Fabrication of liquid sensor using ITO nano-powders

Abstract

We have investigated on the feasibility of printed Indium-Tin-Oxide sensor for the detection of hazardous and noxious substances (HNS) in the sea. To fabricate the thin film on a PET substrate, binder mixing ratio and heat treatment temperature were optimized in terms of the printing accuracy and electrical properties for printed layer. A porous thin film having a thickness of about 20 μm was prepared, and the heat treatment temperature of the thin film was determined from the viewpoint of deformation and deterioration of the PET substrate. Electrical measurements showed that the printed thin film has a resistivity of 1.58 Ω · cm and a carrier density of 1.4 × 1017 /cm3 and a mobility of 2.8 cm2/V·s. The operating characteristics of the sensor were confirmed by observing the resistance change by dropping a certain amount of sea water and ammonia (with verious concentration) on the surface of the layer, respectively. Also, the cause of resistance change by ammonia concentration was investigated from the point of view of change of ion concentration in electrolyte.