NO gas sensing performance enhancement based on reduced graphene oxide decorated VO thin films.

Here, we demonstrate improved NO gas sensing properties based on reduced graphene oxide (rGO) decorated VO thin film. Excluding the DC sputtering grown VO thin film, rGO was spread over VO thin film by the drop cast method. The formation of several p-n heterojunctions was greatly affected by the current-voltage relation of the rGO-decorated VO thin film due to the p-type and n-type nature of rGO and VO, respectively. Initially with rGO decoration on VO thin film, current decreased in comparison to the pristine VO thin film, whereas depositing rGO film on a glass substrate drastically increased current. Among all sensors, only the rGO-decorated VO sensor revealed a maximum NO gas sensing response for 100 ppm at 150 °C, and it achieved an approximately 61% higher response than the VO sensor. The elaborate mechanism for an extremely high sensing response is attributed to the formation and modulation of p-n heterojunctions at the interface of rGO and VO. In addition, the presence of active sites like oxygenous functional groups on the rGO surface enhanced the sensing response. On that account, sensors based on rGO-decorated VO thin film are highly suitable for the purpose of NO gas sensing. They enable the timely detection of the gas, further protecting the ecosystem from its harmful effects.