Improvement of electrical properties of printed ITO thin films by heat-treatment conditions

In this study, electrical properties of an indium tin oxide(ITO) thin film fabricated by inkjet printing were improved by optimizing the post heat-treatment conditions. For inkjet printing, 10, 20, and 30 wt% ITO inks were formulated, and they ITO inks were printed onto glass substrate. Then, the printed ITO thin films were heated at 300, 400, 500, and 600 °C under several atmospheric conditions of single step of N2, air and combination steps using the gases, respectively. As a result, the sheet resistance of the printed ITO thin film was decreased as the concentration of ITO ink and heat-treatment temperature were increased under single step of N2 atmosphere. In the case of the printed ITO thin film using 30 wt% ITO ink and heat-treatment at 600 °C under a N2 atmosphere, the improved sheet resistance and optical transmittance of 455 Ω/square and 90%, respectively, were achieved.