Novel orange-emitting Ba2LaNbO6:Eu3+ nanophosphors for NUV-based WLEDs and photocatalytic water purification

Abstract

Energy conservation and environmental safety are the key requirements in the modern world. We report novel orange-emitting double perovskite Ba2LaNbO6:Eu3+ (BLN:Eu3+) nanophosphor fabricated using a citrate sol-gel method for use in general illumination and photocatalysis. After annealing at 800 degrees C, the particles exhibited a nanorod-like morphology with monoclinic structure. The photoluminescence emission spectra exhibited an intense D-5(0) -> F-7(1) transition at 594 nm and a moderate D-5(0) -> F-7(2) transition at 615 nm, demonstrating that the Eu3+ ions occupied the La3+ sites with inversion symmetry. The optimal concentration of Eu3+ ions was found to be about 5 mol% for the BLN host lattice. Energy transfer from the NbO67 octahedrons to the Eu3+ ions was clearly witnessed when the BLN:Eu3+ nanophosphors were excited with both the characteristic excitation bands of Eu3+ (F-7(0) -> L-5(6)) and NbO67- octahedrons at 392 and 380 nm, respectively. The thermal quenching temperature of 5 mol% Eu3+ ions doped BLN nanophosphors was found to be 183 degrees C, indicating that these nanophosphors are very stable at high temperatures. In addition, the dye removal efficiency of the proposed BLN nanophosphors was verified using Rhodamine B (RhB) dye as a model pollutant under UV irradiation. Compared to a commercial nano-ZnO catalyst, our synthesized BLN nanophosphors showed superior RhB de-colorization efficiency. Therefore, the proposed BLN:Eu3+ nanophosphors are promising multifunctional materials for photocatalysis and general lighting applications.