Graphene - a single atomic layer of graphite

Graphene, a single layer of carbon atoms arranged in a hexagonal lattice, with a carbon-carbon distance of 0.142 nm, has been hailed as a wonder material since its discovery in 2004 by Andre Geim and his former student Konstantin Novoselov in the University of Manchester, England.

Six years later they received the the Nobelprize for their groundbreaking experiments on graphene.

Properties

History

Electrical

• Graphit (3D): 0,000 008 Ωm

• Graphene (2D): 0,000 000 001 Ωm

• Copper: 0,000 000 017 Ωm

Thermal

• Graphit (3D): 150 W/(m•k)

• Graphene (2D): 5000 W/(m•k)

• Copper: 400 W/(m•k)

Mechanical

• Graphit (3D): 4•10⁷ Pa

• Graphene (2D): 1•10¹¹ Pa

• Steal: 7•10⁸ Pa

Pro's & Con's

Possible Usage

Electronics: Graphene transistors can potentially outperform silicon, leading to faster, more efficient electronic devices.

Energy Storage: In batteries and super capacitors, graphene can enhance capacity and reduce charging times, paving the way for longer-lasting and quicker-charging batteries.

Composites: Adding graphene to materials like plastics, metals, or ceramics can significantly improve their strength and durability.

Medical: Its biocompatibility and conductivity make graphene ideal for developing advanced medical devices, sensors, and even targeted drug delivery systems.

Sensors: Graphene’s sensitivity to various substances makes it perfect for creating highly accurate sensors for environmental monitoring, health diagnostics, and more.

Possible Application

Micromechanical exfolation

• peeling systematically ordered pyrolytic graphite with the use of adhesive tape

• graphene is sliced into various flakes of few layers by continuously peeling the multi-layer graphene

• not suitable for large productions and a homogeneous and precise application

Liquid-Phase exfolation

• using solvent like acetic acid, sulfuric acid and hydrogen peroxide, to exfoliate graphite through ultrasonication

• used to create graphene nanoribbons, but large-scale growth of graphene is difficult task in this method

Chemical vapor deposition

• in this process, nickel and copper used for large scale production of graphene

• during the process film of metallic catalyst deposits on the substrate

• chemical etching is performed on the deposited material on the substrate

• after chemical etching, a mixture which containing the carbon is passed into the reaction chamber -> highest quality possible

Flame synthesis

• widely used mass production method for making nano particles

• method is not well adopted for production of graphene as compared to chemical vapor deposition

• has potential to produce graphene economically

Pulsed laser deposition

• laser energy source is outside the chamber; and chamber is maintained ultrahigh vacuum

• material is deposited by at an angle of 45° by stoichiometry transfer between ablated target and substrate material

• substrates are added to its surfaces parallel to the target at distance of 2–10 mm

• main advantages is low temperature growth rate achieved such that high-quality graphene made without defects

Extra: Twistronics

• Chances of combining 2D-Materials to build a 3D-Material -> will create Interfaces wich can have interesting functionalities (similar to pn-junction)

• Moiré-patterns on atomic scale when combining two layers of graphene in an angle of 16° and 5,9°

  -> the pattern mirrors the hexagonal structure of carbon atoms

The „magic“ angle of 1,1°

• Two layers of graphene can conduct the electron without any resistance

• This can be accomplished by twisting these two layers at 1,1°

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