Combustion synthesis and photoluminescence properties of a novel blue-green-emitting Er3+ and Li+ co-doped LaNbTiO6

A single-phase blue-green light emitting phosphor, LaNbTiO6: Er3+, Li+, was synthesized by using a simple and facile sol–gel combustion approach. Its structure and photoluminescence (PL) properties were investigated as a function of Er3+ and Li+ ion concentration. The luminous mechanisms of the Er3+ doping and Er3+/Li+ co-doping in the LaNbTiO6 host were also discussed, including the intra-4f-transitions of Er3+ and the charge compensation of Li+. The incorporation of Li+ ions into LaNbTiO6 lattice further altered the local structure and symmetry of the crystals field around Er3+. Concentration quenching occurred when Er3+ and Li+ reached certain levels. Furthermore, the critical transfer distance of Er3+ → Er3+ in the phosphor was calculated. The absolute quantum efficiencies and the fluorescence decay time of the phosphors were studied. The phosphor produced blue-green light, presenting CIE chromaticity coordinates of (0.211, 0.277) and (0.214, 0.320).