Graphene nanoflakes - structural and electronic properties

TL;DR

This study investigates the structural and electronic properties of graphene nanoflakes using density functional tight-binding, revealing linear cohesive energy trends and complex HOMO-LUMO gap behaviors influenced by edge topology.

Contribution

It provides a comprehensive analysis of how size, topology, and edge saturation affect the stability and electronic properties of graphene nanoflakes.

Findings

Cohesive energy varies linearly with edge atom ratio.

HOMO-LUMO gaps depend on edge topology and size.

Edge unsaturation impacts stability and electronic structure.

Abstract

The structures, cohesive energies and HOMO-LUMO gaps of graphene nanoflakes and corresponding polycyclic aromatic hydrocarbons for a large variety of size and topology are investigated at the density functional based tight-binding level. Polyacene-like and honeycomb-like graphene nanoflakes were chosen as the topological limit structures. The influence of unsaturated edge atoms and dangling bonds on the stability is discussed. Our survey shows a linear trend for the cohesive energy as function of Ns/N (N - total number of atoms and Ns is number of edge atoms). For the HOMO-LUMO gap the trends are more complex and include also the topology of the edges.