Tunable emitting phosphors K3Gd(PO4)2: Tm3+-Dy3+ for light-emitting diodes and field emission displays

Abstract

Spectroscopic properties of K3Gd(PO4)2: Tm3+-Dy3+ under ultraviolet (UV) light and low-voltage electron beam excitations were investigated. Upon direct excitation Tm3+ from its 6F6 level to 1D2 level, the decrease of emission intensity and lifetime of Tm3+ 1D2-3F4 emission with increasing concentration of Dy3+ in K3Gd(PO4)2: Dy3+, Tm3+ confirmed the occurrence of energy transfer from Tm3+ to Dy3+. Besides, K3Gd(PO4)2: Dy3+, Tm3+ could be efficiently excited by 358 nm UV light and its emission color could be tuned from blue to yellow by codoping Tm3+. When 1% Tm3+ and 8% Dy3+ were codoped in the K3Gd(PO4)2, intensive white emitting light with CIE of (0.338, 0.347) was achieved upon 358 nm excitation. The cathodoluminescence spectra of K3Gd(PO4): Tm3+, Dy3+ phosphors as a function of accelerating voltage and filament current were also measured. Under low-voltage electron-beam excitation, K3Gd(PO4)2: Tm3+, Dy3+ phosphors exhibit excellent tunable emitting property. All of the above results reveal that the as-prepared K3Gd(PO4)2: Tm3+, Dy3+ phosphors have potential applications in white LEDs and FEDs.