Effect of Crystallinity on Near Infrared Reflectance of Indium TiN Oxide Nanorice-Particles

Abstract

Tin-doped indium oxide or indium tin oxide (ITO) has many promising uses in applications, such as, transparent conductive oxides, flat panel displays, and energy-saving windows. In this work, nanorice particles of tin-doped indium oxide (ITO) were obtained by a simple sol-gel method. Indium salts and stannous fluoride precursors were mixed ultrasonically in an aqueous medium. The crystallinity and chemical bonds were studied by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). FTIR spectra before calcination showed the characteristic bonds of In–OH and Sn–OH at 1160 cm-1 and 1380 cm-1, respectively. After calcination at 400°C for 2 h, these characteristic bonds disappeared, confirming the formation of crystalline oxide. Moreover, scanning electron micrographs revealed well-defined structure, called nanorice, emerging from controlled crystal growth at 85°C for 90 min. The particle size of ITO was approximately 500 nm in length and diameter of 150 nm. The effect of crystallinity was studied by UV absorbance and NIR reflectance. These demonstrated promising results for use as energy-saving windows.