English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The electronic properties of graphene nano-flakes (GNFs) with different edgepassivation is investigated by using density functional theory. Passivationwith F and H atoms are considered: C$_{N_c}$ X$_{N_x}$ (X=F or H). We studiedGNFs with $10<N_c<56$ and limit ourselves to the lowest energy configurations.We found that: i) the energy difference $\Delta$ between the highest occupiedmolecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO)decreases with $N_c$, ii) topological defects (pentagon and heptagon) break thesymmetry of the GNFs and enhance the electric polarization, iii) the mutualinteraction of bilayer GNFs can be understood by dipole-dipole interactionwhich were found sensitive to the relative orientation of the GNFs, iv) thepermanent dipoles depend on the edge terminated atom, while the energy gap isindependent of it, and v) the presence of heptagon and pentagon defects in theGNFs results in the largest difference between the energy of the spin-up andspin-down electrons which is larger for the H-passivated GNFs as compared toF-passivated GNFs. Our study shows clearly the effect of geometry, size,termination and bilayer on the electronic properties of small GNFs.This studyreveals important features of graphene nano-flakes which can be detected usingRaman spectroscopy.

Electronic properties of graphene nano-flakes: Energy gap, permanent dipole, termination effect and Raman spectroscopy