Preparation Of The Graphene Devices And Analysis Of Their Property

Graphene，a two–dimensional monolayer of carbon atoms arrangedin a hexagonal lattice, has attracted unprecedented attention of scientistsdue to its unique excellent performance (e.g., highly active surface area,Johnson noise, etc.). The device modified by graphene films at roomtemperature shows a high carrier mobility, which endows them withbroad applications in the field of micro/nano–electronic technology, suchas electronics, energy storage, solar cells, display devices,chemical/biological sensor and the field effect tube sensor. Especially,since Novoselov reported the graphene field effect on Science for the firsttime, large–scale preparation of graphene and graphene based field–effecttube have attracted scientist’s keen interest. However, at present, theresearch of graphene based field–effect tube sensor has suffered greatchallenges in many fields such as construction of graphene devices,sensitive mechanism and application fields, which needed to be furtherexplored. For a specific target molecule, to design and select a suitablebiological or chemical molecules and chemical modification carries onthe graphene surface to form the sensitive layer with a molecularrecognition function are one of the important research content ofgraphene based field–effect sensor. The main research work of this paperincludes the following three aspects:1. Firstly, the interdigitated gold microelectrode (gold60nm,titanium10nm) with20μm gaps was fabricated using electron beamlithography on a Si wafer with1μm coating of SiO2; Secondly, grapheneoxide was prepared by modified Hummers method with natural flakegraphite as raw materials, and then the as–synthesized graphene oxidenanosheets were dispersed in deionized water by ultrasonic treatment for 12h to form a homogeneous dispersion. The as–synthesized grapheneoxide dispersion was injected on the electrode surface. we subsequentlyobtained the reduced graphene oxide (rGO) sensor throughelectrochemical reduction. Finally, we studied the performance of thesensor for selective detection of Hg2+in aqueous solution.2. We synthesized1–pyrenebutyl–amino–β–Cyclodextrin (PyCD)by using1–pyrenebutyric acid, ammonia and β–cyclodextrin, etc. as theraw materials. The pyrenyl group of1–pyrene butyric acid can stronglyinteract with graphene through π–π stacking to introduce the migration of1–pyrenebutyric acid molecules on the surface of rGO, and the carboxylgroups of1–pyrenebutyric acid can easily react with amine groups ofNH2-β-CD to form the PyCD compound, thus the constructing of a sensorwhich has a high sensitivity to picric acid was prepared successfully. Inaddition, we also discussed the performance of this kind of sensorresponding to other phenols such as p–cresol,2,4–xylenol,2–nitrophenol.Comparative results showed that the1–pyrenebutyl–amino–β–Cyclodextrin modified sensor has a highselectivity to picric acid.3. Using1–pyrenebutyric acid, anhydrous ethylenediamine andN,N’–dicyclohexylcarbodiimide (DCC), etc. as the starting materials tosynthesize1–pyrenebutyl–ethanediamine, and selectively modified on thesurface of reduced graphene oxide. This chemical modified sensor hasrealized the efficient detection of trinitrotoluene (TNT) in aqueoussolution. Compared with the naked reduced graphene oxide (rGO) sensor,we found that the1–pyrenebutyl–ethanediamine modified sensor hasmuch higher selectivity to TNT by the interaction of electronic group of1–butyrate pyrene–ethylenediamine and electrophilic groups of TNT.