Preparation and luminescence properties of SrSi2O 2N2:Eu2+ phosphors for white LEDs

Abstract

This work has investigated luminescence properties of SrSi 2O2N2: Eu2+ phosphors synthesized by a new method using Sr2SiO4: Eu2+ as a precursor. Compared with a conventional solid-state reaction method, this method provides increased crystallinity and luminescence efficiency. X-ray diffraction analysis has indicated that SrSi2O2N2: Eu 2+ formed as an almost single-phase, but chemical analysis has shown that obtained samples have an oxygen/ nitrogen atomic ratio deviated from the stoichiometric composition. It can be expected that luminescence efficiency of this phosphor will be higher for the stoichiometric composition than for non-stoichiometric ones. Under 460 nm excitation, this phosphor shows an emission band peaked at 538-564 nm for varied Eu2+ concentration, and shows the maximum at 15 mol% with high integrated photoluminescence intensity, which is about 1.05 times as high as that of the commercial yellow phosphor, (Y,Gd)3Al5O12: Ce3+ (P46-Y3).