Improved performance of graphene by effectively removing surface poly-methyl methacrylate residual during the process of wet-etching transfer

ABSTRACTUltraviolet (UV) treatment has been demonstrated to be an effective way to removing the poly-methyl methacrylate (PMMA) residual during the process of the wet-etching transfer of graphene. The UV/Ozone irradiation with appropriate time can effectively remove the PMMA residual, resulting in a performance improvement of graphene, including the surface morphology, carrier concentration, and sheet resistance. The work function of graphene could be tuned according to treatment time without loss to the transmittance of graphene. Furthermore, we have fabricated graphene-based OPVs with a power conversion efficiency of 3.33%, which increased by 18.7% compared to the OPV without graphene modification.