Thermal Transportation Behaviour Prediction of Defective Graphene Sheet at Various Temperature: A Molecular Dynamics Study

Abstract

Thermal transportation behavior and phonon-phonon scattering strongly depend on the temperature variation as well as percentage of defects in the pristine material. Non-equilibrium molecular dynamics (NEMD) simulation has been chosen as the pathway to investigate the effects of percentage of defects on phonon wave propagation and thermal transportation in single layer graphene sheet. From the simulation it is inferred that thermal conductivity of graphene sheet falls with the increase of % of defects. Optimized Tersoff potential has been employed to generate the decreasing trend of thermal conductivity of graphene sheet with the % of increase of defects. To investigate the effects of defect on the thermal conductivity, 0.2% (75 atoms), 0.5% (205 atoms), 1.05% (405 atoms), 1.32% (505 atoms), 3.13% (1200 atoms) atoms were deleted on the perpendicular of heat flow direction. To generate a more convenient outcome, Quantum correction has been applied below Debye temperature in order to include quantum effects for predicting thermal conductivity. This study concludes that up to Debye temperature, thermal conductivity shows an increasing trend with increasing temperature and then after it reaches a cliff, it starts to fall. Besides, as the percentage of defect increases, the thermal conductivity decreases. Thermal conductivity of graphene is so much high due to very strong sp2 bonding between C atoms but when there is defects, the C atoms do not find any atom to transmit heat and consequently thermal conductivity decreases.