Enhanced Red Light Photoluminescence of the Europium and Yttrium Co-Doped ITO Powders

Abstract

Eu3+-Y3+codoped tin-doped indium oxide (ITO) powders were fabricated by the sol-gel method. The doping concentration of Sn4+ ions was fixed at 10 mol%. According to the powder X-ray diffraction and X-ray photoelectron spectroscopy analyses, few Y3+ (≦2 mol%) ions can dissolve in Sn4+ (10 mol%)-doped In2O3 lattice to form YySnzIn2-y-zO3 solid solution but more Y3+ doping (>2 mol%) results in the segregation of excess Y3+ ions to form Y2O3. Therefore, the Eu3+-Y3+ (>2 mol%) codoped ITO powders are composed of a mixture of EuxYySnzIn2-x-y-zO3 and EuwY2-wO3 phases. The resulting Eu3+-Y3+codoped ITO powders exhibit enhanced red 611 nm emission (5D0→7F2 transition) by adding more Y3+ ions. The 5D0→7F2 transition corresponding to the f–f transitions of Eu3+ ions and the Eu-O charge transfer occur at the strong absorption of 467 and 237 nm, respectively. However, the conductivity of Eu3+-Y3+codoped ITO powders is deteriorated by the more addition of Y3+ ions due to the formation of more insulating Y2O3.