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

Bi and Eu-codoped yellow-emitting phosphors of composition Sr 1.95-x Eu 0.05 Bi x SiO 4 were prepared, and their emission and thermal quenching characteristics were investigated. The initial PL intensity and thermal quenching behaviors of Sr 1.95-x Eu 0.05 Bi x SiO 4 were affected by the Bi-codoping as a coactivator. When 0.01 mol % of Bi was codoped to Sr 1.95-x Eu 0.05 Bi x SiO 4 , it showed an intense emission peak at 543 nm under 450 nm excitation. The peak intensity corresponds to a relative intensity of 112% of a commercial Sr 2 SiO 4 :Eu 2+ phosphor (Force4 Corp.), which may be attributed to energy transfer between Bi 3+ and Eu 2+ . The results suggest that phosphors deriving from Sr 1.95-x Eu 0.05 Bi x SiO 4 will be a breakthrough for white light emitting diode (LEDs) and related applications in terms of efficiency enhancement and thermal stability.