Effect of ordered mesoporous carbon contact layer on the sensing performance of sputtered RuO2 thin film pH sensor
School of Natural Sciences / Electron Science Research Institute
The effect of contact layer on the pH sensing performance of a sputtered RuO2 thin film pH sensor is investigated. The response of pH sensors employing RuO2 thin film electrodes on screen-printed Pt, carbon and ordered mesoporous carbon (OMC) contact layers are measured over a pH range from 4 to 10. Working electrodes with OMC contact layer are found to have Nernstian pH sensitivity (−58.4 mV/pH), low short-term drift rate (5.0 mV/h), low hysteresis values (1.13 mV) and fast reaction times (30 s), after only 1 h of conditioning. A pH sensor constructed with OMC carbon contact layer displays improved sensing performance compared to Pt and carbon-based counterparts, making this electrode more attractive for applications requiring highly-accurate pH sensing with reduced conditioning time.