White light-generation phosphor Ba2Ca(BO3)(2): Ce3+, Mn2+ for light-emitting diodes

Ce3+ and Mn2+ co-doped Ba2Ca(BO3)(2) phosphors have been prepared at 950 degrees C under a reduced atmosphere, and their luminescence properties have also been investigated by tuning the concentration of activators. White light-emitting phosphors excited with UV or violet light could be obtained in Ce3+ and Mn2+ coactivated Ba2Ca(BO3)(2) phosphors by adjusting Mn2+ contents appropriately. Two types of Ce3+ centers, occupying the Ba2+[Ce3+(1)] and Ca2+[Ce3+(2)] sites, respectively, emit blue and green light, whereas the Mn2+ enters the Ca2+ sites and emits red light. The energy transfer involving Ce3+ (1) --> Ce3+ (2), Ce3+ (1) --> Mn2+, and Ce3+ (2) --> Mn2+ have also been observed by analyzing their photoluminescence (PL) and PL excitation spectra. The energy transfer efficiencies from different Ce3+ sites to Mn2+ were calculated by decline and growth of their emission relative intensity. In light of the principle of energy transfer and appropriate tuning of activator contents, we demonstrated that Ba2Ca(BO3)(2): Ce3+, Mn2+ is potentially useful as an UV or near- UV convertible phosphor for white light-emitting diodes. Moreover, their CIE chromaticity coordinates, color temperature, and color-rendering index Ra have also been calculated according to corresponding PL spectra under 345 and 395 nm radiation. (C) 2008 The Electrochemical Society.