Microstructures of alternative TCE materials: e, Scanning electron microscopy image of a Cu grid with a line width of 200 nm (ref. 41). f, Scanning electron microscopy image of an Ag nanowire network (mass density 93 mg m−2)77. g, Transmission electron microscopy cross-sections of graphene layer stacks (bilayer, triple and multiple layers). h, Optical microscope picture of CVD-grown graphene, transferred to a 300-nm-thick SiO2 layer85. Note the graphene grain sizes of around 10 μm and the ripples (inset) in the graphene layers Home