New red- and green-emitting phosphors, AYP(2)O(7.5): RE3+ (A=Ca and sr; RE=Eu and tb) under near-UV irradiation

Abstract

New red- and green-emitting phosphors, AY(1-x)P(2)O(7.5):xRE(3+) (A=Ca and Sr; x=0.01, 0.03, 0.05, 0.10; RE=Eu and Tb) were synthesized by the conventional ceramic route and their photoluminescence properties under near-ultraviolet (UV) irradiation were investigated. It was found that CaYP2O7.5: Eu3+ phosphor emits strong red light when excited by a radiation of 394-nm wavelength and SrYP2O7.5:Eu3+ gives intense orange light when excited by a radiation of 396-nm wavelength. Strong green emission for AY(1-x)P(2)O(7.5):Tb3+ is also observed under near-UV irradiation (378 nm). When compared with emission intensity from a standard YPO4:0.05Tb(3+), the emission from SrYP2O7.5:0.05Tb(3+) showed greater intensity values under the same excitation wavelength (378 nm). X-ray powder diffraction analysis showed that AYP(2)O(7.5) has xenotime-type structure.