Mehrnoosh Atashfaraz
National Iranian Oil Refining and Distribution Company, Iran
Title: Supercritical hydrothermal synthesis of amino-acid-displaying water-dispersible In2O3 nanocrystal and their optical properties
Biography
Biography: Mehrnoosh Atashfaraz
Abstract
Indium oxide (In2O3) nanoparticles were successfully synthesized via simple rapid hydrothermal method at 400 and 450C under pressures of 25 and 30 MPa within 10 min. It was found that the highest temperature (450C) and lowest pressure (25 MPa) condition was preferable to obtain pure cubic crystals of In2O3, because of the higher dehydration rate at 450C and lower water concentration at low pressure (25 MPa). Moreover, we succeeded in the synthesis of hydrophilic amino-acid-modified In2O3 nanoparticles by the same method at 450C and 25 MPa within 10 min. 5-Aminovaleric acid was used as the modifier. Changes in the surface properties of the nanoparticles by surface modification were observed by Fourier transform infrared spectroscopy, thermogravimetric analysis, zeta potential, and transmission electron microscopy (TEM), which demonstrated that the reagent chemically bound onto the surface of the In2O3 nanoparticles. The TEM images show that the morphology and size of the surface-modified nanoparticles were spherical with a diameter of 31 nm, respectively. The surface-modified nanoparticles were water dispersible; their isoelectric point shifted to a low pH range because of the nature of the carboxyl group contained in the structure. The synthesized unmodified and surface-modified In2O3 nanoparticles show a unique, wide-range blue–red light emission after excitation at 300 nm at room temperature. These results suggest that In2O3 nanoparticles could have significant potential for applications in optoelectronic devices.