Fig. 4
Typical TEM images and electron diffraction of the prepared graphene flakes. a Mono-layer graphene flake with folded edge, b magnified image of the blue box in image (a), c electron diffraction of the selected black box in image (a), d a bilayer graphene flake, e a trilayer graphene flake, f a five-layer graphene flake, g several individual graphene flakes, h distribution of number of layers (obtained from TEM analysis of at least 100 graphene flakes)