Room temperature ethanol sensor based on ZnO nanoparticles modified by WSe2 nanosheets

Ethanol gas sensors have been widely applied in food safety, biomedicine, and fuel processing. However, most ethanol sensors need to be operated at high temperature. The development of room temperature ethanol sensors with low cost and high sensitivity is still a challenge. Here, a low-cost room temperature ethanol gas sensor is realized by connecting interdigital electrodes (IDEs) coated with ZnO/WSe2 nanocomposite film in series with a quartz crystal resonator (QCR). The change in ethanol gas concentration can be converted into a frequency shift of the quartz resonator to generate a quasi-digital signal through the sensor. Compared with pure ZnO IDEs-SQCR sensor, the sensitivity of ZnO/WSe2 IDEs-SQCR sensor (4.87 Hz/ppm) has been significantly improved in ethanol concentration range of 0-400 ppm. This is mainly attributed to the introduction of WSe2 with good conductivity, which not only enables the composite to have a special layered three-dimensional structure conducive to the adsorption and diffusion of gas molecules, but also puts the resistance of the composite in a more sensitive tuning range. The proposed sensor can be fabricated on a printed circuit board (PCB) so as to reduce the cost of mass production.