Towards graphene based ultrasensitive chemical detectors: Lithium anchoring of organic molecules on the surface of graphene

Chemical sensing is one of the most promising applications of graphene based nanostructures. Here, we present a study of the effects of lithium adsorption on the electronic properties of graphene derivatives and its ability to serve as a chemical linker for different organic molecules. Lithium adsorption is found to significantly decrease the bandgap of armchair graphene nanoribbons (AGNRs), turning them metallic for sufficiently large adatom densities. However, upon the successive adsorption of an aromatic organic compounds at the lithium anchoring sites, all nanoribbons develop a bandgap. Therefore, in order to assess the performance of these systems as chemical detectors, we study their transport properties using a recently developed divide and conquer (D&C) approach. This enables us to evaluate the sensitivity of these systems toward relatively low adsorbate densities and suggests the possible implementation of GNRs as building blocks for chemical sensing devices.