Graphene Properties and History

Introduction

• Graphene is a one-atom thick layer of graphite.
• It's the fundamental building block of other allotropes like graphite, charcoal, carbon nanotubes, and fullerenes.
• Graphene is the strongest and thinnest material known.
• Graphene is an atomic-scale honeycomb lattice composed of carbon atoms.
• Graphene is a 2D crystal of carbon atoms arranged in a honeycomb lattice.
• Each carbon atom is sp² hybridized and bonded to three neighbors.

History

• A patent for graphene production was filed in 2002, titled "Nano-scaled Graphene Plates."
• In 2004, Andre Geim and Kostya Novoselov at the University of Manchester extracted single-atom-thick graphene crystals from bulk graphite.
• Geim and Novoselov received the 2010 Nobel Prize in Physics for their graphene research.

Structure

• Graphene is a 2-dimensional network of carbon atoms bonded together in a honeycomb pattern.
• The carbon atoms are bound tightly within a plane by strong bonds forming six-membered rings.
• Stacking these layers creates the well-known 3D graphite structure.
• Graphene is the basic building block for all other graphitic materials, with different dimensionalities.
• It can be transformed into 0D fullerenes, 1D nanotubes, or stacked into 3D graphite.

Mechanical Properties

• Scientists use Atomic Force Microscopy to calculate graphene's strength.
• Graphene is harder than diamond, and 300 times harder than steel.
• Graphene's tensile strength surpasses 1 TPa (teraPascal).
• It can be stretched up to 20% of its original length.

Chemical Properties

• Graphene is the most reactive form of carbon.
• Each carbon atom is exposed on two sides due to graphene's 2D structure, increasing its reactivity.
• Edge carbon atoms in graphene sheets are chemically reactive.
• Graphene burns at a low temperature (e.g., 350°C).
• It has a high ratio of edge carbon atoms compared to other carbon materials like carbon nanotubes.
• Graphene can be modified with oxygen and nitrogen containing functional groups.

Electronic Properties

• Graphene is a zero-overlap semimetal with high electrical conductivity.
• Electrons pass through graphene extremely fast, nearly 1/100th the speed of light.
• Graphene exhibits high charge carrier mobility, with reported values reaching 200,000 cm²/Vs.

Thermal Properties

• Graphene is a perfect thermal conductor.
• Its thermal conductivity is significantly higher than other carbon forms like carbon nanotubes, graphite, and diamond.
• The thermal conductivity of graphene is 5,000 W/m⋅K at room temperature.
• Graphite (3D form of graphene) has a lower thermal conductivity of approximately 1000 W/m⋅K.
• The thermal conductance of graphene is isotropic (same in all directions).

Optical Properties

• Graphene, despite its one-atom thickness, is visible to the naked eye.
• Graphene absorbs a significant amount (2.3%) of light passing through it due to its electronic properties.

Applications

• Graphene's mechanical and optical properties make it suitable for producing lightweight, strong composite materials.
• Potential for flexible displays.
• Proposed for DNA sequencing (analysis).
• Use in high-speed transistors for processors.
• Potential for transparent conducting electrodes in optoelectronic devices (touchscreens, liquid crystal displays, organic photovoltaics, and organic light-emitting diodes.).
• Possible use in graphene-based filters for desalination & alcohol production.
• Potential for use in solar cells, improving photoelectrochemical energy conversion.
• Possible application in energy storage devices (supercapacitors).
• Potential antimicrobial applications for hygiene products and packaging.
• Wide range of other potential applications including composite materials, infrared detectors, single-molecule gas detection, piezoelectric materials, energy harvesting, liquid cells for electron microscopy, thermal management materials, optical modulators, and chemical sensors.

Biomedical

• Graphene could be used to analyze DNA at an exceptionally fast pace.
• The method involves sending DNA through a tiny slit in a graphene sheet.

Integrated Circuits

• Graphene's high carrier mobility and low noise make it a viable candidate as a channel for field-effect transistors.
• 100 GHz transistors can be developed on 2-inch graphene sheets.
• Graphene-based integrated circuits handle frequencies up to 10 GHz.
• Transistors printed on flexible plastic using graphene operate at 25 gigahertz.
• Graphene enables terahertz-speed transistors.

Other Applications

• Graphene nanoribbons
• Infrared detectors
• Single-molecule gas detection
• Piezoelectric materials
• Energy Harvesting
• Composite Materials
• Liquid Cells for Electron Microscopy
• Thermal management materials
• Optical Modulators
• Chemical sensors

This quiz covers the essential properties, history, and structure of graphene, the strongest and thinnest material known. Discover how this single-atom thick layer of graphite has revolutionized materials science and earned researchers a Nobel Prize. Test your knowledge on its atomic structure and significance in modern technology.