Enhanced humidity responsive ultrasonically nebulised V₂O₅ thin films

Abstract A large surface to volume ratio and easily accessible active reaction sites are key attributes for a good gas sensing material. Herein, we report synthesis, characterisation and humidity sensing properties of phase pure 420 nm thick low temperature (350 °C) polycrystalline V2O5 thin films deposited on quartz substrate by ultrasonic nebulized spray pyrolysis of aqueous combustion mixture (UNSPACM). The thin films were characterized by x-ray diffraction, Raman spectroscopy, atomic force microscope, field emission scanning microscope, transmission electron microscope, UV–visible spectroscopy and XPS. The highly porous and nanocrystalline characteristic of V2O5 thin films synthesized by this technique provide large surface to volume ratio and easily accessible active reaction sites making it a prominent material for gas sensing applications. The fabricated humidity sensor based on V2O5 thin films exhibited high sensitivity with good stability and reproducibility at room temperature. The sensor exhibited high sensitivity of 90.8% at 76% RH with response time of 35–60 s and recovery time of 7–54 s. We believe this method provides means for large-scale synthesis of V2O5 thin films for several gas sensing applications.