Effect of Alkali Metal Ions(Li~+, Na~+ and K~+) on the Luminescent Properties of ZnTiO3:Eu3+ Phosphors

A series of red emitting ZnTiOphosphors co-doped with Euand alkali metal ions(Li~+, Na~+ and K~+) was prepared by sol-gel method. The crystal structure of the phosphors was investigated by using X-ray diffraction(XRD) and transmission electron microscopy(TEM) after annealing at 700 ℃. The results show that the crystal structure belongs to the hexagonal phase of ZnTiOwith space group R-3:R. The influence of site occupancy of different alkali metal ions on the emission of ZnTiO:Euphosphors was investigated in detail. The emission intensity was significantly enhanced by introducing alkali metal ions. In contrast to Eusingly doped ZnTiO, the red emission intensities of ZnTiO:Euwith 4 mol% alkali metal ions(Li~+, Na~+, K~+) were enhanced by about 2.1, 1.7 and 1.4 times, respectively. In addition, the Commission Internationale Ed I’eclairage(CIE) chromaticity coordinates of ZnTiO:Eu, Li~+(0.672, 0.328) are quite similar to the National Television Standard Committee(NTSC) standard values for the red(0.670, 0.380).