Formation of indium tin oxide film by wet process using laser sintering

• Indium tin oxide (ITO) films were prepared via laser processing with a continuous wave (CW) laser using an In–Sn alloy nanoparticle ink based on a wet process.
• Compared with other wet process using ITO nanoparticle, the laser process was simplified and the optical and electrical properties of the ITO film were improved.
• The micropatterning of the ITO film was studied by applying the laser direct writing to an In–Sn alloy nanoparticle film.
• The ITO micro-pattern with an accurate linear and sharp edge profile could be obtained by laser direct writing without photolithography processes.

Indium tin oxide (ITO) films were prepared via a very simple and low-cost preparation technique based on a wet process using a continuous wave (CW) laser and an indium tin (In–Sn) alloy nanoparticle ink. The formation of continuous transparent conductive films using a laser sintering method and micropatterning of the ITO films using a laser direct writing method were investigated. This process is simpler than the conventional two-step heat treatment method and other wet processes that use ITO nanoparticles as starting materials. In addition, the optical and electrical properties of the ITO films were improved. Notably, the conductivity and transmittance were remarkably influenced by the processing parameters, including the laser power and scan speed. Suitable processing conditions were thus investigated and optimized, and ITO micropatterns with accurate linear and sharp edge profiles were obtained by controlling the laser power and focusing conditions in the laser direct writing process.