Enhancing thermal stability and photoluminescence of red-emitting Sr2Si5N8:Eu phosphors via boron doping

Abstract Surface passivation is a common method to improve the resistance of thermal degradation of nitride phosphors. However, such a surface passivation generally needs extra processes and decreases the photoluminescence property of the phosphors. In this work, both the thermal stability and photoluminescence property of a red phosphor Sr2Si5N8:Eu are improved through the addition of BN. The influence of B on the crystal structure and the valence state of active ions was analyzed by experimental characterization. First-principles calculations were applied to analyze the formation energy of N vacancies, which influence the resistance of thermal degradation. Finally, combining with experimental characterization and calculations, the enhancing mechanism of thermal stability and photoluminescence by B was studied.