Functionalization of graphene layers and advancements in device applications

The invention of graphene, as a two-dimensional (2D) atomic layered material, has created enormous scientific revolutions in materials science. As a result, there are a variety of 2D materials came into limelight and intervening the existing technology. Today, one of the focusing issues in graphene technology is the development of functionalized (doped) graphene monolayers since the pristine graphene is chemically inert, hydrophobic and zero band gap material. As a result, the potential applications of graphene are limited to a few fields of science and technology. Surface functionalization, one of the typical approaches, is well-adopted for the development of functionalized graphene layers. In this scenario, we reviewed the latest advancements exclusively in the development of functionalized graphene layers, and exciting breakthroughs in graphene's science and technology. A brief history along with intrinsic properties of graphene is discussed in the introduction. Then, the methods adopted for the realization of functionalized graphene layers, and the impact of surface modification on their physical and chemical properties along with device performances are elaborately discussed. Finally, the review is summarized and outlined the perspectives of functionalized graphene layers in view of the development of multifunctional high-quality graphene layers for next-generation device applications.