Photoluminescence properties of Eu 2+ and Mn 2+-activated BaMgP 2O 7 as a potential red phosphor for white-emission

Abstract

A phosphate compound, BaMgP 2O 7 was co-doped with Eu 2+ and Mn 2+ for making a red-emitting phosphor. The phosphor was prepared by a solid-state reaction at high temperature. The photoluminescence properties were investigated under ultraviolet (UV) ray excitation. From a powder X-ray diffraction (XRD) analysis, the formation of single-phased BaMgP 2O 7 with a monoclinic structure was confirmed. In the photoluminescence spectra, the BaMgP 2O 7:Eu,Mn phosphor emits two distinctive colors: a blue band centered at 409 nm originating from Eu 2+ and a red band at 615 nm caused by Mn 2+. Also, efficient energy transfer from Eu 2+ to Mn 2+ in the BaMgP 2O 7:Eu,Mn system was verified by observing that the excitation spectra of BaMgP 2O 7:Eu,Mn emitted at 409 and 615 nm by Eu 2+ emission and Mn 2+ emission, respectively, are almost the same as that of BaMgP 2O 7:Eu monitored at 409 nm. The optimum concentration of Eu 2+ ions in BaMgP 2O 7:0.015Eu excited at 309 nm wavelength is 1.5 mol%. With an increase of Mn 2+ content up to 17.5 mol%, a systematic decline in the intensity of the excitation spectrum by Eu 2+ and a gradual growth in the intensity of emission band by Mn 2+ were observed. Accordingly, the optimum concentration of Mn 2+ in BaMgP 2O 7:0.015Eu,Mn is 17.5 mol%. The maximum spectral overlap between emission of Eu 2+ and excitation of Mn 2+ is achieved in a composition of BaMgP 2O 7:0.015Eu,0.175Mn, resulting in considerable red-emission at 615 nm.