Highly symmetric lattice environment induced orange-red emitting of Eu3+ in a novel tungstate phosphor with broad-band ultraviolet excitation

In this work, we reported the synthesis and characteristic luminescence of an orange-red emitting phosphor NaBa 10 Y 5 W 4 O 30 : Eu 3+ for ultra-violet white light emitting diodes. The phase compound, crystalline structure and morphology are analyzed. The results indicate that a heavy doping of Eu 3+ ( x  = 50%) is realized in NaBa 10 Y 5-5 x W 4 O 30 : x Eu 3+ without any impurity phase. Moreover, the optical band gap is analyzed by diffuse reflectance spectroscopy and further confirmed by density function theory (DFT). Meanwhile, the as-synthesized NaBa 10 Y 5 W 4 O 30 : Eu 3+ phosphor can be efficiently pumped by strong broad-band excitation around 315 nm due to the charge transfer transition from [WO 6 ] 6- groups to Eu 3+ . Owing to the highly symmetric lattice environment of Eu 3+ in YO 6 sites, a strong orange-red emission at 596 nm with color purity of 95.34% is obtained, corresponding to the 5 D 0 → 7 F 1 magnetic dipole transition of Eu 3+ ions. The critical concentration is obtained to be  x  = 15%, and the quenching mechanism is discussed to be dipole–dipole interaction. Furthermore, the temperature dependent emission behavior are analyzed, and the thermal quenching mechanism are explained by the variable temperature decay curve and configuration coordination diagram. Finally, an orange-red light emitting diode lamp is fabricated based on NaBa 10 Y 5 W 4 O 30 : 15%Eu 3+ phosphor and 315 nm semiconductor chip. In summary, the results indicate that NaBa 10 Y 5 W 4 O 30 : Eu 3+ phosphor has the potential to be an orange-red phosphor for white light emitting diodes.