Spectroscopic properties of Sm3+ and CdS co-doped in sol-gel silica glass

Sm3+- doped silica glass co-doped with CdS nanoparticles have been prepared by sol-gel method. FTIR spectra of the samples at different annealing temperatures show the gradual removal of hydroxyl group. XRD pattern shows crystalline nature of the silica host along with CdS peak. The optical absorption and fluorescence properties have been investigated using Judd-Ofelt theory. The Judd-Ofelt intensity parameters have been obtained from the absorption spectrum following the trend Ω2 > Ω4 > Ω6 and the large value of Ω2 indicates covalency of the rare earth bonding. Under excitation with 370 nm, photoluminescence peaks have been observed in the green, yellow, orange and red region as a result of radiative relaxation from the 4G5/2 state