Transmission electron microscopy study of Eu-doped Y₂O ₃ nanosheets and nanotubes

A hydrothermal method was used to synthesize high-purity Eu-doped Y ₂O₃ nanosheets and nanotubes with an approximate molar ratio of (0.1):(1.0) for Eu:Y. High-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy analysis and synchrotron X-ray diffraction were used to characterize these nanomaterials. A body-centered cubic structure was confirmed for the nanotubes. The lattice parameter of Eu-doped Y ₂O₃ nanotubes were 0.12% larger as compared to that of pure Y₂O₃ which was attributed to the larger ionic radius of Eu³⁺ (0.947 Å) than that of Y³⁺ (0.900 Å). The nanosheets had a similar structure. Nanosheets of approximate dimensions 600 to 800 nm length and width were obtained using a slightly lower pH value, and they were highly textured. The high resolution transmission electron microscopy images showed that the nanotubes are fully crystalline. The nanotubes were typically 1.5-3 μm in length and 50-200 nm in diameter. Using a pH value of approximately 10, stable nanotubes were obtained. It is anticipated that nanosheets might have rolled to form more stable nanotubes.