Eu3+-activated Sr3LaNb3O12 red-emitting phosphors with excellent color stability for high color rendering w-LEDs

A novel red-emitting phosphor Sr3LaNb3O12:Eu3+ with triclinic perovskite structure was first synthesized via the high-temperature solid-phase method. The phase purity, crystallinity, surface morphology, thermal quenching, and luminescent properties of the Sr3LaNb3O12:xEu(3+) (x = 0.01-0.50 mol) phosphors were characterized. At 395-nm excitation, Sr3LaNb3O12:Eu3+ phosphor emits the strongest peak at 612 nm, ascribed to the transitions of D-5(0)-> F-7(2) by Eu3+ ions. The critical energy transfer distance and optimal doping concentration of Eu3+ ions are 11.87 angstrom and 0.30 mol, respectively. The relative initial intensity of Sr3LaNb3O12:0.30Eu(3+) just drops to 78.3% at 420 K, and the thermal quenching temperature (T-0.5) is above 480 K. By calculation, the activation energy (E-a) is 0.21 eV, and the color purity of all samples is between 99.5% and 99.8%. A white light-emitting diode (w-LED) with the chromaticity coordinates of (0.331, 0.349), a good correlated color temperature (CCT) of 5451 K, and a color rendering index (R-a) of 94 was successfully fabricated. In consequence, the feasibility of niobate red-emitting Sr3LaNb3O12:Eu3+ phosphor for the white light-emitting diode was unveiled.