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

Ce3+ and Mn2+ co-doped Ba2 Ca (B O3)2 phosphors have been prepared at 950°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 Ba2 Ca (B O3)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 Ba2 Ca (B O3)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.