(Gd0.93-xTb0.07Eux)₂O₃ (x = 0⁻0.10) phosphors shows great potential for applications in the lighting and display areas. (Gd0.93-xTb0.07Eux)₂O₃ 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 Eu3+ 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 4f⁸-4f⁷5d¹ transition of Tb3+, the (Gd0.93-xTb0.07Eux)₂O₃ phosphors display both Tb3+and Eu3+ emission with the strongest emission band at ~611 nm. For increasing Eu3+ content, the Eu3+ emission intensity increased as well while the Tb3+ emission intensity decreased owing to Tb3+→Eu3+ energy transfer. The energy transfer efficiencies were calculated and the energy transfer mechanism was discussed in detail. The lifetime for both the Eu3+ and Tb3+ emission decreases with the Eu3+ addition, the former is due to the formation of resonant energy transfer net, and the latter is because of contribution by Tb3+→Eu3+ 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.
Keywords: Gd2O3:Tb3+/Eu3+; energy transfer; hydrothermal method; luminescent properties.