Preparation and Photoluminescence of Single-Crystalline GdVO₄:Eu³⁺ Nanorods by Hydrothermal Conversion of Gd(OH)₃ nanorods

This paper reports a hydrothermal conversion process of a rare earth nanostructure, Gd(OH) 3 nanorods, into photoluminescent GdVO 4 nanorods, together with the investigation on the morphological changes and related photoluminescent properties. Gd(OH) 3 precursor with nanorod shape, uniform diameter, and good crystallinity was prepared by a colloidal hydrothermal method. High-resolution transmission electron microscopy (HRTEM) revealed the single-crystal nature of the precursor and preferred growth along the [001] direction. After hydrothermal conversion, well-crystallized GdVO 4 nanorods were obtained. The growth direction of the newly formed nanorods was also confirmed as [001] from HRTEM investigation. TEM observations of the nanorod samples hydrothermally treated for 4 and 8 h indicated that the nanorods were formed by a surface deposition with a subsequent crystal growth procedure, during which the VO 4 3− deposited onto the surface of the Gd(OH) 3 precursor and then reacted gradually with the inner core to generate the GdVO 4 nanorods. Such GdVO 4 nanorods showed strong red emission upon UV illumination when 5 at % Eu 3+ was doped into the lattice, due to the intrinsic Eu 3+ transition between 5 D 0 and 7 F j configuration, showing potential application of the nanorods in the photoluminescence field.