Synthesis and characterization of indium-tin-oxide particles prepared using sol–gel and solvothermal methods and their conductivities after fixation on polyethyleneterephthalate films

The focus of this study was on the physical properties of two types of indium-tin-oxide particles prepared via sol–gel and solvothermal methods. The In2O3 was shown to have a cubic structure from the X-ray diffraction patterns obtained after annealing of the particles prepared via the sol–gel and solvothermal methods at 1200 and 600 °C, respectively. The average particle size was measured using high-resolution transmission and scanning electron microscopies. The indium-tin-oxide particle sizes prepared using the solvothermal and sol–gel methods were within the ranges 10 to 30 nm and 30 to 50 nm, respectively. The surface charges of the sol–gel and solvothermally obtained annealed indium-tin-oxide particles in ethanol solution were + 28 and + 40, respectively, indicating that the latter were more stable. X-ray photon spectroscopy showed that the In ions in the solvothermally prepared indium-tin-oxide were more oxidized than those prepared using the sol–gel method. These indium-tin-oxide particles were fixed onto polyethylene terephthalate films using a silicon binder. The conductivity of the solvothermally prepared indium-tin-oxide/polyethylene terephthalate films was higher than that prepared by the sol–gel method: the resistance of the solvothermally prepared indium-tin-oxide (after annealing at 600 °C)/polyethylene terephthalate film was 2.0 × 104 Ω per square, but 5.0 × 104 Ω per square for that prepared via the sol–gel method.