Surface passivation of applying a thin carbon coating toward significantly thermal stable SrSi2O2N2: Eu2+ green phosphors

Abstract A lot of efforts have been devoted to improving the stability of phosphors. Due to the high stability and high transmittance of graphene material, we deposited a thin carbon layer on the surface of SrSi2O2N2: Eu2+ phosphor particles by chemical vapor deposition method as to improve its thermal and chemical stability. Chemical composition and microstructure of the coated particles were characterized and analyzed in detail. After coating, the carbon was attached on the phosphor in an amorphous form. The carbon coating alleviated the oxidation of Eu2+, which enhanced the luminous stability and extended the service time of the phosphors. The results showed that the carbon-coated phosphors better retained luminescence intensity at high temperatures. In addition, its oxidation resistance and thermal stability of fabricated LED had also been improved. Therefore, applying carbon coating on the phosphor is an effective way to improve the luminous stability of the phosphor.