Luminescent properties of YNbO4 : Bi phosphors

Yttrium niobate doped with Bi was prepared using a solid-state reaction tec hnique and its luminescence behavior was investigated under ultraviolet and low-voltage electron excitations and with the first-principle calculations . The optimization of the photo- and cathodoluminescent properties was stud ied with control of Bi amounts and Y/Nb ratios. It was found that the lumin ance of YNbO4:Bi phosphors depends on the calcining conditions, Bi content, and particularly on the Y/Nb ratio. 0.2 wt % Bi3+-doped YNbO4 phosphors wi th a Y/Nb ratio of 52/48 showed the maximum emission intensity. The lumines cent properties of YNbO4 and YNbO4:Bi phosphors were interpreted with the c alculated density of states (DOS) using density functional theory. From the calculated DOS, we were able to explain the charge transfer gap in the hos t and the effect of Bi in the excitation and emission spectra. (C) 2000 The Electrochemical Society. S0013-3651(99)11-059-0. All rights reserved.