Effect of ligands PPIA and TOPO on radiative behaviour of Eu3+ ions in sol-gel silica matrix

Eu3+ singly doped and Eu3+ co-doped with ligands PPIA and TOPO in silica matrix were fabricated via sol-gel route and investigated by structural and spectroscopic techniques. Structural studies reveal the amorphous na-ture of the silica matrix as well as the presence of the ligands in the matrix. Spectroscopic studies were performed through absorption, excitation, emission and time-correlated decay spectra of the fabricated samples. The phenomenological Judd-Ofelt parameters were calculated from the observed photoluminescence spectra considering the integrated intensity ratio of the allowed electric and magnetic dipole transitions. The dependence of Judd-Ofelt intensity parameters and radiative parameters of Eu3+ ions on the ligands PPIA and TOPO in the studied matrix were evaluated. The radiative efficiency improved significantly with the addition of the ligands and showed the maximum for both PPIA and TOPO co-doped sample. The emission transition (D0 -> F2)-D-5-F-7 observed at 616 nm wavelength of Eu3+ corresponding to the red colour in the present study showed excellent radiative behaviour compared to other popular glass hosts. The study suggests PPIA and TOPO co-doped Eu3+ sol-gel silica matrix as a prospective candidate for optical device applications harnessing the red emissions.