Technological advances have been dependent on discovering new materials and realizing their applications. Ever since man discovered metal, there has been a race to discover or synthesize stronger and sturdier materials for use. Starting with the discovery of bronze then moving to iron and finally steel, we have had some immensely revolutionary discoveries till date. However, none of these discoveries may have had as much impact as the discovery of Graphene.
What is Graphene?
In simple terms, a graphene is a form of carbon whose basic structure made from one sheet of carbon atoms organized in a honeycomb pattern. It is classified as a semi-metal and forms the base structure for several carbon-based substances, including diamond, graphite, carbon nanotubes, charcoal, and fullerenes.
You can think of graphene as being one large molecule with its indefinite number of carbon atoms arranged in a hexagonal lattice.
There are several unique properties of graphene which are not seen together in any other material known to man. Not only is graphene remarkably stronger than the most robust industrial-grade steel, but it is also having a superb conductivity for heat and electricity and shows a remarkable ability to withstand intense temperature, pressure, and electricity. Despite all these strong properties, the material is practically so thin (only 1 atom-thick) that it appears utterly transparent to the naked eye.
How does Graphene look?
Graphene could be best imagined as a single-layered sheet of carbon atoms where each atom is attached to accurately 3 adjacent carbon atoms with sp²-hybridized bonding. Every individual carbon atom in this structure has 4 bonds in total – 1 σ-bond with 3 neighboring carbon atoms and 1 π-bond which restricted to a single plane.
This forms a perfect hexagonal lattice, much similar to the honeycomb we see. It is an entirely 2-dimensional structure, which makes it extremely thin, and completely transparent.
What are the different Types of Graphene?
Thanks to the impressive and unique properties of graphene we have the know-how to develop different types of graphene today. Authentic graphene exists typically as a mono-layered sheet of carbon atoms. It can use in its original form, or it can also be floated off of a substrate and reposted on another material or substrate reasonably easily.
Some of the more common types of graphene include:
- Graphene oxide
- Graphene nano-ribbons
- Graphene nano-platelets
- Graphene quantum dots
- Graphene ink
- Graphene masterbatches
- Graphene paste
- Graphene powder
How is Graphene made?
Graphene does not occur in its original form but needs to be synthesized artificially. There are 3 techniques commonly used to synthesize the material, namely:
- Mechanical cleavage from natural graphite
- Chemical/Plasma Exfoliation from natural graphite
- Chemical Vapor Deposition
What are the Properties of Graphene?
Graphene exhibits properties that are incredibly unique and is shared by none other single material that we know of today.
Let’s check out the impressive properties of graphene and learn what makes this material truly revolutionary for advancing current material science and technology:
Electronic Properties of Graphene
Graphene is considered to be a zero-gap semiconductor although it displays impressive electron mobility when in average temperature. The movement of electrons within the material are incredibly fluid and free as the entire material possesses a delocalized pi-electron bonding system for its carbon atoms.
Also, as there is no band-gaps present, as the pi-electrons overlap one another, this further facilitates the free and fluid movement of electrons in graphene without the need of adding extra energy into the system. These impressive electronic properties of graphene make the electrons within it act almost like photons, as far as their movement is concerned.
Thermal Properties of Graphene
Graphene, besides exhibiting impressive electronic properties also displays excellent thermal properties also. Thanks to its uniform and well-connected structure, graphene can conduct heat energy excellently within a single plane. Although inter-planar heat conductivity proved to be a problem initially this was soon overcome by simply adding other nano-materials, such as carbon nanotubes, to help boost heat conductivity between two different planes.
Mechanical Properties of Graphene
These are the impressive mechanical properties of graphene that give it the name ‘Wonder Material’:
Graphene exhibits incredible strength and is merely the most substantial material known to man currently. It has remarkable tensile strength and is exceptionally lightweight too.
This proves excellent when using graphene as a means to strengthen any other composite material considerably.
Graphene has extreme flexibility thanks to the repeating sp²-hybridized bonds connecting its single carbon atoms to each other in a perfect hexagonal lattice. Despite its extremely flexible nature, has sufficient rigidity and is stable enough to withstand changes in its formation and addition of other ions around it.
What are the Applications of Graphene?
These are some of the top current and potential applications of graphene, credit to the impressive and unique properties of graphene:
- Sensors – The single-atom plane of graphene allows it to detect even the smallest change in the environment, making it extremely useful for use in sensors.
- Batteries – The use of graphene to replace conventional anodes and cathodes in conventional power storage devices can significantly improve power storage technology recognition to its different electrical conductivity and optimally-exposed surface area.
- Composites – Using graphene to enhance the conventional structural composites not only makes them stronger but hugely reduces their weight as well.