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

摘要

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 D-5(0)-F-7(0,1,2,3,4) transitions of Eu 3+ ions in R2.9Eu0.1Sb5O12(R = Y, La), higher D-5(1,2,3) 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 D-5(3,2) transitions. The emission mechanism from the high-energy levels of D-5(1,2,3) Eu3+ ion in R2.9Eu0.1Sb5O12 (R = Y, Gd, La) phosphors is also discussed.