Tunable color emission in K3Gd(PO4)2:Tb3+,Sm3+ phosphor for n-UV white light emitting diodes

A series of K3Gd(PO4)2:Tb3+,Sm3+ phosphors were synthesized through solid state reaction. By co-doping Tb3+ and Sm3+ into K3Gd(PO4)2 host and singly varying the doping concentration of Sm3+, tunable colors from green to yellow and then to orange were obtained in K3Gd(PO4)2:Tb3+,Sm3+ phosphors under the excitation at 373 nm. The energy transfer process from Tb3+ to Sm3+ was verified through luminescence spectra and fluorescence decay curves. Moreover, the energy transfer mechanism was demonstrated to be the quadrupole-quadrupole interaction. The results indicated that K3Gd(PO4)2:Tb3+,Sm3+ phosphors could be a potential application for n-UV white light emitting diodes.

PL spectra of K3Gd0.5–x(PO4)2:0.5Tb3+, xSm3+ (x=0, 0.005, 0.01, 0.03, 0.05, 0.07, 0.09) under 373 nm (a); CIE chromaticity diagram of K3Gd0.5–x(PO4)2:0.5Tb3+, xSm3+ phosphors under the excitation at 373 nm (b) (the inset shows the digital photos of the selected K3Gd0.5–x(PO4)2:0.5Tb3+, xSm3+ phosphors under the irradiation of 365 nm UV lamp)Figure optionsDownload full-size imageDownload as PowerPoint slide