Highly Sensitive and Selective Alcohol Sensors based on Ag-Doped In2O3 Coating

In this paper, we describe how to synthesize Ag-doped In 2 O 3 nano particles and fabricate highly sensitive and selective alcohol sensors by solid-state reaction treatment from In(NO 3 ) 3 ·5H 2 O and AgNO 3 mixtures at room temperature followed by calcination at 600 °C for 2 h. The samples were characterized by X-ray diffraction, scanning electronic microscopy, X-ray photoelectron spectroscopy. The diameter of the as-synthesized particle diameter is ∼80 nm under different dosage of Ag doping. In comparison with pure In 2 O 3 sensor, all of the Ag-doped sensors showed better sensing performance in sensitivity, selectivity and optimum operating temperature. The effects of Ag content, alcohol vapor concentration, and operating temperature on the sensing characteristics of the Ag-doped In 2 O 3 sensors were also investigated. We found that the Ag-doped sensor containing 10.0 mol % Ag exhibited the maximum sensitivity to alcohol vapor at 150 °C. A possible mechanism for the influence of Ag on the alcohol-sensing properties of Ag-doped In 2 O 3 sensors was proposed.