Bridging interdigitated electrodes by electrochemical-assisted deposition of graphene oxide for constructing flexible gas sensor

Up to now, much effort has been paid in fabrication of graphene film on flexible substrate to meet various applications in energy, electronics, and sensors. However, commonly used method that transfer CVD grown graphene onto flexible substrate is still an uneconomic process. Herein, electrochemical-assisted deposition (ECAD) method was proposed to deposit graphene oxide (GO) on polyethylene terephthalate (PET) substrate patterned with interdigitated electrodes (IDEs). After in-situ reduction of GO film in hydrazine vapor, a homogeneous reduced graphene oxide (rGO) film bridging the IDEs on PET substrate can be obtained. Such rGO films displayed excellent electronic features and outstanding gas sensing performance. Baseline variation of the sensor constructed by ECAD is (similar to)0.003%, which is one tenth of that resulted from drop casting method. The limit of detection of the graphene sensor for isoprene and hydrothion are (similar to)237 ppb and (similar to)41 ppb (S/N > 3), respectively. To demonstrate its real application in food quality monitoring, odor emission in different fruit maturity stages was measured. The results demonstrated that the sensor can successfully trace the fruit maturity in realtime. We believe the ECAD method has great potential to prepare various types of flexible graphene devices.