Improvement of particle size of indium tin oxide nanoparticles by in situ dispersion method for solution based transparent heater
In this study, particles size of indium tin oxide nanoparticles (ITO NPs) was improved by in situ dispersion method. Polyvinylpyrrolidone (PVP) was used as dispersing agent, and reduced precipitates heat treated at 400 degC. Brunauer, Emmett Teller (BET) specific surface area (SSA) analysis and X ray diffractometer (XRD) observations found that their particle size was improved by using the in situ dispersion. In addition, we found that the particle size of the crystalline ITO NPs was changed with the concentration of the PVP as well as the heat treatment temperature. When 2 wt% PVP was applied, the highest BET SSA of the ITO NPs, 114.7 m2/g, was obtained after heat treatment at 400 degC. In fact, the lowest sized, less than 7 nm, ITO NPs was observed with high resolution transmission electron microscope (HRTEM) The ITO NPs were well dispersed in the solvent to formulate a 20 wt% ITO NPs solution. ITO NPs coated layer on 3 x 3 cm2 quartz substrate showed sheet resistance of 319 O/ and optical transmittance of 89.5% after heat treatment at 900 degC. Heat was well generated at the ITO NPs coated layer with supplied voltage. Also, temperature of above 150 degC was obtained from the transparent heater, and 89 degC was obtained with low power, 0.21 W/cm2, that is superior to commercial heaters.
Electronic Materials Letters