Sub-ppm level detection of trimethylamine using V2O3-Cu2O mixed oxide thin films

Abstract

The present work deals in developing mixed compounds of vanadium sesquioxide (V2O3) and cuprous oxide (Cu2O) thin films using direct current (dc) magnetron co-sputtering technique for the detection of trimethylamine (TMA) vapour at ambient temperature (∼30 °C). The X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) characterizations confirmed the amorphous nature of V2O3-Cu2O thin film. The chemical stoichiometry of the mixed oxide film was determined as V+3 and Cu+1 oxidation states using X-ray photoelectron spectroscopy (XPS) analysis. The nanograin like morphology with an average particle size and thickness of about ∼15 and ∼85 nm was observed from field-emission scanning electron microscopy (FE-SEM). The TMA sensing studies proved that the sensor can detect a minimum of 3 ppm concentration with a sensor response (S = Ra/Rg) of ∼1.08. The developed sensor exhibited better sensitivity towards amine groups than alcohol, aldehyde, and ketone groups. Hence, it is believed that the developed Cu2O–V2O3 (VCO) mixed oxide can be a better amine sensor that can be utilized for the determination of fish quality.