Quantitatively Discriminating Alcohol Molecules by Thermally Modulating NiO-Based Sensor Arrays

Although temperature modulation of a single (nonselective) semiconductor gas sensor has demonstrated its great capability on discriminating gas molecules, quantitative analysis of the type and concentration of structurally similar volatile organic compounds (VOCs) molecules remains a significant challenge. In this work, as an alternative to a single oxide sensor, sensor arrays composed of four types of NiO-based sensor synchronously perform thermal modulation with a unique programmed cooling temperature profile. Apart from improved category discrimination by using entire sensor arrays, the peak temperature of the temperature profile plays an important role in distinguishing the concentration difference induced by subtle variations of the electrical responses. A high peak temperature of approximate to 300 degrees C facilitates concentration discrimination (with an accuracy ratio of 85.9%). This work highlights the importance of the peak temperature in (simultaneous) quantitative analysis of the types and concentrations of VOCs molecules with similar properties.

Automated summary

This study demonstrates that using a sensor array composed of NiO sensors for thermal modulation can improve the discrimination of different categories of gas molecules. The peak temperature of the temperature profile is crucial in distinguishing concentration differences induced by subtle variations in electrical responses.