Oriented attachment (OA) mediated characteristic growth of Gd2O3 nanorods from nanoparticle seeds

Herein, we demonstrated the oriented attachment (OA) driven formation and characterization of Gd2O3 nanorods. The nanorods were synthesized via a surfactant free, inexpensive hydrothermal route and considering ∼30 nm nanoparticles as the seed. While maintaining a cubic phase throughout the process, complete transformation of Gd2O3 nanoparticles to nanorods was found to occur at an elevated temperature (∼180 °C) of the hydrothermal reaction. The elongated Gd2O3 nanostructures, as revealed from transmission electron microscopic imaging, possessed an average diameter of ∼33 nm and an approximate length of 172 nm. From the kinetics of OA process, the activation energy of formation was estimated to be ∼25 kJ/mole. The existence of defect mediated radiative emission was ascertained from the asymmetric broadening of luminescence spectra. The defect emission arising from the Gd2O3 nanorods was nearly 1.4 times stronger than that of nanoparticles. The morphological evolution and growth kinetics were discussed along with the luminescence and electron paramagnetic resonance features.

Graphical Abstract(a) Schematic growth mechanism of Gd2O3 nanorods (upper panel); (b) A set of TEM images illustrating transformation of nanoparticle seeds to nanorods through oriented attachment (lower panel)Figure optionsDownload as PowerPoint slide