Quaternary Oxidized Carbon Nanohorns -Based Nanohybrid as Sensing Layer for Room Temperature Resistive Ethanol Sensing

We report the ethanol sensing response of a resistive sensor employing a sensing layer based on a quaternary nanohybrid comprising oxidized carbon nanohorns, graphene oxide, SnO 2 , and polyvinylpyrrolidone, at 1/1/1/1 w/w/w/w mass ratio. The sensing device includes a flexible polyimide substrate and interdigital transducer-like electrodes. The sensing film is deposited via the drop-casting method on the sensing structure. The sensing layer morphology and composition are investigated through Scanning Electron Microscopy and Raman spectroscopy. The developed chemoresistive structure shows good sensitivity to concentrations of alcohol vapors varying in the range of 0.008 – 0.177 mg/cm ³ . The resistance of the proposed sensing structure increases over almost the entire range of measured ethanol concentration, with a maximum at an alcohol vapor concentration of 0.16 mg/cm ³ . The ethanol sensitivity of the proposed sensing layer is thoroughly explained by 2 theories, including the Hard-Soft Acid-Base principle.