1 research outputs found
Mass Transport through Defects in Graphene Layers
The
paper reports an experimental study of ZnTe and CuI transport
through graphene wall of SWNTs by high resolution transmission electron
microscopy. It is shown that encapsulated material evacuates the tube
through the defects in the nanotube walls, while in-tube diffusion
appears high enough to provide matter intake from the nanotube volume.
Diffusion kinetics was studied by “atoms count” resulting
in ZnTe and CuI diffusivities of 7.67 × 10<sup>–21</sup> and 1.99 × 10<sup>–20</sup> m<sup>2</sup>/s through
single defects in SWNT wall. Semiempirical and DFT modeling of potential
energy profiles for different types of defects was utilized to propose
minimal structural disturbances in a graphene layer to make possible
cross-plane transport of matter. The comparison of experimentally
observed diffusivities with calculated activation barrier heights
was carried out taking into account an effective temperature of substance
under electron beam. Neither of the defects including framework disturbance
with 5–7 defects or sp<sup>3</sup>-bound carbon atomic pairs
give rise to valuable mass-transport efficiencies through graphene
layer. Reasonable conformity of the results is only achieved with
carbon vacancy pairs in sp<sup>2</sup>-carbon layer, thus, indicating
effective transport of matter occurring through the “holes”
in graphene