Research Projects

The accelerated evolution of technologies for monitoring the safety of human health and detecting toxic gases and chemicals has introduced new challenges to gas sensors, which must ensure consistent and reliable performance under high humidity conditions. Conversely, addressing the trade-off between gas-sensing performance and its resistance towards humidity is challenging. In this route, the metal-decorated semiconductor-based chemoresistive gas sensors have been considered the most suitable owing to their simple structure, easy fabrication processes, and low cost. The fundamental approach to mitigate humidity cross-sensitivity of the semiconductor-based gas sensors is to prevent the formation of the hydroxyl groups on the sensing surfaces of the gas-sensing materials. The strategy of developing a gas-sensing device with different structures, which comprises one component with a strong water affinity and the other with high sensitivity to the target gas, has been proven to meet this requirement. Moreover, the gas sensor operating at elevated temperatures limits its widespread application, as it can lead to reduced sensor stability, increased risks associated with explosive or flammable gases, high energy consumption, and incompatibility with skin-patchable systems. In this context, activating the sensing surface by generating the photo-induced charge carriers can further improve the gas-sensing performances under light illumination rather than thermal activation of the sensor. Further, the increasing need for compact health monitoring systems necessitates advancements in sensor designs, especially in monitoring human health. In this project, we develop Au/Pt-based metal oxide (WO₃/TiO₂/In₂O₃) thin films with the deposition of a hydrophobic CeO2 thin layer to benefit from moisture and also the high light (UV/visible) absorption capacity of WO3, TiO2, and In2O3 thin films towards high-sensitivity even at room temperature. Herein, the simultaneous improvement in the gas-sensing performance and humidity-resistant properties of the chemoresistive gas sensors can be achieved by employing the Au/Pt-based metal oxide (WO₃/TiO₂/In₂O₃) thin films with a hydrophobic CeO₂ layer with a few nanometers thickness under light illumination to monitor lung cancer and type-1 diabetes, in addition to air quality and food safety.