Improved thermal stability and luminescence properties of SrSi2O2N2:Eu2+ green phosphor by a heterogeneous precipitation protocol for solid-state lighting applications

Abstract

The SrSi2O2N2:Eu2+ green-emitting phosphor, as a member of oxynitride phosphors, could greatly enhance the color quality of the white-light conversed by single yellow-emitting phosphor. However, SrSi2O2N2:Eu2+ phosphors prepared by traditional solid-state ways normally consist hard agglomerates with unevenly dispersed particles and therefore suppress the luminescence properties. This research proposes a heterogeneous precipitation protocol where precipitation process is introduced, in order to produce a precursor in the first phase. And in the second phase, a high-temperature solid-state process is adopted for obtaining the final product. The main results show that, for an optimized SrSi2O2N2:Eu2+ phosphor prepared using our protocol, (1) the SrSi2O2N2:Eu2+ particles are faceted and with smooth faces and (2) the phosphor photoluminescence, external quantum efficiency, stability against thermal exposure, and physical stability consistently outperform the current commercially used product. This research essentially provides an economic way for production of solid-state lighting with enhanced color quality.