Synthesis of CaSi2O2N2 : Eu LED-Phosphors from Reactive Spherical Templates with Hollow Structures

Abstract

Efficient oxonitridosilicate phosphors for application in phosphor-converted light emitting diodes (LEDs) were synthesized from a core–shell template precursor using gas as a reduction–nitridation agent. Scanning electron microscopy images show that the spherical shape of the reactive template was imprinted in the resulting material, and pores were formed during the nitridation process. Thermogravimetric analysis and nitrogen sorption measurements confirmed that the decomposition of the carbonates promoted the formation of the porous structures, which supplied sufficient interface with the gas. Thus, the desired nitridosilicate phosphors were obtained at relatively low temperatures of around , and the reaction time was significantly shortened to 1 h. The phosphors prepared by this route exhibited better photoluminescence properties compared to those of the conventionally prepared powder.