Design, Fabrication, and Packaging of an Optothermally Activated Nanocrystalline Pd–ZnO-Based Selective CO Sensor on a Screen-Printed In-Plane Heater Design, Fabrication, and Packaging of an Optothermally Activated Nanocrystalline Pd–ZnO-Based Selective CO Sensor on a Screen-Printed In-Plane Heater AITranslate

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DOI：https://doi.org/10.1021/acsaelm.1c01322

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Continuous monitoring of gases at low concentrations is necessary for keeping track of emanations from coal mines as gas emissions prove to be a detrimental factor for people working in such environments. Therefore, there is a requirement to develop a selective CO sensor which can go down to the ppm level for initiating the triggering of an alarm system. With this objective, a selective CO (up to 20 ppm) sensor has been investigated with the exploration of different material combinations (Pd–ZnO) and optothermal activation techniques. The selectivity of target gases such as CO, CH4, and NH3 has been a controversial topic among researchers as the sensing mechanism is almost similar in all the three cases. The major challenge to be addressed while designing a micro-electromechanical system-based gas sensor is the problem of reliability, cross-sensitivity, and selectivity, which stagnates the overall performance of the system. The optothermally activated sensor platform with suitable nanomaterials play a significant role in curtailing the above-mentioned issues. The present work implements Pd-doped nanocrystalline ZnO with defect-oriented active sites which are found to be highly efficacious in providing a sensor with a strong adsorption reaction and propelling the surface conversion kinetics. The sensor is optimized for selective CO sensing due to the interplay between the defect states on Pd–ZnO with optical and thermal activation. As a direct consequence, a reliable, robust, cost-effective, and CO-selective packaged gas sensor at approximately 3.5 W is realized. Simulation, optimization of the sensing nanomaterial, fabrication of a screen-printed integrated heater and sensing electrodes, thermo-optical excitation, detailed packaging, and characterization are discussed in this study. Thus, the present methodology to fabricate the CO-selective sensor is suitable for various applications where a robust, reliable, selective sensing performance is required. Detailed material characterization has been performed to analyze the sensing behavior of the grown nanomaterials (Pd–ZnO).