Effects of the Concentration of Indium-tin-oxide (ITO) Ink on the Characteristics of Directly-printed ITO Thin Films

Indium tin oxide (ITO) is widely used in nearly all types of display technologies due to its superior physical properties, such as environmental stability, relatively low electrical resistivity and high transparency to visible light. Here, fine ITO nanoparticles were successfully manufactured by applying a low-temperature synthesis method. Then, we formulated ITO inks containing 10, 20, and 30 wt% of ITO nanoparticles for inkjet printing to investigate the effects of ITO concentration on the electrical and the optical characteristics of the printed film. As a result, the ITO nanoparticles heated at 300 degrees C showed peak characteristics of an ITO structure with good crystallinity without any impurity phase. The electrical conductivity of the ITO film increased while the optical transmittance decreased with increasing ITO concentration in the ink.