Roya Maboudian (Advisor)

Despite decades of study and deployment, chemiresistive gas sensors based on SnO2 suffer from baseline drift due to aging of the SnO2 sensing material. In this work, we investigate how repeated, simulated operation of SnO2-based sensors causes irreversible changes in the electronic sensing behavior of SnO2, quantified through the bulk and inter-grain resistance of SnO2 as measured by potentiometric impedance spectroscopy (PIS). In tandem, we apply powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to link the observed changes in the bulk and inter-grain...

With the rise of interest in the Internet of Things (IoT), the need for low-power sensors for monitoring the working environment has been in spotlight. Considering the number of sensors required to provide real time monitoring, creating sustainable and self-powered sensors is essential. Triboelectric nanogenerator (TENG), which converts mechanical motion to electrical energy, is one of the most promising candidates for realizing self-powered sensors due to its sensitivity to surface material properties and ability to generate consistent signals depending on mechanical input. Here, we...

SnO2-based chemiresistive gas sensors can effectively detect combustible, explosive and toxic gases, and have been widely used in safety monitoring and process control in residential buildings, in various industrial settings and in mines. However, sensitivity and selectivity are still needed to be further improved for most current SnO2-based gas sensors. In addition, their high power consumption due to their high working temperature (200-400°C) limits their further development. Graphene, due to its unique characteristics (such as excellent electrical conductivity, large surface...

In this study, we report on the synthesis of the NiO/ZnO heterostructured nanowires by a facile two-step liquid phase route and their gas sensing characteristics employing Au interdigitated electrodes integrated on a miniature ceramic heater. Microstructural characterizations indicate that flocculent NiO particles are uniformly assembled on the outer surfaces of the single-crystalline ZnO nanowires, with diameters around 50 nm and lengths ranging from 500 nm to several μm. The gas sensing investigation indicates that the sensors based on NiO/ZnO heterostructured nanowires exhibit high...