Essence

of

graphene

"Perfect" graphene

In physiochemical terms graphene is a two-dimensional layer of carbon atoms with a thickness of single atom and hexagonal "honeycomb" atom layout. It is often presented as a uniform large-dimension grid. In reality such a perfect structure does not exist, it may only be created in form of small adjacent and overlapping flakes.

Real graphene

The graphene is so unique because it combines a set of properties unseen in any previously known material. These are: mechanical strength, elasticity, thermal properties (high conductivity), transparency for the whole spectrum of electromagnetic waves, impermeability for practically all substances, biological properties, sensory capabilities, electronic properties (mainly very high electron mobility), high thermal and electrical conductivity.

Graphene properties and their significance for applications

High electron mobility at room temperature levels (≈ 130 × higher than for silicon, ≈ 25 × higher than for GaAs) and high electrical conductivity:

• High-frequency transistors, spintronics, semiconductor memory, Micro Electro-Mechanical Systems (MEMS), high-frequency electronics
• ESD, EMI and RFI coatings
• VHF antennas

Hight mechanical strength (Young modulus ≈ 100 GPa):

• Composite materials
• Very high rigidity enables pressure sensor applications

High durability for high current densities:

• Cable materials

Elasticity:

• Flexible electronics
• RFID tags

High active surface per weight unit (limit 2630 m²/g):

• Energy storage (supercapacitors, new generation cells)
• Fuel cells

High transmittance (98%) for electromagnetic radiation with flat characteristics:

• Transparent electrodes, photovoltaics, materials for laser production

High sensitivity to chemical compounds (chemical "control" of physical properties):

• Biosensors, chemical sensors
• Hydrogen storage

High thermal conductivity combined with anisotropic properties (≈ 300 W/(m×K) along the surface, ≈ 2 W/(m×K) in perpendicular direction):

• Heat/energy storage
• Heat flow management – cooling

Impermeability (if without defects):

• Coatings and paints
• Food wraps
• Layered composites

Hydrophobicity:

• Composites working in high-humidity environment

Bactericidal properties:

• Materials for sterile room construction
• Dressing materils