Surface Defects of Electron Irradiation Engineering for Graphene/Polymer Composite-Based Flexible Humidity Sensors

A facile approach for surface defect engineering basedon high-energyelectron irradiation is proposed here to produce a graphene/polymercomposite flexible humidity sensor with high humidity resistance andresponsiveness. The responsiveness of the graphene/polymer compositehumidity sensor following electron irradiation was similar to 22.4-foldgreater than the unirradiated humidity sensor. When the relative humiditywas 97.3%, the responsiveness of the sensor was 1.2 x 10(5). In addition, the irradiated humidity sensor maintained anexcellent response after 10 water resistance tests. Furthermore, materialcharacterization techniques demonstrated that graphene/polymer compositematerials with low crosslinking density could be produced by electronirradiation at the appropriate fluence. Concurrently, the specificsurface area of the graphene/polymer composite material was increased,and several oxygen-containing functional groups were generated, providingmore active sites for water molecules to enhance the stability andresponsiveness of the sensor. Thus, the irradiated graphene/polymercomposite humidity sensor has potential applications in human respiratorymonitoring and noncontact switching. Moreover, the surface defectengineering of electron irradiation provides a facile strategy forobtaining graphene/polymer composite flexible humidity sensors withhigh comprehensive properties.