Theoretical Study On The Properties And Defect Effects Of Functionalized Graphene

The unique mechanical,optical,magnetic and electronic properties of graphene have attracted extensive attention,and graphene become a hotspot in the research of two-dimensional materials.However,its gapless band structure and low chemical activity limit the application in semiconductor,catalysis and biomedical fields.To open the band gap and improve its chemical activity,functionalized graphene treats the surface with different functional groups to improve performance.As we all know,chemical corrosion in the functionalization process and possible high temperature or high pressure in the material growth process often lead to the generation of some defects,which have a great impact on its properties.In functionalized graphene,the defects may have complex interactions with the contained groups,which may be beneficial for us to further realize the precise control of graphene-like materials.In this paper,we investigated the vacancy defects of functionalized graphene.The effects of defects are analyzed by first-principles calculations.The main contents include:1.Three defects of fluorographene and single vacancy defect of graphene oxide were established.The results of structural optimization show that the defects distort the adjacent regions,resulting in changes in lattice constants.2.We carried out computational simulation of the interaction of vacancy defects in graphene oxide with different oxygen-containing groups.The stability of the defect structure was verified.Its electronic properties and magnetic sources were analyzed.Vacancy defects are found a red-shift in absorption spectrum.The defect destroys the perfect honeycomb structure of the graphene substrate,which makes the structure more sensitive to stress and realizes the regulation of the magnetic moment.3.The thermodynamic stability of defects in fluorographene was verified by molecular dynamics simulations.The results show that the defects change the band structure,introduce the defect energy level,and intensify the spin splitting,which lead to the appearance of localized magnetic moments.Due to the defects,the stress can have a significant effect on the spin splitting situation,which helps to realize the regulation of the band gap.