Luminescent Properties of Gd 3 PO 7 :Eu in UV/VUV Region

Abstract

The luminescent properties of Gd₃PO₇:Eu were investigated in UV and VUV regions. This phosphor has such strong emissions around 618.5 nm under UV excitation, especially around 209 nm, that it has a better colour saturation than that of Y₂O₃:Eu. It could be a new potential red phosphor for lamp and other applications with UV-excitation source or even for displaying devices. In the VUV excitation spectrum of Eu³⁺ emissions, energy absorptions by Gd³⁺, Gd-O and PO₄^3- have been observed, on which it can be inferred that there are three kinds of energy transferring processes to Eu³⁺ ions. The energy absorptions of Gd³⁺, Gd-O and PO₄^3- are induced by 4f→4f transitions, a bandgap transition of Gd₃PO₇ and intramolecular (2t₂→2a, 3t₂) transition, respectively. The energy transfer efficiency of the PO₄^3- intramolecular transition is lower compared with that of the bandgap transition (Gd-O).