Graphene zinc-rich primer

Conductive and optical properties

The arrangement of the carbon atoms in graphene is the same as that of the graphite monatomic layer to bond with sp hybrid orbitals, and has the following characteristics: carbon atoms have 4 valence electrons, of which 3 electrons generate sp bond, that is, each carbon atom contributes a non-bonded electron located in the pz orbital, and the pz orbital of the neighboring atom is perpendicular to the plane to form π bond. The newly formed π bond is in a half-filled state. The study confirmed that the carbon atoms in graphene have a coordination number of 3, the bond length between every two adjacent carbon atoms is 1.42×10 meters, and the Angle between the bonds is 120°. In addition to the cellular layered structure in which σ bonds are linked to other carbon atoms into hexagonal rings, the pz orbitals perpendicular to the layer plane of each carbon atom can form large π bonds (similar to the benzene ring) that run through the whole layer of multiple atoms, and thus have excellent electrical and optical properties.

Mechanical properties

Graphene is one of the strongest materials known, but it is also very ductile and can bend. Graphene has a theoretical Young's modulus of 1.0TPa and an inherent tensile strength of 130GPa. Reduced graphene modified by hydrogen plasma also has very good strength, with an average modulus of 0.25TPa greater. The graphite paper composed of graphene sheets has many holes, so the graphite paper is very brittle. However, the oxidized functional graphene is made into graphite paper from the functional graphene, which is extremely strong and strong.

Electronic Effects

The carrier mobility of graphene at room temperature is about 15,000 cm/(V·s), which is more than 10 times that of silicon materials and more than twice that of indium antimonide (InSb), the substance with the highest known carrier mobility. Under certain conditions such as low temperatures, the carrier mobility of graphene can even be as high as 250000cm/(V·s). Unlike many materials, graphene's electron mobility is less affected by temperature changes, and at any temperature between 50 and 500K, the electron mobility of a single layer of graphene is around 15,000 cm/(V·s).

Thermal Properties

Graphene has very good heat conduction properties. Pure, defect-free monolayer graphene has the highest thermal conductivity of any carbon material by far, with a thermal conductivity of up to 5300W/mK, higher than single-walled carbon nanotubes (3500W/mK) and multi-walled carbon nanotubes (3000W/mK). When it is used as a carrier, the thermal conductivity can also reach 600W/mK. In addition, the ballistic thermal conductivity of graphene can move down the lower limit of the ballistic thermal conductivity of carbon nanotubes per unit circumference and length.

Optical Properties

Graphene has very good optical properties, with an absorption rate of about 2.3% over a wide wavelength range, and appears almost transparent. Over the thickness range of several layers of graphene, the absorption rate increases by 2.3% for each additional layer of thickness. Large-area graphene films also have excellent optical properties, and their optical properties change with the change of graphene thickness. This is an unusual low-energy electronic structure for a single layer of graphene. When a voltage is applied to a double-gate bilayer graphene field-effect transistor at room temperature, the graphene's band gap can be adjusted between 0 and 0.25eV. When a magnetic field is applied, the optical response of graphene nanoribbons can be tuned to the terahertz range.

solubility

Exhibits good solubility in non-polar solvents and is super hydrophobic and super lipophilic.

Melting point

Scientists said in a 2015 study that it was around 4,125K, and there are other studies that suggest the melting point could be around 5,000 K

Other properties

Can adsorb and desorb various atoms and molecules.

Compounds

Graphene oxide

A layered material obtained by graphite oxide. After the bulk phase graphite is treated with a smoky concentrated acid solution, the graphene layer is oxidized into a hydrophilic graphene oxide, and the graphite layer spacing increases from 3.35A before oxidation to 7~ 10A. The separated graphene oxide sheet structure is easily formed by heating or ultrasonic stripping in water. XPS, infrared spectroscopy (IR), solid state nuclear magnetic resonance spectroscopy (NMR) and other characterization results show that graphene oxides contain a large number of oxygen-containing functional groups, including hydroxyl, epoxy functional groups, carbonyl groups, carboxyl groups and so on. The hydroxyl and epoxy functional groups are mainly located on the base surface of graphite, while the carbonyl and carboxyl groups are located on the edge of graphene.

Graphiane

Obtained by the reaction of graphene with hydrogen gas, is a saturated hydrocarbon with the molecular formula (CH)n, in which all carbon is sp hybrid and forms a hexagonal network structure, hydrogen atoms are bonded to carbon in alternating forms from both ends of the graphene plane, and graphiane exhibits semiconducting properties with a direct band gap.

Nitrogen-doped graphene or carbon nitride

After the introduction of nitrogen atoms into the graphene lattice to become nitrogen-doped graphene, the resulting nitrogen-doped graphene shows more excellent properties than pure graphene, in a disordered, transparent, folded gauze shape, some of the sheets are stacked on top of each other to form a multi-layer structure, showing high specific capacitance and good cycle life.

Biocompatibility

The implantation of carboxyl ions can enable the surface of graphene materials to have active functional groups, thus greatly improving the cellular and biological reactivity of the material. Compared with the tubular form of carbon nanotubes, graphene is more suitable for biomaterial research. And compared with carbon nanotubes, the edges of graphene are longer, easier to be doped and chemically modified, and easier to accept functional groups.

oxidizability

Reacts with active metals.

Reducibility

It can be oxidized in air or by oxidizing acids, by which graphene can be cut into small pieces. Graphene oxide is a layered material obtained by graphite oxidation. It is easy to form separate graphene oxide lamellar structures by heating or ultrasonic stripping in water.

Addition reaction

Using the double bonds on graphene, the desired groups can be added through addition reactions.

Stability

The structure of graphene is very stable, with a carbon-carbon bond of only 1.42. The bonds between the carbon atoms inside the graphene are flexible, and when an external force is applied to the graphene, the carbon atoms bend and deform, so that the carbon atoms do not have to rearrange to adapt to the external force, which keeps the structure stable. This stable lattice structure gives graphene excellent thermal conductivity. In addition, electrons in graphene do not scatter as they move through their orbits due to lattice defects or the introduction of foreign atoms. Because the interatomic forces are so strong, at room temperature, even when the surrounding carbon atoms collide, the electrons inside graphene are very little disturbed.