Controlled Synthesis of Tb(3+)/Eu(3+) Co-Doped Gd(2)O(3) Phosphors with Enhanced Red Emission

(Gd(0.93−x)Tb(0.07)Eu(x))(2)O(3) (x = 0–0.10) phosphors shows great potential for applications in the lighting and display areas. (Gd(0.93−x)Tb(0.07)Eu(x))(2)O(3) phosphors with controlled morphology were prepared by a hydrothermal method, followed by calcination at 1100 °C. XRD, FE-SEM, PL/PLE, luminescent decay analysis and thermal stability have been performed to investigate the Eu(3+) content and the effects of hydrothermal conditions on the phase variation, microstructure, luminescent properties and energy transfer. Optimum excitation wavelength at ~308 nm nanometer ascribed to the 4f(8)-4f(7)5d(1) transition of Tb(3+), the (Gd(0.93−x)Tb(0.07)Eu(x))(2)O(3) phosphors display both Tb(3+)and Eu(3+) emission with the strongest emission band at ~611 nm. For increasing Eu(3+) content, the Eu(3+) emission intensity increased as well while the Tb(3+) emission intensity decreased owing to Tb(3+)→Eu(3+) energy transfer. The energy transfer efficiencies were calculated and the energy transfer mechanism was discussed in detail. The lifetime for both the Eu(3+) and Tb(3+) emission decreases with the Eu(3+) addition, the former is due to the formation of resonant energy transfer net, and the latter is because of contribution by Tb(3+)→Eu(3+) energy transfer. The phosphor morphology can be controlled by adjusting the hydrothermal condition (reaction pH), and the morphological influence to the luminescent properties (PL/PLE, decay lifetime, etc.) has been studied in detail.