Electronic Structures and Optical Properties of Partially and Fully Fluorinated Graphene

TL;DR

This study investigates how fluorination affects the electronic and optical properties of graphene, revealing the stability of paired fluorine atoms, the impact of various disorders on midgap states, and a method to distinguish fluorination effects via optical polarization.

Contribution

It combines ab initio G0W0 calculations with large-scale tight-binding simulations to analyze structural disorder effects and proposes a polarization-based method to identify fluorination mechanisms.

Findings

Paired fluorine atoms are more stable than unpaired ones.

Different disorders create distinct midgap states and optical excitations.

Polarization rotation measurements can distinguish fluorination-induced $sp^3$ bonds.

Abstract

In this letter we study the electronic structures and optical properties of partially and fully fluorinated graphene by a combination of abinitio G0W0 calculations and large-scale multi-orbital tight-binding simulations. We find that for partially fluorinated graphene, the appearance of paired fluorine atoms is more favorable than unpaired atoms. We also show that different types of structural disorder, such as carbon vacancies, fluorine vacancies, fluorine vacancy-clusters and fluorine armchair- and zigzag-clusters, will introduce different types of midgap states and extra excitations within the optical gap. Furthermore we argue that the local formation of $sp^3$ bonds upon fluorination can be distinguished from other disorder inducing mechanisms which do not destroy the $sp^2$ hybrid orbitals by measuring the polarization rotation of passing polarized light.