Fabrication of a Handheld Gadget for Breath Alcohol Detection Based on CuO-Decorated Fe2O3 Nanoflakes

In this paper, a handheld gadget for breath alcohol detection was developed. The proposed device was based on CuO-decorated Fe ₂ O ₃ nanoflakes (NFs). A miniaturized platinum micro-heater was integrated on sensor substrate, already equipped with the interdigitated electrodes (IDEs). The heater was calibrated by applying different voltages to provide the desired temperatures. For decoration of CuO nanoparticles (NPs) on Fe ₂ O ₃ NFs, different thicknesses of Cu thin films were deposited on the Fe ₂ O ₃ NFs using DC magnetron sputtering and by subsequent annealing, CuO as isolated NPs were decorated on Fe ₂ O ₃ NFs. The sensing results showed that the decoration of CuO NPs led to an improvement in the sensing properties of the gas sensor. The gas sensor can be powered by foldable solar panels or mains electricity. The proposed gas sensor was able to wirelessly send the sensing results to the smartphone where operator could monitor the changes in the gas sensor response in real-time. Optimal gas sensor showed a response of 10 to 100 ppm ethanol at 250°C and the response and recovery times were 12 and 57 s, respectively. Hence, relatively fast response time, high response, good repeatability, and selectivity of optimal gas sensor make it a suitable candidate for alcohol sensing applications.