Origin of White Luminescence in Ag-Eu Co-doped Oxyfluoride Glasses

Abstract

A combination of red, green and blue emissions has emerged to achieve pure white emission (X = 0.323, Y = 0.320) in Ag-Eu co-doped oxyfluoride glasses. The type of luminescent species, the origin of white emission and the enhancement mechanism for red and blue emissions were investigated by means of absorption, emission and excitation spectra, decay lifetime measurements, as well as time-resolved spectroscopy. Results prove that white emission is originated from f-f transitions of Eu3+ (red), ML-Ag (very small molecule-like, non-plasmonic Ag particles, green) and 5d-4f transition of Eu2+ (blue). Our researches show that Ag-Eu co-doped glasses may provide a new platform to design and fabricate novel phosphors for ultraviolet light-emitting diode (LED) chips.