Photoluminescence properties and energy-transfer of thermal-stable Ce3+, Mn2+-codoped barium strontium lithium silicate red phosphors

A series of thermal-stable Ce3+, Mn2+-codoped barium strontium lithium silicate (BSLS) phosphors was synthesized by a high-temperature solid-state reaction. The XRD patterns of this phosphor seem to be a new phase that has not been reported before. BSLS:Ce3+, Mn2+ showed two emission bands under 365 nm excitation: one observed at 421 nm was attributed to Ce3+ emission, and the other found in red region was assigned to Mn2+ emission through Ce3+–Mn2+ efficient energy transfer. The Mn2+ emission shifted red along with the replacement of barium by strontium, which was due to the change of crystal field. A composition-optimized phosphor, BSLS:0.10Ce3+, 0.05Mn2+ (Ba = 65), exhibited strong and broad red-emitting and supreme thermal stability. The results suggest that this phosphor is suitable as a red component for NUV LED or high pressure Hg vapor (HPMV) lamp.

Research highlights▶ Excited by UV, strong red luminescence is observed from Ce3+, Mn2+-codoped barium strontium lithium silicate (BSLS), while violet-blue emission from Ce3+ sole doped BSLS. ▶ These results indicate the Mn2+-derived red emission is originated by an efficient Ce3+ → Mn2+ energy transfer. ▶ The red emission becomes stronger with increased Sr content, and shows red-shift. ▶ These phosphors demonstrate good thermal stability even in 180 °C, which is suitable for NUV LED application.