Enhancing electrical and thermoelectrical performance of graphene nanoribbons through geometrical defect engineering

Graphene nanosheets are among the most promising materials for thermoelectric applications because of their exceptional electronic properties. However, their intrinsically high thermal conductivity significantly limits their thermoelectric efficiency. Defect engineering has emerged as an effective strategy for tailoring the electronic structure and transport characteristics of graphene by introducing localized states and suppressing phonon transport. In this study, the effects of different geometric modifications, including central drilling (center-to-edge), bidirectional drilling, and edge drilling (edge-to-center), as well as vertical structural modification, were investigated to enhance the thermoelectric performance of graphene nanosheets.

Density Functional Theory (DFT), combined with the Non-Equilibrium Green's Function (NEGF) formalism, was employed to investigate a series of graphene nanostructures positioned between two graphene electrodes (Figure 1). The electronic transport and thermoelectric properties of the defect-engineered graphene systems were systematically analyzed by calculating the quantum transmission characteristics and evaluating the influence of different drilling geometries and vertical multilayer configurations on their electronic structure and transport behavior.