▎ 摘　　要

Sr2Si5N8:Eu2+ (258) phosphor has attracted much attention due to its excellent red emission properties. How-ever, its poor thermal stability hinders its further development in electronic display devices. Therefore, it is important to solve this problem in order to produce stable and long life-time WLED devices. In this work, a 258 phosphor was synthesized by a simple solid-phase reaction method, which was then coated by an ultrathin carbon layer by chemical vapor deposition. The carbon-coated powders were further annealed in N2 atmosphere at a high temperature to trigger the carbothermal reaction. On the one hand, the carbothermal reaction resulted in the removal of oxygen in the phosphor particle by a part of the carbon on the surface, which reduced the oxidation of both the luminescent centers and the host lattice. On the other hand, the remaining carbon crys-tallized, forming a graphene-like multilayer that protected the phosphor particle from the penetration of the external oxygen. This eventually resulted in a significant improvement of the thermal stability and oxidation resistance of the phosphor.