Surface work function of chemically derived graphene: A first-principles study

•Surface work functions of graphene chemical derivatives are obtained.•Chemical decoration effectively modulates the surface work function of graphene.•Un-expected cases which do not follow the traditional rule are found.

Using first-principles calculations within the framework of density-functional theory, we systematically study the modulation effect of chemical decoration including hydrogenation, fluorination, and oxidization on the surface work function of graphene. The chemical decoration is effective approach to modulate the surface work function, which expands the space to design diverse nano-devices based on graphene. Moreover, we also find some un-expectation chemically decorated cases which do not follow the traditional rule of “electronegative (electropositive) adsorbates, which increase (decrease) the work function of the surface”. Such a phenomenon is mainly derived from the charge redistribution induced by the bonding process between adsorbates and carbon atoms along with the chemical decoration.