Synthesis and luminescence investigation of RE3+ (Eu3+, Tb3+ and Ce3+)-doped lithium silicate (Li2SiO3)

Synthesis and photoluminescence (PL) investigations of lithium metasilicate doped with Eu3+, Tb3+ and Ce3+ were carried out. PL spectra of Eu-doped sample showed peaks corresponding to the 5D0→7Fj (j=1, 2, 3 and 4) transitions under ultraviolet excitation. Strong red emission coming from the hypersensitive 5D0→7F2 transition of Eu3+ ion suggested the presence of the dopant ion in structurally disordered environment. Tb3+-doped silicate sample showed blue-green emission corresponding to the 5D4→7Fj (j=6, 5 and 4) transitions. Ce-doped sample under excitation from UV, showed a broad emission band in the region 350-370 nm with shoulders around 410 nm. The fluorescence lifetimes of Eu3+ and Tb3+ ions were found out to be 790 and 600 μs, respectively. For Ce3+, the lifetime was of the order of 45 ns. PL spectra of the europium- and terbium-doped samples were compared with commercial red (Y2O3:Eu3+) and green (LaPO4:Tb3+) phosphors, respectively. It was found that the emission from the doped silicate sample was 37% of the commercial phosphor in case of the Tb-doped sample and 8% of the commercial phosphor in case of the Eu-doped sample.