Visible Quantum Cutting and Energy Transfer in Tb~(3+)-Doped KSr(Gd,Y)(PO_4)_2 Under VUV-UV Excitation

摘要

KSr(Gd,Y)(PO_4)_2: Tb~(3+) phosphors were synthesized using the high-temperature solid-state reaction method. The VUV-UV spectroscopic properties of these phosphors were studied. The results show that efficient energy transfer (ET) from Gd~(3+) to Tb~(3+) occurs in this system, and the ET efficiency increases with increasing of Tb~(3+) doping concentrations, which is evidenced that both the emission intensity and decay time of Gd~(3+) decreases with increasing Tb~(3+) doping concentrations. Visible quantum cutting via cross relaxation between the neighboring Tb~(3+) ions was observed in the high Tb~(3+) concentration doped sample. In addition, the emission color of KSr(Gd,Y) (PO_4)_2: Tb~(3+) phosphors can be tuned from blue to yellowish-green by varying the doping concentration of Tb~(3+). Under 147 nm excitation, the sample KSrGd_(0.5)(PO_4)_2: 0.5Tb~(3+) exhibits the strongest emission, which is about 70% of the commercial green-emitting phosphor Zn_2SiO_4: Mn~(2+) indicating the potential application of this phosphor for plasma display panels, Hg-free lamps, and three-dimensional displays.