NO 2 gas sensing performance enhancement based on reduced graphene oxide decorated V 2 O 5 thin films.

Here, we demonstrate improved NO ₂ gas sensing properties based on reduced graphene oxide (rGO) decorated V ₂ O ₅ thin film. Excluding the DC sputtering grown V ₂ O ₅ thin film, rGO was spread over V ₂ O ₅ 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 V ₂ O ₅ thin film due to the p-type and n-type nature of rGO and V ₂ O ₅ , respectively. Initially with rGO decoration on V ₂ O ₅ thin film, current decreased in comparison to the pristine V ₂ O ₅ thin film, whereas depositing rGO film on a glass substrate drastically increased current. Among all sensors, only the rGO-decorated V ₂ O ₅ sensor revealed a maximum NO ₂ gas sensing response for 100 ppm at 150 °C, and it achieved an approximately 61% higher response than the V ₂ O ₅ 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 V ₂ O ₅ . 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 V ₂ O ₅ thin film are highly suitable for the purpose of NO ₂ gas sensing. They enable the timely detection of the gas, further protecting the ecosystem from its harmful effects.