Effect of temperature and humidity on the sensing performance of TiO2 nanowire-based ethanol vapor sensors

In this paper, we study the influence of two key factors, temperature, and humidity, on gas sensors based on titanium dioxide nanowires synthesized at 4 different temperatures and with different morphology. The samples' structure are investigated using SEM, XRD and FTIR analysis. The effects of humidity and temperature are studied by measuring the resistance and gas response when exposed to ethanol. At room temperature, we observed a 15% sensitivity response to 100 ppm of ethanol vapor and by increasing the operating temperature up to 180 degrees C, the response is enhanced by two orders of magnitude. The best operating temperature for the highest gas response is found to be around 180 degrees C. Also, it was observed that every nanowire morphology has its own optimum operating temperature. The resistance of sensors is increased at higher Relative Humidity (RH). Besides, the response to ethanol vapor experiences a gradual increase when the RH rises from 10% to 60%. On the other hand, from 60% to 90% RH the gas response decreases gradually due to different mechanisms of interaction of the TiO2 with H2O and ethanol molecules.

Automated summary

This study investigates the influence of temperature and humidity on gas sensors based on titanium dioxide nanowires, finding the optimal operating temperature to be around 180 degrees Celsius. Different nanowire morphologies have their own optimal operating temperatures. Additionally, the resistance of sensors increases at higher relative humidity, while the response to ethanol vapor gradually increases from 10% to 60% RH but decreases from 60% to 90% RH.