Monday, October 3, 2011

Heat at the Borders

Brown University School of Engineering professor Vivek Shenoy's work on thermal transport across grain boundaries in graphene (published in Nano Letters last month) has also been featured in the research highlights section of Nature Materials. An abstract of his paper, "Thermal transport across Twin Grain Boundaries in Polycrystalline Graphene from Nonequilibrium Molecular Dynamics Simulations" follows:

Heat at the borders

Fabio Pulizzi
Nature Materials
Published online
Nano Letters (2011)

Graphene exhibits the highest thermal conductivity ever observed. Its thermal transport has been studied theoretically and experimentally, mostly in single-crystalline graphene. Unfortunately, large-scale growth, for example by chemical vapour deposition (CVD), usually yields polycrystalline sheets. Akbar Bagri and colleagues have performed molecular dynamic simulations of the thermal transport across various grain boundary orientations in graphene. They assumed a constant heat flow through the material, calculated the temperature profile and from that estimated the thermal conductivity. Interestingly, they found abrupt jumps in the temperature at the grain boundaries, which depend on the boundary orientation and grain size. The estimated grain boundary thermal conductivity is much higher than in the case of other materials with high thermal conductivity, such as nanocrystalline diamond. The results are particularly important in view of potential applications based on CVD-grown graphene. It will be interesting to see how the experiments will compare with these predictions.

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