Synthesis and characterization of integrated SWCNT-Pt-P2O5-based sensor platforms for absolute humidity measurement

In this work we report synthesis and characterization of integrated SWCNT-Pt-P2O5-based sensors for absolute humidity (AH) measurement. The sensors were obtained by direct deposition of an active doped layer to the surface of an interdigitated planar sensor type, by drop cast method. For the experimental investigation two sensors with the same active layer were fabricated and tested for detecting water humidity in inert gas at room temperature. The sensing mechanism of the fabricated sensors is characterized by the electrical variations in sensors resistance, as a function of the AH related to the water trapping effect produced at the surface of the active layer. This physical behavior confirms the existence of a resistive path formed between the structured microelectrodes. The resistivity of the layer increases or decreases proportional to the raise or decline of the AH values in the range of 1% to 90% for the tested gas, as a result of an electrolysis process that takes place under sensors supply voltage, influenced also by the Pt catalyst. The sensors, so fabricated, exhibit remarkable sensing, stability and recovery capabilities and could be integrated in an efficient low-powered sensor-platforms for industrial usage.