Size-Tailored Synthesis and Luminescent Properties of One-Dimensional Gd2O3:Eu3+ Nanorods and Microrods

Nearly monodisperse and well-defined one-dimensional (1D) Gd2O3:Eu3+ nanorods and microrods were successfully prepared through a large-scale and facile hydrothermal method followed by a subsequent heat treatment process, without using any catalyst or template. X-ray diffraction (XRD), thermogravimetric analysis and differential scanning calorimetry (TGA−DSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), photoluminescence (PL) and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples. The size of the Gd2O3:Eu3+ rods could be modulated from micro- to nanoscale with the increase of pH value using ammonia solution. The as-formed product via the hydrothermal process, Gd(OH)3:Eu3+, could transform to cubic Gd2O3:Eu3+ with the same morphology and a slight shrinking in size after a postannealing process. The formation mechanism for the Gd(OH)3 rods has been proposed. Both the Gd2O3:Eu3+ nanorods and microrods exhibit the same strong red emission corresponding to 5D0 → 7F2 transition (610 nm) of Eu3+ under UV light excitation (257 nm) and low-voltage electron beam excitation (1−5 kV), which have potential applications in fluorescent lamps and field emission displays.