title: [Study on Synthesis and Luminescence Mechanism of Novel Green Sr3Y(PO4)3:Ce3+, Tb3+ Phosphors].
abstract: A novel green light-emitting phosphor Sr3Y(PO4)3Ce(3+), Tb(3+) was synthesized by the traditional high temperature solid state reaction method. Luminescence mechanism and crystal structure were investigated by X-Ray Diffraction (XRD) and photoluminescence spectra (PL). The XRD patterns demonstrate that the samples belong to the single phase of Sr3Y(PO4)3 in experimental doping concentrations range. Obviously, the excitation band of Sr3Y(PO4)3:Tb(3+) and the emission of Sr3Y(PO4)3:Ce(3+) have a significant spectral overlap in the wavelength range of 330~380 nm, which implies the great possibility of an efficient ET from Ce(3+) to Tb(3+). Under the 315 nm ultraviolet excitation, a blue emission(320~420 nm) from Ce(3+) and a yellowish-green emission (480~500, 530~560 nm) from Tb(3+) were obtained from Sr3Y(PO4)3:Ce(3+), Tb(3+). When the Ce(3+) concentration was 7%, the emission could be adjusted from blue to green region by tuning the Tb(3+) doping concentrations from 1% to 50% through an energy transfer process. This text plot the schematic energy levels of Ce(3+), and Tb(3+) with electronic transitions and energy transfer processes in Sr3Y(PO4)3:Ce(3+), Tb(3+), which disclose the electron motion processes of Sr3Y(PO4)3:Ce(3+), Tb(3+). From the dependence of relative emission intensity of Ce(3+), Tb(3+) ((5)D4 --> (7)Fj) and ET efficiency from Ce(3+) to Tb(3+) on the concentrations of Tb(3+), It can be seen that the relative intensity of Tb(3+) and the values of ηET increase gradually with the increasing of Tb(3+) as well as the relative intensity of Ce(3+) decreases remarkably. The largest energy transfer efficiency reaches as high as 80% when the concentration of Tb(3+) was 50%, demonstrating the efficient energy transfer from Ce(3+) to Tb(3+). The CIE chromaticity coordinate positions are plotted, as can be seen the emitting color of Ce(3+) and Tb(3+) singly doped Sr3Y(PO4)3:Ce(3+), Tb(3+) phosphor are blue and yellowish green, respectively. The emitting color of samples Sr3Y(PO4)3:Ce(3+), Tb(3+) changes from blue region to green region with the rising doping contents of Tb(3+). Sr3Y(PO4)3:Ce(3+) and Tb(3+) phosphor can be used as a green light-emitting phosphor in white LED devices and LCD backlights.
authors.forename: Guo-shuai
authors.initials: GS
authors.lastname: Dong
authors.forename: Hai-bo
authors.initials: HB
authors.lastname: Liu
authors.forename: Li
authors.initials: L
authors.lastname: Luo
authors.forename: Yin-hai
authors.initials: YH
authors.lastname: Wang