Synthesis of a rare-earth doped LNT (Li–Nb–Ti–O) phosphor by millimeter-wave heating

Phosphors based on the Li1+x−yNb1−x−3yTix+4yO3 (LNT, 0.05 ⩽ x ⩽ 0.25, y = 0) solid solution as host material that emit with bright red, green and blue (RGB) colors have been investigated. Rare-earth (RE)-doped LNT phosphors (RE3+: Eu, Sm, Er, Tm) are traditionally prepared by sintering at 1373 K in a conventional electric furnace (EF) for 24 h. However, a fast synthetic technique that uses less energy is required to improve the applicability of these materials. In the present study, LNT:RE3+ phosphors were successfully synthesized by millimeter-wave (MM) heating at 1173 K for only 1 h. Bright RGB color emissions were obtained, with LNT:Eu3+ and LNT:Sm3+ exhibiting red emission, LNT:Tm3+ blue emission and LNT:Er3+ green emission. The highest photoluminescence (PL) intensity, which was achieved for the composition Li1.11Nb0.89Ti0.11O3 doped with 2.5 wt.% of (RE)2O3, was almost equivalent to that of the specimen obtained upon EF heating.

► Phosphors have been successfully synthesized by millimeter-wave (MM) heating.
► The firing time was reduced from 24 h to 1 h.
► The resulting materials showed bright RGB (red, green and blue) colors emission.
► MM irradiation is a highly efficient, energy-saving method for formation of phosphors.