Flexible Ethanol Sensor Based on ZnO-Based Nanomaterials Prepared by Hydrothermal Method

Abstract

Metal oxide semiconductor ethanol sensor is widely used in alcohol driving detection, biomedical and industrial fields. As a typical n-type semiconductor, ZnO has a certain response to ethanol at a certain temperature, but there is still a large room for improvement in gas sensing characteristics such as sensitivity, response and recovery time, selectivity and so on. In this paper, the orthogonal experiment is used to design the experiment. Taking the hydrothermal reaction time, hydrothermal reaction temperature and the molar ratio of zinc oxide to thiourea as the three important variables in the orthogonal experiment, nine groups of representative ZnO-ZnS powder samples with different process combinations are prepared by hydrothermal method. The structure and morphology of the nine samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectrometer (EDS). The optimal preparation scheme of ZnO-ZnS is selected, and the sensor based on polyimide is integrated. The gas sensing characteristics of ZnO-ZnS and pure ZnO sensors are tested by static gas distribution method. The results show that ZnO-ZnS nano materials have good sensitivity to ethanol, and the sensitivity to 100 ppm ethanol gas is 67.35 at 300 °C, and the response and recovery time is about 15 seconds. The prepared flexible sensor also shows good selectivity and stability, which provides a reference for the preparation of high-performance flexible ethanol sensor in the future test.