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The luminescence of the vanadate garnet, Ca2NaMg2normalV3normalO12 , activated with trivalent europium is evaluated and discussed as a potential ultraviolet light-emitting diode (UV-LED) phosphor. This single phosphor is capable of converting the ultraviolet emission of a UV-LED into white light with good luminosity and color-rendering index. We have evaluated the luminescence of this material at elevated temperatures, because the junction temperatures of typical LEDs can be greater than 100°C . There is significant thermal quenching of this phosphor and emission color shift at T100°C . This is attributed to energy migration and transfer to nonradiative traps and Eu3+ within the host lattice. These implications on the use of this phosphor in UV-LED based light sources is also discussed.

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The deep red luminescence of Mn" in the distorted perovskite Gd2MgTiO6 is reported and discussed. The excitation spectrum of Mn" luminescence is dominated by the 02-to Mn4' charge-transfer transition at -31,700 cm'. The luminescence is due to the 2E -4A2 transition with the zero-phonon line at -14,685 cm' and the associated side bands at longer wavelengths. Evidence is presented for the occurrence of multiple Mn" sites in the host lattice. This is attributed to the deviation from a perfect 1:1 order between the B-site ions (Mg2/Ti") of the perovskite lattice. The unactivated host lattice also exhibits Mn" luminescence due to the presence of this ion as an