Graphene is an sp squared hybrid connection of carbon atoms tightly packed into a single two-dimensional honeycomb lattice structure of the new material, with excellent electrical and optical properties.
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Graphene has excellent optical, electrical and mechanical properties, it has important application prospects in materials, micro-nano processing, energy, biomedical and drug transfer, and is considered a revolutionary material of the future.
Graphene was successfully separated from graphite by micromechanical stripping method by physicists Andre Geim and Konstantin Novoselov of the University of Manchester in the United Kingdom, so they jointly won the 2010 Nobel Prize in Physics. The common methods of graphene powder production are mechanical stripping method, redox method, SiC epitaxial growth method, and the thin film production method is chemical vapor deposition (CVD).
Graphene is one of the materials with the highest known strength, and it also has good toughness and can be bent. The theoretical Young’s modulus of graphene is 1.0TPa and the inherent tensile strength is 130GPa. The reduced graphene modified by hydrogen plasma also has very good strength, with an average modulus of 0.25TPa. The graphite paper composed of graphene sheets has many holes, so the graphite paper is very brittle. However, it is oxidized to obtain functionalized graphene, and then made of functionalized graphene into graphite paper will be extremely strong and tough.
Graphene has very good thermal conductivity. The thermal conductivity of pure flawless single-layer graphene is up to 5300W/mK, which is the highest carbon material so far, higher than single wall carbon nanotubes (3500W/mK) and multi wall carbon nanotubes (3000W/mK). When it acts as a carrier, the thermal conductivity can also reach 600W / mK. Moreover, the ballistic thermal conductivity of graphene can shift down the lower limit of the ballistic thermal conductivity of carbon nanotubes per unit circumference and length.
Graphene is chemically similar to graphite in that it can adsorb and desorb a variety of atoms and molecules. When these atoms or molecules act as donors or acceptors they can change the concentration of graphene carriers, while the graphene itself remains very conductive. But when other substances are adsorbed, such as H and OH-, some derivatives will be produced, which will make the conductivity of graphene worse, but no new compounds will be produced. … Therefore, graphite can be used to infer the properties of graphene. For example, the generation of graphane is based on two-dimensional graphene, adding one more hydrogen atom to each carbon atom, so that the sp2 carbon atoms in graphene become sp3 hybridization. Soluble fragments of graphene can be prepared in the laboratory by chemical modification of graphite.