It is noteworthy that the cell dimension of the graphene aerogel is about hundreds of micrometers due to relative low freezing rate during the recasting process.
Moreover, sonication induced scissions cause the lateral dimensions of the exfoliated graphene flakes to drop drastically.
A first indication of the nanometric dimensions of the dispersed graphene particles was provided by the occurrence of the Tyndall effect[25].
Unfortunately, very few reports provided systematic analysis on statistical distribution of thickness and lateral dimension of the exfoliated graphene sheets to figure out the exact scalability of each method.
The first mentioned mode attests the high temperature desorption of carboxyl groups located at the edges of the GO flakes, and the increased amplitude of the last mentioned mode indicates the increase in dimensions of unoxidized graphene areas.
Atomic force microscopy (AFM) is also a very good tool to evaluate the lateral dimensions and number of layers of the graphene nanosheets.
A valuable solution to this problem is to engineer a band gap in the energy spectrum of graphene for example confining the physical dimensions of graphene into nanoribbons [24 28] or by chemical functionalisation [29 46].
The chemical composition and dimensions of graphene are similar to those of CNTs, but the shape of graphene is completely different from that of CNTs (planar versus cylindrical) [ 32].
So, changing the flow of H2 gas during growth steps affects the morphology of graphene film such as the sizes, shapes, and dimensions of graphene grain boundaries (e.g., edge, pits, zigzag) [19, 22].
