Controlled growth of oxygen-deficient tin oxide nanostructures via a solvothermal approachin mixed solvents and their optical properties

Abstract

SnO2 nanostructures such as flower-like nanorod clusters, nanorods with arc or ringhierarchical structures, and individual nanorods were obtained via a solvothermalapproach in mixed solvents of ethylenediamine and distilled water. By justsimply adjusting growth parameters such as the volume ratio of the two kindsof solvents and dosage of NaOH, the size and hierarchical structures ofSnO2 crystalscould be easily varied. X-ray diffraction patterns revealed the as-prepared products to be pure tetragonalSnO2 with rutile structure. The energy-dispersive x-ray spectroscopy analysis displayed evidenceof nonstoichiometry, indicating that a high concentration of oxygen vacanciesexist in the nanorods. High-resolution transmission electron microscopy imagesrevealed that the obtained nanorods exhibited preferential growth along [] and many structural defects existed in the nanorods. The crystal growth mechanism of theSnO2 nanostructures is discussed. Their size-dependent optical properties including UV–visabsorption spectra and room-temperature photoluminescence spectra were alsostudied.