Bandgap evolution in nanographene assemblies

TL;DR

This paper investigates how the electronic bandgap in nanographene assemblies, specifically cycloarene structures, depends on molecular arrangement and bond density, using computational models to predict and interpret these effects.

Contribution

It introduces an effective model linking inter-molecular bond strength to the energy gap in particle-hole symmetric molecular assemblies.

Findings

Weak dependence of bandgap on assembly geometry

Strong dependence of bandgap on inter-molecule bond density

Effective model explains energy gap variations

Abstract

Recently cycloarene has been experimentally obtained in a self-assembled structure, forming graphene-like monoatomic layered systems. Here, we establish the bandgap engineering/prediction in cycloarene assemblies within a combination of density functional theory and tight-binding Hamiltonians. Our results show a weak dependence of the gap with the assembly geometry, contrasting a strong dependence with the inter-molecule bond density. We derived a effective model that allows the interpretation of the arising energy gap for general particle-hole symmetric molecular arranges based on inter-molecular bond strength.