Characteristics of Printed Thin Films Using Indium Tin Oxide (ITO) Ink

Abstract

Characteristics of the indium tin oxide (ITO) thin films fabricated by a direct printing method were investigated. For the direct printing, 30 mass% ITO ink was formulated by dispersing ITO nanoparticles of less than 10 nm in diameter into alcohol based solvent with additives. Then, the ITO ink was printed onto a glass substrate, which was followed by the heat treatment at 350, 400, 500 and 600°C to fabricate the sintered films. Then, cross-section of sintered film was observed. As a result, the ITO thin film showed porous nanostructure. Also, sheet resistance of the ITO thin film decreased with increasing heating temperature. The decrease of the resistance was attributed to the improvement of carrier concentration in the ITO thin film. In the meanwhile, the optical transmittance increased in proportional to the heating temperature. In case of the ITO thin film heated at 600°C, the improved characteristics of the electrical resistance and the optical transmittance were achieved as 2.19×103 Ω/sq and 78.6%, respectively.