Ethanol sensor has been widely used in our daily life and industrial production, such as drunk driving test, food fermentation monitoring, and industrial gas leakage monitoring. With the advent of the Internet of Things (IoT) era, ethanol sensors will develop towards miniaturization and low-power consumption in the near future. However, traditional ethanol sensors with large volumes and high-power consumption are difficult to meet these requirements. Therefore, it is urgent to study ethanol gas sensors based on new materials and new structures. Here, we demonstrated a flexible ethanol sensor based on an ion gel-coated graphene field-effect transistor (IGFET). The device has a small graphene channel size with a width of 300 μm and a length of 200 μm. The device showed a low operating voltage of less than |±1| V. When the device was put into an ethanol gas condition, the Dirac point voltage of the IGFET showed a negative shift, which means an n-type doping effect to the graphene channel. Furthermore, the sensor showed a normalized current change of-11% against an ethanol gas concentration of 78.51 g/L at a constant drain-source voltage of 0.1 V. In addition, the device exhibited a fast response time of ~10 s and a recovery time of ~18 s. Moreover, the detectable range of the device was found to as wide as 19.76-785.1 g/L. Based on the above results, the flexible IGFET-based ethanol sensor with small size and low-power consumption has great potential to be used in the industrial production of the IoT era.
A highly sensitive piezoresistive sensor based on MXenes and polyvinyl butyral with a wide detection limit and low power consumption
