Vacuum ultraviolet excitation and photoluminescence characteristics of (Y,Gd)Al3(BO3)4/Eu3+

Vacuum ultraviolet (VUV) excitation and photoluminescence (PL) characteristics of new red phosphors, YAl3(BO3)4/Eu3+ and Y0.65Gd0.35Al3(BO3)4/Eu3+ are studied. The VUV excitation spectra of both YAl3(BO3)4/Eu3+ and Y0.65Gd0.35Al3(BO3)4/Eu3+ are composed of two broad bands. One band with the absorption edge at ca. 168 nm is the band-gap absorption of aluminoborate and the other broad band centered at 240 nm is the charge transfer transition between Eu3+ and the neighboring oxygen anions. Rare earth ions are at the center of distorted trigonal prism, occupying non-centrosymmetric sites in the orthorhombic YAl3(BO3)4 lattices. The PL spectra of YAl3(BO3)4/Eu3+ and Y0.65Gd0.35Al3(BO3)4/Eu3+ show the strongest emission line at 617 nm due to the forced electric dipole 5D0→7F2 transition of Eu3+ ion, whose luminescent chromaticity coordinates are (0.67, 0.33).