Thermal Conductivity of Graphene and Graphene Oxide Nanoplatelets

The superior thermal transport in graphene has been a topic of great interest to the scientific community, for graphene is envisioned to be important in numerous applications such as thermal management of electronics. While single layer graphene exhibits high thermal conductivity, molecular and lattice dynamics simulations reveal that even in the presence of one or few additional layers, thermal conductivity can be significantly reduced. In fact, with increasing number of layers, thermal conductivity is expected to eventually approach the value of bulk graphite. The interlayer spacing is also known to have a significant influence on thermal conductivity, for it is the combination of the number of layers and the spacing between them that truly is responsible for the thermal conductivity of a multi-layer graphene platelet. Here, we report the experimentally obtained thermal conductivities for nanoplatelets of graphene oxide and reduced graphene exfoliated to differing degrees. Results show that the thermal conductivity measured for reduced graphene platelets with 30 to 45 layers approaches the value of bulk graphite. The thermal conductivity of oxygen intercalated graphene nanoplatelets with similar to 3 layers and 7% oxygen is higher than bulk graphite with similar interlayer spacing. Despite the increased inter layer spacing and presence of the oxygen atoms, which typically enhances phonon scattering, the high value of thermal conductivity can be attributed to the increase in the interlayer coupling due to covalent interactions provided by the oxygen atoms.