Thermal properties of fluorinated graphene

TL;DR

This study uses atomistic simulations with a new reactive force field to analyze the thermal rippling and mechanical properties of fluorinated graphene, revealing its un-rippled nature and quantifying its Young's modulus.

Contribution

The paper introduces a new set of ReaxFF parameters optimized for fluorinated graphene and compares its thermomechanical properties with graphene, graphane, and BN.

Findings

Fluorinated graphene is un-rippled unlike graphene.

Young's modulus of FG is approximately 273 N/m (arm-chair) and 250 N/m (zig-zag).

FG exhibits distinct thermomechanical behavior compared to graphene.

Abstract

Large scale atomistic simulations using the reactive force field approach (ReaxFF) are implemented to investigate the thermomechanical properties of fluorinated graphene (FG). A new set of parameters for the reactive force field potential (ReaxFF) optimized to reproduce key quantum mechanical properties of relevant carbon-fluor cluster systems are presented. Molecular dynamics (MD) simulations are used to investigate the thermal rippling behavior of FG and its mechanical properties and compare them with graphene (GE), graphane (GA) and a sheet of BN. The mean square value of the height fluctuations $< h^2>$ and the height-height correlation function $H(q)$ for different system sizes and temperatures show that FG is an un-rippled system in contrast to the thermal rippling behavior of graphene (GE). The effective Young's modulus of a flake of fluorinated graphene is obtained to be 273 N/m and 250 N/m for a flake of FG under uniaxial strain along arm-chair and zig-zag direction, respectively.