(152645)Site occupancy and tunable photoluminescence properties of Eu~(2+)-Activated Ba_3Sc(BO_3)_3 phosphors for white light emitting diodes

摘要

A series of emission-tunable Ba_(3-x)Sc(BO_3)_3: xEu~(2+) (0 ≤ x ≤ 0.15) and Ba_(2.97-y)Gd_ySc_(1-y)Mg_y(EO_3)_3: 0.03Eu~(2+) (0 ≤y ≤ 0.15) phosphors were synthesized by a solid-state method. Structure analysis of X-ray powder diffraction (XRD) and Rietveld refinement show that Eu~(2+) ions occupy randomly at Ba sites of hexagonal lattice with space group P6_3cm. Photoluminescence emission spectra and the decay curves of phosphors demonstrated the existence of multiple Eu~(2+) emitting centers. Eu~(2+) ions occupy at four Ba sites of Ba_(3-x)Sc(BO_3)_3: xEu~(2+) (0.03 ≤x≤0.15) emit orange light (λem = 670nm and 560nm) through 370nm UV excitation. The broader absorption band, ranging from 220 nm to 550 nm, matches well with the near-ultraviolet LED chips. Furthermore, color tuning from orange to red is successfully achieve by the double doping of Gd~(3+)-Ba~(2+) and Mg~(2+)-Sc~(3+) in Ba_(2.97)Sc(BO_3)_3: 0.03Eu~(2+). Our results indicate that red emission Ba_3Sc(BO_3)_3: Eu~(2+) phosphors is an ideal candidate for the application in white light-emitting diodes.