Hydrothermal synthesis and characterization of WO<sub>3</sub> nanostructures: Effect of reaction time
Fatemeh Shariatmadar Tehrani, Hamidreza Ahmadian, Maryam Aliannezhadi
Abstract
Abstract 1-D and 2-D WO 3 nanostructures were successfully prepared by hydrothermal technique as a low temperature, low cost, compatible with the environment, and powerful method with controllability of particle size, shape, and stoichiometry. The effect of hydrothermal duration time was studied to investigate morphological, structural and optical properties and to propose the possible growth mechanisms of WO 3 nanostructures. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and Diffuse reflectance spectroscopy (DRS) analyses were done on the samples synthesized at different hydrothermal duration times of 6, 12, 24, and 36 h. The results indicated that the morphology evolutions of nanostructures strongly depend on hydrothermal duration time and concentration of capping agents. Two crystal phase transitions in accordance with the morphology evolution were also observed. The absorption edge of the samples exhibited a blue- and then red-shift by increasing the reaction time. The bandgaps of the samples were almost independent of the reaction time and the samples were transparent in a wide range of the visible light region. So, they can be regarded as excellent candidates for optoelectronic devices.