Optical properties and up-conversion of Pr3+ doped CdS nanoparticles in sol–gel glasses

Silica glasses containing Pr3+ with and without CdS nanoparticles were prepared by sol–gel technique. The influence of CdS nanoparticles on Pr3+ doped glass was studied by absorption, photoluminescence and up-conversion. From the measured intensities of various absorption bands of these glasses, the Judd–Ofelt parameters Ω2, Ω4 and Ω6 have been evaluated. The radiative transition probability (A), radiative lifetime (τR), branching ratio (βR) and integrated emission cross-section (σP) were calculated from excited states of 3P1 and 3P0 levels. The up-conversion emissions were found in the green, orange and red regions under 800 nm excitation with peaks 559, 612 and 688 nm respectively. On excitation with 370 nm also leads to similar green, orange and red regions.