Graphene has exceptional electronic,optical,mechanical and thermal properties which provide it with great potential for use in electronic,optoelectronic and sensing applications.However the gapless band structure greatly limits its wide applications in optoelectronic and photovoltaic devices.Surface functionalization proves to be an effective method to tune the properties of graphene.The chemical functionalization of graphene has been investigated with a view to controlling its electronic properties and interactions with other materials.In this study,hybrid graphene materials with enhanced properties were achieved through chemical doping of CVD grown graphene by introducing PTSA(n-type)and NBD(p-type)dopants.This type of doping is key building block for photovoltaic and optoelectronic devices.Doped graphene samples display(1)high transmittance in the visible and near-infrared spectrum and(2)tunable graphene sheet resistance and work function.　　Large area and uniform graphene films were produced by chemical vapor deposition on copper foils and transferred onto quartz as transparent substrates.For n doping,a solution of p-toluene sulfonic acid(PTSA)was first dropped and spin-coated on the10×10mm2graphene/quartz,and then annealed at100℃for10min to make graphene uniformly n-type.Subsequently,a10×10mm2bare graphene was transferred on another quartz,a solution of4-Nitrobenzene diazonium tetraflouroborate(NBD)was dropped and spin-coated on the surface of graphene,and similarly annealed.As a result,the graphene was p and n doped on the different quartz substrates.Doped graphene samples were characterized by different characterization techniques.Effect of reaction time on the functionalization of graphene was also studied.Experimental results suggested that doped graphene sheets with tunable electrical resistance and high optical transparency can be incorporated into photovoltaics and optoelectronics devices.