Computational Dynamics of Metal-Carbon Interface-- Key to Controllable Nanotube Growth.

摘要

During this final year of the project we have completed an extensive analysis of the energy landscape for the nanotube caps to elucidate its role in the chiral distribution at the nucleation stage of nanotube growth, as described in a submitted paper. Massive computations performed on about 5000 topologically distinguishable caps with precise classical potential (additionally validated on a subset of approximately 100 cap computed with density functional theory methods) show relatively flat landscape, which should not affect chiral selectivity. Further, we completed the first release of our quantitative nanoreactor diagram (or model). Through detailed description of the catalyst-carbon interface, defects energies, and growth rate, this approach makes predictions of nanotube distribution or graphene sheet shape, verifiable experimentally. Important findings in experimental growth provide strong support to the step-flow approach augmented by DFT computations. This allowed us to readily calculate the rate of nanotube or graphene growth, on different catalyst metals such as Fe, Ni, Co, Cu. We also completed our study of cooperative behavior in growth of nanotube forests, their simulated kinetics with the account for the lateral forces and feedback mechanism.