Bimetals (Au-Pd, Au-Pt) loaded WO3 hybridized graphene oxide FET sensors for selective detection of acetone

Abstract

Efficient detection of acetone is important for a variety of applications in pharmaceutical, automotive industries, medical diagnosis etc. Surface modification is one of the potential method to enhance the sensitivity as well as selectivity of any sensors. In recent days, surface functionalization with bimetallic nanoparticles become attractive because of its enhanced catalytic properties and the possibility to form discrete heterojunctions. In this study, WO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> flowered morphology was prepared by one step acid precipitation method and bimetallic nanoparticles of Au-Pd and Au-Pt were deposited on WO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> /GO hybrid layer by one-step dip-coating process and fabricated a back gated field effect transistor (FET) structured sensor. Various morphological and structural characterizations were performed to study the various properties of the hybrid sensing layer. I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</inf> -V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</inf> characteristics and the acetone sensing performance were measured for both the sensors i.e., Au-Pd/WO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> /GO and Au-Pt/WO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> /GO at room temperature. Among the two sensors, Au-Pt/WO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> /GO FET sensor exhibited an appreciably high sensitivity of 56% towards 80 ppm acetone at room temperature under applied gate voltage (V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</inf> ) of 1.2V. The lower detection limit of the Au-Pt/WO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> /GO FET sensor was 400 ppb of acetone where it showed a 3 % response. The sensing mechanism envisages that the bimetallic loading in the ternary form of the nanocomposite enhanced sensitivity significantly by the spill-over effect. Also, the application of an optimized gate voltage amplified the sensitivity of the FET structured sensors.