Na-Doped ZnO and RGO Composite-Based Flexible Acetone Gas Sensor Operated in Room Temperature

Real-time health monitoring is important in disease prediction, prevention, and early treatment. In this study, based on Na-doped ZnO/reduced graphene oxide (RGO) heterojunction, an ultrasensitive flexible room temperature gas sensor was developed for lung cancer surveillance diagnosis. The sensing material was synthesized using a simple solution route. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy were carried out to investigate the structure and chemical properties. The fabricated material has a surface-to-volume ratio, which was important to the sensing property. The gas-sensing performance was measured from 5 ppm to 200 ppm at room temperature (25 °). The proposed sensor demonstrated fast response and recovery time, as well as great repeatability and long-term stability. Furthermore, it exhibited mechanical robustness, and can be bent to different angles with almost no resistance change. Moreover, performance investigation at low acetone concentrations (0.2 ppm to 1.0 ppm) revealed its capability of distinguishing acetone gas as low as 0.2 ppm, with good linearity under different acetone concentration. As such, the developed sensor could provide a promising basis for disease monitoring through detecting the concentration of acetone gas exhaled by human.