First observation of 5DJ (J=1, 2, 3) emission transitions in Eu3+-activated rare-earth antimony garnet R3Sb5O12 (R=Y, Gd, La)

R2.9Eu0.1Sb5O12 (R=Y, Gd, La) polycrystalline powders were prepared by solid-state reaction and characterized by X-ray powder diffraction (XRD), photoluminescence, decay lifetimes, and CIE color coordinates. The phosphors can be efficiently excited by UV-light and presents the emission covering the entire visible spectrum. Except for the commonly reported 5D0-7F0,1,2,3,4 transitions of Eu3+ ions in R2.9Eu0.1Sb5O12 (R=Y, La), higher 5D1,2,3 states present stronger emission lines. This produces white emission in the single-phased phosphor, whereas R2.9Eu0.1Sb5O12 (R=Gd) shows orange emission due to the absence of 5D3,2 transitions. The emission mechanism from the high-energy levels of 5D1,2,3 Eu3+ ion in R2.9Eu0.1Sb5O12 (R=Y, Gd, La) phosphors is also discussed.