| Recently,two dimensional?2D?materials have attracted considerable attentions because of unique electronic structure,excellent physical and chemical properties.They also made high performance gas sensor possible thanks to their high surface-to-volume ratio and surface activity.However these sensing materials still exist some drawbacks,such as poor selectivity,low sensitivity.To improve these issues,new structure and materials developing is worthy of attentions.Here,we systematically demonstrate the novel structures for gas sensing,namely,graphene/PDMS composites and 2D heterostructure.The achievements of this work are as follows:1.Chemical gate gas sensor was realized based on 2D materials.And this 2D heterostructure used molybdenum disulfide?MoS2?as the channel materials,hexagonal boron nitride?h-BN?as the top-gate dielectric,and black phosphorus?BP?as the chemical gate material.The BP top-gate transistors have excellent performance with subthreshold slope close to 103 mV dec-1 and on/off ratio up to 107(Vds=1 V).And this heterostructure also exhibits high response of 8.21%when exposed the concentration of NO2 at 10 ppb and provide a detection limit of 53 ppt.The detection of volatile organic compounds?VOCs?also executed at room temperature.The results suggest that BP chemical gate sensor exhibits a high selectivity to DMF in comparison with other analytes.2.And we also present a chemiresistor gas sensor based on the graphene/PDMS nanocomposites.The graphene/PDMS nanocomposites is fabricated by mixing liquid exfoliated graphene nanosheets with PDMS in isopropanol.The conductivity of the nanocomposites is positive related with the graphene concentration,the percolation value of which is as low as 0.41 wt%.The detection limit of this sensor to hexane is calculated to be 200 ppb with decent repeatability,when the graphene concentration is0.45 wt%.The proposed gas sensor has great potential in industry applications due to its easy fabrication process,low cost and high sensitivity. |
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