High-performance red@green core-shell emitting nitride phosphor with monodisperse Eu2+ luminescence centers for solid state lighting

Abstract

The red@green core-shell emitting phosphor with monodisperse luminescence center was successfully constructed by Eu2+ doped Sr2Si5N8 and Sr2Si5N8@SrSi2O2N2 via a deposition-precipitation (DP) method. Compared to traditional solid state reaction (SSR) method, under excitation at 370 nm, Sr2Si5N8:0.05Eu2+ phosphor prepared by DP method exhibits red emission at 611 nm and an ~1.4-fold luminescent intensity enhancement. Interestingly, upon near-ultraviolet (NUV) excitation, Eu2+ doped Sr2Si5N8@SrSi2O2N2 phosphors prepared by DP method exhibit a dual emission feature with the green emission at 538 nm and red emission peak at 611 nm. The elemental line scanning spectrum of the energy dispersive X-ray analysis indicates a core@shell structure of Sr2Si5N8@SrSi2O2N2. Furthermore, this red@green core-shell emitting phosphor can be encapsulated in ultra-low melting Sn-F-P-O glass to achieve the white light with excellent color quality Ra = 85) and low correlated color temperature (4484 K) when pumped by near ultraviolet LED chips.