Graphene quantum dots with Stone-Wales defect as a topologically tunable platform for visible-light harvesting

TL;DR

This study demonstrates how Stone-Wales defects in graphene quantum dots can be used to tune their optical properties, especially enhancing visible-light absorption for applications in light harvesting and optoelectronics.

Contribution

It is the first to show the impact of topological Stone-Wales defects on the optical tuning of graphene quantum dots using first-principles calculations.

Findings

SW defects alter optical absorption spectra and introduce new defect-induced peaks.

Electron correlation effects are more significant in SW-defected GQDs.

SW defects at specific locations enhance visible-light absorption.

Abstract

In this work, we report for the first time the crucial role of topological anomalies like Stone-Wales (SW) type bond rotations in tuning the optical properties of graphene quantum dots (GQDs). By means of first-principles calculations, we first show that the structural stability of GQDs strongly depends on position of SW defects. Optical absorption spectra is then computed using electron-correlated methodology to demonstrate that SW type reconstruction is responsible for the appearance of new defect-induced peaks below the optical gap and dramatically modifies the optical absorption profile. In addition, our investigations signify that electron correlation effects become more dominant for SW-defected GQDs. We finally establish that the introduction of SW defects at specific locations strongly enhances light absorption in visible range, which is of prime importance for designing light harvesting, photocatalytic and optoelectronic devices.