Photoluminescence properties of Eu2+ and Mg2+ co-doped CaSi2O2N2 phosphor for white light LEDs

CaSi2O2N2:Eu, Mg phosphors have been synthesized through the conventional high temperature solid-state reaction method. The effect of Mg2+ doping on the structure and photoluminescence (PL) properties of CaSi2O2N2:Eu, Mg was investigated systematically. The results reveal that the phosphor retains the CaSi2O2N2 single phase, with the lattice expanding upon increasing the Mg2+ concentration, in an appropriate range. The average size of CaSi2O2N2:Eu, Mg phosphor is 3–8 μm. At a certain concentration, doping Mg2+ ions can greatly enhance the absorption and PL intensity of CaSi2O2N2:Eu, Mg phosphors. The temperature dependent luminescence measurements show that the thermal quenching remains small in the case of Mg2+ doping, in other word, Eu2+/Mg2+ co-doped phosphor has a good thermal stability. Furthermore, the quenching concentration of Eu2+ in phosphors can also be increased by doping Mg2+. Therefore, this novel CaSi2O2N2:Eu, Mg phosphor is promising for white light emitting diodes (white-LEDs).