Efficiency and Thermal Stability Enhancements of Sr2SiO4:Eu2+ Phosphor via Bi3+ Codoping for Solid-State White Lighting

Abstract

Bi and Eu-codoped yellow-emitting phosphors of composition Sr1.95-xEu0.05BixSiO4 were prepared, and their emission and thermal quenching characteristics were investigated. The initial PL intensity and thermal quenching behaviors of Sr1.95-xEu0.05BixSiO4 were affected by the Bi-codoping as a coactivator. When 0.01 mol% of Bi was codoped to Sr1.95-xEu0.05BixSiO4, it showed an intense emission peak at 543nm under 450nm excitation. The peak intensity corresponds to a relative intensity of 112% of a commercial Sr2SiO4:Eu2+ phosphor (Force4 Corp.), which may be attributed to energy transfer between Bi3+ and Eu2+. The results suggest that phosphors deriving from Sr1.95-xEu0.05BixSiO4 will be a breakthrough for white light emitting diode (LEDs) and related applications in terms of efficiency enhancement and thermal stability. (C) 2012 The Japan Society of Applied Physics