Effect of ZnS nanoparticles on the Judd-Ofelt and radiative parameters of Sm3+ ions in sol-gel silica matrix

Sm3+ singly doped and Sm3+ co-doped with varying concentration of ZnS nanoparticles (ZnS NPs) in silica matrix were fabricated via sol-gel route and investigated by various structural, thermo-gravimetric and spectroscopic techniques. Structural characterizations were done by XRD, EDX, TEM and FTIR whereas thermogravimetric characterization was performed by TGA/DTG technique. The structural studies reveal the presence of nanosized ZnS particles in the amorphous silica matrix. Spectroscopic studies were performed through absorption, excitation, emission and decay spectra of the fabricated samples. The dependence of Judd-Ofelt and various radiative parameters of Sm3+ on the concentration of ZnS NPs in the studied matrix were evaluated. Significantly high value of Omega(2) obtained for the present system reveals effective network modifying nature of the ZnS NPs. The PL behaviour showed strong concentration dependence on ZnS NPs and showed optimum for the ZnS concentration of 0.5 M. The emission transition (4)G(5/2) -> H-6(9/2) of Sm3+ corresponding to the red colour observed at 642 nm for silica matrix in the present study showed excellent radiative behaviour compared to other popular glass hosts. This indicates ZnS NPs co-doped Sm3+ sol-gel silica matrix to be a prospective candidate for laser and other optical device applications.