Excitation wavelength-sensitive multi-colour fluorescence in Eu/Tb ions doped yttrium aluminium garnet glass ceramics

Eu/Tb doped yttrium aluminium garnet (YAG) glass ceramics, containing single phase of YAG micro-crystals with an excellent orientation (1 1 1) in the matrix, have been prepared by heat-treating lithium-yttrium-aluminium-silicate (LYAS) precursor glasses. A group of dynamic-colour white fluorescences with different colour temperatures are achieved in Eu/Tb codoped YAG glass ceramics, attributing to the simultaneous generation of three primary colour (RGB) emissions from Eu³⁺ (red), Eu²⁺ (blue), and Tb ³⁺ (green) by varying the UV radiation wavelength. The favourable bright white light with the colour coordinate (0.360, 0.308) close to the equal energy point is obtained under 365 nm excitation. These admirable results indicate that the Eu/Tb codoped YAG glass ceramics are a promising candidate to develop white light sources under the excitation of commercial UV-LEDs. © 2012 Elsevier B.V. All rights reserved.