Room temperature ethanol sensing by chemically reduced graphene oxide film

• Room temperature ethanol sensor developed using chemically reduced graphene oxide (rGO) film. • The rGO sensor exhibits response as high as 297 against 100 ppm of ethanol along with good repeatability. • The rGO sensor shows good selectivity to ethanol and its response remains unaffected by 50% relative humidity. Herein, we report the synthesis and fabrication of a low-cost sensor using thin film of chemically reduced graphene oxide (rGO) that can detect ethanol at room temperature with high sensitivity. X-ray Diffraction (XRD) confirmed the reduction of graphene oxide whereas high resolution electron microscopies and atomic force microscopy revealed existence of multiple (>20) layers within the rGO sheets. Optical band gap of rGO was estimated to be ∼ 1.7 eV from the UV–vis absorbance data whereas Raman spectrum confirmed the multilayered structure of rGO sheets. Thin films of rGO deposited on glass substrate showed sharp increase in current when exposed to ethanol vapor and exhibited response as high as 297 at room temperature against 100 ppm of ethanol. The rGO film sensor also showed fast response and recovery times of 2 s and 17 s, respectively and good repeatability over several cycles. The selectivity of the sensor to ethanol was also good as the response exhibited by it was much lower for other alcoholic vapors and almost nil to non-alcoholic VOCs and gases like CO and NO 2. Upon co-exposure to standard humid air of 50% relative humidity, the sensor response to ethanol did not change suggesting its suitability for practical applications.