Ultrasensitive and stable all graphene field‐effect transistor‐based Hg2+ sensor constructed by using different covalently bonded RGO films assembled by different conjugate linking molecules

Abstract As "molecular bridge," coupling agents can not only realize the covalent connection of composites, but also affect their properties, thus affecting the properties of devices based on them. Herein, leveraging differences in charge conduction properties of the (3‐aminopropyl)trimethoxysilane and 5,10,15,20‐tetrakis(4‐aminophenyl)‐21H,23H‐porphine caused by conjugacy structural differences, two kinds of layer‐by‐layer assembled smart carbon materials with different electrical properties are obtained at the same reduction temperature. The two graphene ultrathin films are then “planted” on Si/SiO2 substrates, respectively, as semiconductor layer and source/drain electrodes to fabricate an ultra‐stable all‐graphene field effect transistor (AG‐FET). Enabled by the covalent functionalized configuration and the functionally diverse of coupling agents, the AG‐FET obtained by this simple method won the high electrical characteristics, the hole, electron mobility, and the shelflife could reach 3.79 cm2/(V·s), 3.78 cm2/(V·s), and 18 months, respectively. In addition, good material stability and excellent device structure endow the device exceptional stability, electrical stability, and solvent resistance, improving its application prospect in solution phase sensing/detection. Such characteristics could be used to sense, transduce, and respond to external stimuli, especially in solution phase to monitor the important analytes, such as Hg2+ in a flowing sewage environment. We believe that such easy‐to‐manufacture AG‐FETs with ultrahigh performance and ultrahigh stability could also show great application prospects in other significant fields.