Adsorption Properties Of Organic Small Molecule On Doped Graphene:A First-principle Study

As a novel member of carbon structures,graphene has attracted intense attention since its first discovery in experiments by physicist Andre Geim and Konstantin Novoselov in 2004.Due to its unique geometric construction and physical and chemical properties,such as excellent electric conductivity,high specific surface area,high mechanical strength,graphene has became an important new material with numerous potential applications.Based on its intrinsic properties,graphene has been widely applied in various aspects,such as solar cell technology,nanoelectronic devices,gas sensors,gene electronic sequencing technology,field-effect transistors,and spintronic devices.Graphene-based nanomaterials are widely used in various types of sensing devices,not only for its excellent two-dimensional structure can maximize the interaction between the film surface and the adsorbate,but also cause significant changes of its conductivity.In addition,in order to improve the sensitivity of graphene to the adsorbed molecules and other electronic structures,the methods of graphene substrate defects and dopants are also widely used in experimental and theoretical studies.At the same time,due to its high potentiality for spin-polarized transport based on the unusual properties such as the small spin-orbit coupling and hyperfine coupling,as well as the excellent charge carrier mobility,graphene has been widely used in spintronic devices.In this paper,the calculations are performed within first-principle method based on density functional theory?DFT?using the vienna ab-initio simulation package?VASP?.The adsorption properties of CHCl₃ adsorbed on graphene or doped graphene and the spin polarization properties of benzene/graphene doped with transition metals are also studied.The conclusions are as follows:?1?The adsorption properties of chloroform molecule?CHCl₃?on the surface of graphene are studied experimentally and theoretically.The conductivity of the system will increase with the increasing of the adsorption distances.The density of states,the adsorption energy and the effective masses are also calculated and the analyses are consistent with the experimental conductivity properties.Graphene adsorbed with different molecule would induce different electronic structure and the conductivity would different.?2?Electronic structures of CHCl₃ adsorbed on N-doped and Al-doped graphene are studied.When CHCl₃ is adsorbed on N doped graphene,it is found that the structures of the system have no obvious change comparing with the case when CHCl₃ is adsorbed on pristine graphene,the adsorptions of CHCl₃ on pristine graphene and N-doped graphene are physical adsorption.The electronic structure of the system would change significantly when CHCl₃ is adsorbed on Al-doped graphene.The interaction between CHCl₃ and Al-doped graphene is strong,and Al-doped graphene could act as sensor to detect CHCl₃.?3?We also have performed a theoretical study on the spin polarization properties of benzene molecule adsorbed at the graphene surface,which doped with transition metals including Mn,Cr,Fe,Co,Ni.According to the PDOS,we found that the benzene molecule become spin polarized after being adsorbed at Mn-and Cr-doped graphene.The spin-polarized density distributions as well as the differential charge density distributions of the systems are obtained.The bigger charge transfer and bigger adsorption energy as well as the shorter adsorption length of benzene molecule adsorbed at Mn-doped graphene suggest that the greater spin polarization will be obtained in this case.