Graphene: The King of New Materials in the 21st Century

Graphene is a new carbon material formed by the stacking of single-layer carbon atoms into a two-dimensional honeycomb lattice. The thickness of a single layer of graphene is 0.34 nanometers, which is only one two-hundred-thousandth the thickness of a human hair. It boasts superior electrical conductivity, thermal conductivity, and mechanical properties, surpassing those of common materials like gold, silver, copper, and iron, earning it the title of "King of New Materials for the Twenty-First Century." Graphene has broad application prospects in precision instruments, batteries, energy storage, heating, and other fields. 1. Sources of graphene

The name graphene comes from its structural characteristics. It is a flat film of carbon atoms with sp² hybrid orbitals forming a hexagonal honeycomb lattice, only one carbon atom thick. This unique structure gives graphene many extraordinary properties.

2. Classification of graphene

According to different classification criteria, graphene can be divided into several types. The following are the common classification methods:

(1) Classification by floor

Single-layer graphene: a layer of carbon atoms in a hexagonal honeycomb structure that is periodically packed tightly, with a thickness of one atomic layer.

Double graphene: composed of two layers of carbon atoms in different stacking modes (such as AB stacking, AA stacking).

Few-layer graphene: consists of three to ten layers of carbon atoms and is usually stacked in different ways.

Multilayer graphene: composed of carbon atoms from more than 10 layers to less than 10nm, and usually in different stacking modes.

(2) Classification according to functional form

Graphene oxide: Hydroxyl groups are introduced by chemical methods to make it hydrophilic and have low electrical conductivity.

Hydrogenated graphene: Introducing hydrogen atoms into graphene to make it magnetic.

Fluorinated graphene: Fluorine is added to the surface or edge of graphene for specific applications.

Nitrogen-doped graphene: Nitrogen atoms are introduced into the graphene lattice to exhibit better performance than pure graphene.

(3) Classification by form

Graphene film: prepared by chemical vapor deposition and other methods, it has the advantages of transparency, conductivity and flexibility, and is widely used in electronics, photonics and sensors.

Graphene powder: It is obtained by crushing natural graphite by physical or chemical methods. It is mainly used in coatings and lithium ion batteries.

Graphene nanosheets: Thickness between 1 and 3 nanometers, size in the range of 100 nanometers to 100 microns, commonly used in composites and nanotechnology.

Graphene quantum dots: Graphene nanostructures with specific size and shape for optoelectronic and biomedical applications.

Graphene nanoribbon: A ribbon-like material of graphene with a specific edge structure that exhibits unique physical properties.