Fast, Highly Sensitive Interdigitated Capacitor Sensor to Detect Wide Range of Temperatures Using Graphene-Oxide-Containing Dielectric Membrane

Abstract

We proposed an interdigitated capacitor (IDC)-based temperature sensor that can measure temperatures from 0 °C to 120 °C. The principle of operation of the proposed sensor depends on the variation of the capacitance as the IDC sensor becomes warmer. Graphene oxide, a well-known conductive polymer, was mixed with polyvinylpyrrolidone polymer to prepare a temperature-sensitive dielectric sensing solution. This sensing solution was then deposited on the interdigitated electrode by a spin coater to prepare the IDC temperature sensor. The designed sensor has good sensing ability and offers stable sensing responses over a broad temperature range. The sensitivity and linearity (correlation coefficient R2) of the designed IDC temperature sensor were approximately 80.86 pF/°C and 0.998, respectively. The proposed sensor also has excellent reproducibility characteristics, with a relative standard deviation of approximately 0.024. We also proposed four IDC remote wireless temperature-sensing units to observe temperature variations in remote locations. The signal processing unit in both the local and remote wireless IDC sensing systems was designed to use a microcontroller. Finally, the response of the developed IDC temperature sensor was compared with those of temperature sensors, which were based on resistivity, the piezotronic effect, a graphene-assisted microfiber, optical fiber wavelength shifting, a Sagnac loop using a long grating optical fiber, and an optical fiber probe, in terms of the temperature measurement range and linearity. We found that the designed IDC temperature sensor exhibits excellent sensing performance compared with the other sensors.