Nonlinear polarization effect of functionalized graphene quantum dots

TL;DR

This paper explores the nonlinear polarization properties of functionalized graphene quantum dots using semi-empirical calculations, revealing high optical nonlinearity and potential for second harmonic imaging applications.

Contribution

It provides the first semi-empirical analysis of the nonlinear polarization and hyperpolarizability of functionalized GQDs, highlighting their high nonlinear optical properties.

Findings

fGQDs exhibit high ta values indicating strong nonlinear optical properties

First hyperpolarizabilities correlate linearly with dipole moments

Potential application in second harmonic imaging microscopy

Abstract

Graphene quantum dots (GQDs) are nanoscale structures of graphene with quantum properties and edge effects that give photoluminescence properties. The effect of quantum confinement and differences in the nature of GQD structure makes its optical characteristics highly dependent on the size of the structure. This study explains a few exploratory semi empirical calculations of nonlinear polarization properties of functionalized GQD (fGQD) three dimensionally. Based on this, the calculation of the linear polarization and first hyperpolarization was performed by the finite field method, which is based on the expansion of the energy and dipole moment. As a result, the fGQD molecule dominantly has high optical nonlinear properties as indicated by the high \b{eta} values (71 to 4488 a.u.). In general, the first hyperpolarizabilities have a linear relationship with the dipole moments. It was potentially used for the second harmonic imaging microscopy (SHIM) application.