Investigation of TiO Thick Films as Sensing Layers in Conductimetric pH Sensors

Abstract

Due to the demand for accurate, reliable and highly sensitive pH sensors, research is being pursued to find new materials to achieve this goal. An important branch of materials to be investigated for this purpose are the semiconducting metal oxides. This work uses titanium monoxide thick films in conjunction with an interdigitated electrode pattern to produce a conductimetric pH sensor. Its advantages over other methods include simpler construction and it is more economical. It was noted that upon contact with a solution, the resistance of the film increases. No meaningful relationship was observed between the resistance and pH for these devices. When a DC bias is applied to the device, a linear decrease was recorded in the relative changes in current through the device and conductance of the film against increasing pH values. Low frequency AC signals also produce a similar response. However, a slow response time and poor repeatability were also observed.