nanoparticles on the optical properties of Pr³⁺ ions in bismuth boro-tellurite glasses

Glasses are ideal host for rare-earth (RE) ions. The optical properties of RE ions can be varied by modifying their chemical environments through compositional changes or by having metal/semiconducting nanoparticles grown inside these gasses. We studied the influence of CdSe nanoparticles on the optical properties of Pr³⁺ doped bismuth boro-tellurite glasses. In order to grow these nanoparticles, CdSe powder is added with the starting materials while preparing the glasses using the melt-quench technique. These glasses are then subjected to a process of controlled annealing near the glass transition temperature. During this annealing process, CdSe molecules that are uniformly dispersed in the glass matrix undergo thermal diffusion and coagulate to form nanoparticles. The average size of these nanoparticles can be changed by varying the duration of the annealing. Our studies show that the Pr-O bond becomes less covalent when CdSe nanoparticles are present in the glass. Glasses with CdSe nanoparticles show significant enhancement for the stimulated emission cross section of Pr³⁺ fluorescence. The presence of larger CdSe nanoparticles can considerably enhance the nature and the intensity distribution of the light emitted by these glasses.