Photoluminescence and phosphorescence properties of Sr1-xZn2-y(PO4)2:Eux2+,Mny2+ phosphor for UV-based white-LEDs

Sr1-xZn2-y(PO4)2:Eux2+,Mny2+ (SZP: Eux2+,Mny2+) phosphors (x=0, 0.01 and y=0, 0.01) were prepared by using a stoichiometric solid-state reaction method and their photoluminescence and phosphorescence decay properties were investigated. The emission spectrum of SrZn2(PO4)2:Eu0.012+, Mn0.012+ measured under 400 nm excitation was composed of the violettish blue and the emerald green emissioins centered at 421 and 547 nm, respectively. The excitation wavelength of the emission peak at 547 nm was about 421 nm in the excitation spectrum of SZP:Mn0.012+. Since, this value is equal to the transition energy of Eu2+, the energy transfer from Eu2+ to Mn2+ in SZP:Eu0.012+,Mn0.012+ phosphor has been demonstrated. The CIE chromaticity coordinates of SZP:Eu0.012+,Mn0.012+ phosphor were (0.330, 0.328) under the excitation wavelength 375 nm at room temperature. The phosphorescence from SZP:Eu0.012+,Mn0.012+ could be seen by naked eyes for few seconds and it has persisted for about 4.4 h while monitoring by using a PMT spectrometer. Therefore, SZP:Eux2+,Mny2+phosphor may be a potential candidate for the UV-based white light-emitting diodes (LEDs).