Red-Emitting Phosphor Ba9Lu2Si6O24:Ce3+,Mn2+ with Enhanced Energy Transfer via Self-Charge Compensation

A new red-emitting phosphor, Ce3+–Mn2+ codoped Ba9Lu2Si6O24 was synthesized by using solid-state reactions. The phase formation, luminescence properties, energy transfer mechanisms, and thermal stabilities were investigated. Under the near-ultraviolet excitation, Ba9Lu2Si6O24:Ce3+,xMn2+ shows a tunable emission from blue-violet to red. When x = 0.08, the photoluminescence characterized a major peak at 610 nm with an internal quantum efficiency of about 70%. The energy transfer from Ce3+ to Mn2+ was further enhanced by self-charge compensation as a result of the presence of activators at different crystallographic sites simultaneously. At 160 °C, the quantum efficiency retained 84% of that measured at room temperature. The small thermal quenching and efficient luminescence suggest that Ba9Lu2Si6O24:Ce3+,Mn2+ is a promising candidate for use in ultraviolet chip pumped light-emitting diodes (LEDs).