Charge carrier transport across grain boundaries in graphene

Abstract

We evaluate the charge carrier transmission across asymmetric grain boundaries (GB) in a graphene lattice within the Landauer-Büttiker formalism. We employ a tight-binding model for C-based materials that accounts for lattice strain introduced by topological defects, such as grain boundaries. In particular, we investigate electronic transmission across grain boundaries found to be stable up to high temperatures. Our calculations suggest that the introduction of GBs generally preserves the zero-transport gap property of pristine graphene. However, only some specific asymmetric GBs open a moderate transport gap, which can be as high as ≈ 1.15 eV . We find that the GBs that introduce a transport gap are characterized by the existence of a mismatch along the GB. Indeed, the magnitude of this mismatch appears to be the main structural variable that determines the transport gap size, with greater mismatch resulting in larger transport gaps. Finally, we find that the presence of GBs reduces considerably electron transmission, and less so hole transmission.

Polystyrene-Based Triboelectric Nanogenerators for Self-Powered Multifunctional Human Activity Monitoring

“…Another factor increasing the triboelectric response in the PS-TENG made with 40 mg/mL PS solution is its higher amorphous nature in comparison to other films with higher concentrations, as reported earlier in many studies. − The higher amorphous content may promote deep charge trapping in polymeric insulators with aromatic rings in their monomeric structures. − Because of the inherent electrical resistivity of polymer films, charges remain largely trapped, which can increase the charge storage capacity of the polymer material. In addition, not only the charge generation but also the surface charge distribution is improved in amorphous films in comparison to crystalline films as a result of lesser grain boundaries, , which may further support higher surface charge density. The transferred charges have been calculated from the integration of the current signal over time (Figure S1).…”

“…55−59 Because of the inherent electrical resistivity of polymer films, charges remain largely trapped, which can increase the charge storage capacity of the polymer material. In addition, not only the charge generation but also the surface charge distribution is improved in amorphous films in comparison to crystalline films as a result of lesser grain boundaries, 60,61 which may further support higher surface charge density. The transferred charges have been calculated from the integration of the current signal over time (Figure S1).…”

Steric Interference in Bilayer Graphene with Point Dislocations

“…Fully coupled thermomechanical-electronic structure calculations of defects in monolayer graphene, including grain boundaries, have been presented in previous work [19]. As noted by numerous authors, the presence of lattice defects profoundly influences the electronic transport properties of graphene, including its band gap structure.…”

“…Xiao et al [16] studied the deterioration of the mechanical properties of graphene due to the presence of this type of defects by using an atomistic based finite bond element model. It is found that the Stone-Wales defect modifies the chemical [17] and electronic [18,19] properties of pristine graphene lattices. 7-5 pair structures can also combine to form dislocation dipoles [20].…”

Pell-Shear-Exfoliation of few-layer graphene nanoflakes as an electrode in supercapacitors

“…Because of the high surface to volume ratio of carbon materials causing relatively high specific charge storage, they can be used as an electrode in the energy storage devices such as Supercapacitors. Ideally, a monolayer of sp 2 bonded carbon atoms can reach specific capacitance up to ~550 F/g, large sur-face area of 2675 m 2 /g, high intrinsic mobility of 200,000 cm 2/ (V.s), and optical transmittance around 97.7% (6,(21)(22)(23)(24)(25) , which basically set the upper limit for all carbon materials. Therefore, an extensive attention is given to utilizing graphene in the supercapacitor device (2,(26)(27)(28)(29)(30)(31)(32).…”