Improvement of quantum efficiency through Gd 3+ to Eu 3+ energy transfer in YF 3 phosphor

This paper reports the energy transfer from Gd 3+ to Eu 3+ in YF 3 and the consequent downconversion luminescence for the YF 3 :Gd 3+ , Eu 3+ fluoride phosphor. The phosphor was synthesized using a soft chemical route, followed by a reactive atmosphere process. Because of the wide band gap in YF 3 and the correct energy site for 8 S 7/2 – 6 G J transitions of Gd 3+ ions, fluoride YF 3 doped with Gd 3+ −Eu 3+ were studied in their vacuum–ultraviolet (VUV) spectral regions. Powder X‐ray diffraction (XRD) analysis showed the structural purity of YF 3 . 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 YF 3 :Gd 3+ , Eu 3+ phosphor would be an option for mercury‐free fluorescence lamps.