Identification of charge transfer (CT) transition in (Gd,Y)BO3 : Eu phosphor under 100-300nm

摘要

A broad excitation band in an excitation spectrum of (Gd,Y)BO3:Eu was observed in the VUV region. It could be considered that this band was composed of two bands at about 160 and 166 nm. The preceding band was assigned to the BO3 group absorption. The later one at about 166 nm could be assigned to the charge transfer (CT) transition of Gd3+-O2-. Such an assignment was deduced from the result that broadbands at around 170 nm for GdAlO3:Eu, and at 183 mn for Gd2SiO5:Eu are due to the CT transition of Gd3+-O2-; this was also identified by CaZr (BO3)(2):Eu. Since there are no Gd3+ ions in it; a weak band in the VUV region in the excitation spectrum of Ca0.95ZrEu0.05(BO3)(2) was observed. The excitation spectra were overlapped between the CT transition of Gd3+-O2- and BO3 group absorption, and it caused the emission of Eu3+ effectively in the trivalent europium-doped (Gd,Y)BO3 host lattice under 147 nm excitation. Intense broad excitation bands were observed at about 155 nm for YBO3:Eu and at about 153 nm for YAlO3:Eu; it could be attributed to the CT transition between y(3+) and O2-. As a result, under the xenon discharge (147 nm) excitation, the intense emission of Eu3+ in GdBO3 was found to be more convenient just because of the partial substitution of Y3+ for Gd3+. (C) 2004 Elsevier Inc. All rights reserved.