Thermal Transport in 3D Pillared CNT-Graphene Nanostructures

Abstract

Thermal transport in two types of 3D pillared SWCNT-graphene nanostructures, which combine graphene floors and (6,6) armchair single-walled carbon nanotube (SWCNT) columns is studied by measuring both in-plane and out-of-plane thermal conductivity using molecular dynamics (MD) simulations with the AIREBO interatomic potential. Interpillar distance and pillar height dependency of thermal conductivity in 3D pillared SWCNT-graphene super-structure are examined at various temperatures (300K, 600K, 900K, and 1200K). It is shown that the thermal conductivity of these 3D nanostructures can be readily tuned: the in-plane thermal conductivity increases with increasing interpillar distance while the out of plane thermal conductivity increases with increasing pillar height and decreasing interpillar distance. The highest in-plane thermal conductivity obtained is 40 W/m-K for 3D super-structure with Type 1 unit cell with a 3.3 nm interpillar distance and 1.2 nm pillar height at room temperature. The highest out of plane thermal conductivity is 6.8 W/m-K for 3D super-structure with Type 1 unit cell which has 2.1 nm interpillar distance and 4.2 nm pillar height. Later, these values are compared with the thermal conductivity values of pure (6,6) SWCNT and single graphene layer, which are calculated using MD with the same interatomic potential.