NO2 sensing properties of porous fibrous reticulated WO3 thin films

- Porous reticulated fibrous morphology of WO3 were synthesized via the simplistic chemical route.
- The nano-fibrous of WO3 exhibited excellent and highly selective gas response ∼5.75 for 5 ppm of NO2 gas.
- The synthesis route and sensing behavior of as synthesized WO3 revealed a promising candidate for fabricating low-consumption gas sensors.

In this work, the WO3 thin films were synthesized onto glass substrates at 673 K by simple and cost-effective spray pyrolysis technique for the NO2 gas sensing. Moreover, the WO3 thin film was synthesized as a function of different spray solution concentration. The structural and morphological results reveal the polycrystalline nature of WO3 thin films with pure monoclinic phase having porous fibrous reticulate morphology. The optical band gaps of WO3 thin films were observed ∼2.73 eV. Moreover, the activation energy in our WO3 sample (0.368 eV) is maximum than the theoretical value of activation energy (0.031 eV). Due to the outstanding morphology and grater activation energy, the WO3 thin films were used for NO2 gas sensing. The gas sensing properties of the thin film sensor based on WO3 thin films were studied in the range of 1-100 ppm of the NO2 at an operating temperature of 423 K (or 150 °C). The sensor exhibits better gas response around 5.75 for 5 ppm of NO2 gas as well as 84.75 for 100 ppm NO2 gas with better selectivity.