Electronic structure of oxygen-functionalized armchair graphene nanoribbons

TL;DR

This study uses first-principles DFT to explore how oxygen functionalization affects the electronic and magnetic properties of armchair graphene nanoribbons, revealing new magnetic states and tunable band gaps.

Contribution

It provides the first detailed analysis of oxygen passivation effects on AGNRs, including non-planar geometries and their impact on electronic and magnetic properties.

Findings

Oxygen passivation induces diverse geometries and magnetic states.

Non-planar structures are non-magnetic and semiconducting.

Quasiparticle corrections increase band gaps in all systems.

Abstract

The electronic and magnetic properties of varying width, oxygen-functionalized armchair graphene nanoribbons (AGNRs) are investigated using first-principles density functional theory (DFT). Our study shows that O-passivation results in a rich geometrical environment which in turn determines the electronic and magnetic properties of the AGNR. For planar systems a degenerate magnetic ground state, arising from emptying of O lone-pair electrons, is reported. DFT predicts ribbons with ferromagnetic coupling to be metallic whereas antiferromagnetically coupled ribbons present three band gap families: one metallic and two semiconducting. Unlike hydrogen functionalized AGNRs, the oxygen functionalized ribbons can attain a lower energy configuration by adopting a non-planar geometry. The non-planar structures are non-magnetic and show three semiconducting families of band gap behavior. Quasiparticle corrections to the DFT results predict a widening of the band gaps for all planar and non-planar, semiconducting systems. This suggests that oxygen functionalization could be used to manipulate the electronic structures of AGNRs.