Improvement of quantum efficiency through Gd3+ to Eu3+ energy transfer in YF3 phosphor.

This paper reports the energy transfer from Gd3+ to Eu3+ in YF3 and the consequent downconversion luminescence for the YF3 :Gd3+ , Eu3+ fluoride phosphor. The phosphor was synthesized using a soft chemical route, followed by a reactive atmosphere process. Because of the wide band gap in YF3 and the correct energy site for 8 S7/2 -6 GJ transitions of Gd3+ ions, fluoride YF3 doped with Gd3+ -Eu3+ were studied in their vacuum-ultraviolet (VUV) spectral regions. Powder X-ray diffraction (XRD) analysis showed the structural purity of YF3 . VUV excitation and emission properties were explored using a VUV synchrotron radiation beam line. Downconversion of energy from VUV (157 nm) to visible light with quantum efficiency c. 189% was seen. This YF3 :Gd3+ , Eu3+ phosphor would be an option for mercury-free fluorescence lamps.