Tunable single-phase white-light-emitting Ba2Mg(BO3)2:Ce3+, Na+, Tb3+, Eu2+ phosphor based on energy transfer

A series of white-light-emitting phosphors of single-phase Ba2Mg(BO3)2:Ce3+, Na+, Tb3+, Eu2+ were synthesized by conventional solid-state reaction. The crystal structure of the host was characterized by X-ray diffraction and investigated by Rietveld refinement. Photoluminescence properties were studied in detail. The energy transfer from Ce3+ to Tb3+ in Ba2Mg(BO3)2 host was investigated and demonstrated to be a resonant type via a quadrupole-quadrupole mechanism. White light with wavelength tunable was realized by coupling the emission bands peaking at 417, 543 and 626 nm attributed to Ce3+, Tb3+ and Eu2+, respectively. By properly tuning the relative composition of Ce3+(Na+)/Tb3+/Eu2+, optimized Commission Internationale de l׳Eclairage (CIE) chromaticity coordinates (0.363, 0.295), high color rendering index (CRI) 90 and low correlated color temperature (CCT) 3793 K were obtained from the phosphor of Ba1.90Ce0.04Na0.04Eu0.02Mg0.94Tb0.06(BO3)2 upon the excitation of 296 nm UV radiation. These results indicate that Ba2Mg(BO3)2:Ce3+, Na+, Tb3+, Eu2+ phosphor has a potential application as an UV radiation down-converting phosphor in white-light-emitting diodes.