Improving Quantum Efficiency and Thermal Stability in Blue-Emitting Ba 2– x Sr x SiO 4 :Ce 3+ Phosphor via Solid Solution

Ba 1.8– x Sr x SiO 4:0.1Ce 3+,0.1Na + ( x = 0–1.8) phosphors were prepared by a high-temperature solid-state reaction. The emission peaks of Ba 1.8– x Sr x SiO 4:0.1Ce 3+,0.1Na + shift from 391 to 411 nm with increasing Sr 2+ content under excitation by a UV light at around 360 nm. Ba 0.4 Sr 1.4 SiO 4:0.1Ce 3+,0.1Na + phosphor exhibits the best performance of luminescence, whose absolute quantum efficiency is 97.2%, and the emission intensity at 150 °C remains 90% of that at room temperature. The effect of replacing Ba 2+ by Sr 2+ on the red shift of the emission band and the increase of quantum efficiency (QE) and thermal stability (TS) was investigated in detail based on the Rietveld refinements, Raman spectra, thermoluminescence, and decay curves, etc. The performance of UV chip-based pc-LEDs indicates that Ba 0.4 Sr 1.4 SiO 4:0.1Ce 3+,0.1Na + can be a promising blue phosphor for white-emitting pc-LEDs.