KCa2Mg2V3O12: A novel efficient rare-earth-free self-activated yellow-emitting phosphor

摘要

The development of efficient near-ultraviolet (near-UV) excitable inorganic phosphors is highly important for application in near-UV-pumped white light-emitting diodes (LEDs). Herein, we reported on a novel efficient rareearth-free yellow-emitting KCa2Mg2V3O12 vanadate phosphor. These phosphors were prepared by using a conventional high-temperature solid-state reaction method. Photoluminescence study revealed that KCa2Mg2V3O12 phosphor exhibited a broad excitation band in the 250 - 420 nm wavelength range with a peak at 346 nm, owing to the absorption of [VO4](3-) groups. Upon 346 nm excitation, KCa2Mg2V3O12 phosphor showed bright yellow emission in the 400 - 800 nm range with a maximum at 540 nm and a full width at half maximum of 161 nm. Such self-activated broadband yellow luminescence was attributed to the T-3(2) -> (1)A(1) and T-3(1) -> (1)A(1) transitions of [VO4](3-) groups. The Commission Internationale de l'Eclairage (CIE) color coordinates were calculated to be (0.3741, 0.4679), which were located in the yellow region in the CIE chromaticity diagram. Impressively, the internal quantum efficiency of KCa2Mg2V3O12 phosphor was measured to be as great as 41 %. In addition, the temperature-dependent emission spectra were recorded, and the activation energy E-a was determined to be 0.366 eV. The newly developed KCa2Mg2V3O12 phosphor might have application potential as color converter in white LEDs.