physics

Graphene

Graphene is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Graphene rather than just read about it. In short: Graphene () is a variety of the element carbon which occurs naturally in small amounts. In graphene, the carbon forms a sheet of interlocked atoms as hexagons one carbon atom thick.

Key takeaways

Graphene belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Graphene to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Graphene from memory before moving on to harder problems.

Reference excerpt

Graphene () is a variety of the element carbon which occurs naturally in small amounts. In graphene, the carbon forms a sheet of interlocked atoms as hexagons one carbon atom thick. The result resembles the face of a honeycomb. When many hundreds of graphene layers build up, they are called graphite. In technical terms, graphene is a carbon allotrope consisting of a single layer of atoms arranged in a honeycomb planar nanostructure. The name "graphene" is derived from "graphite" and the suffix -ene, indicating the presence of double bonds within the carbon structure. Graphene is known for its exceptionally high tensile strength, electrical conductivity, transparency, and being the thinnest two-dimensional material in the world. Despite the nearly transparent nature of a single graphene sheet, graphite (formed from stacked layers of graphene) appears black because it absorbs all visible light wavelengths. On a microscopic scale, graphene is the strongest material ever measured.

The existence of graphene was first theorized in 1947 by Philip R. Wallace during his research on graphite's electronic properties, while the term graphene was first defined by Hanns-Peter Boehm in 1987, when he and coworkers isolated single sheets from graphite. In 2004, the material was isolated and characterized by Andre Geim and Konstantin Novoselov at the University of Manchester using a piece of graphite and adhesive tape. In 2010, Geim and Novoselov were awarded the Nobel Prize in Physics for their "groundbreaking experiments regarding the two-dimensional material graphene". While small amounts of graphene are easy to produce using the method by which it was originally isolated, attempts to scale and automate the manufacturing process for mass production have had limited success out of concern for cost-effectiveness and quality control. The global graphene market was $9 million in 2012, with most of the demand from research and development in semiconductors, electronics, electric batteries, and composites. In 2022, the graphene market reached an estimated global annual revenue of $380 million. The IUPAC (International Union of Pure and Applied Chemistry) advises using the term "graphite" for the three-dimensional material and reserving "graphene" for discussions about the properties or reactions of single-atom layers. A narrower definition, of "isolated or free-standing graphene", requires that the layer be sufficiently isolated from its environment, but would include layers suspended or transferred to silicon dioxide or silicon carbide.

History

Structure of graphite and its intercalation compounds In 1859, Benjamin Brodie noted the highly lamellar structure of thermally reduced graphite oxide. Researchers used X-ray crystallography in an attempt to determine the structure of graphite. The lack of large single crystal graphite specimens contributed to the independent development of X-ray powder diffraction by Peter Debye and Paul Scherrer in 1915, and Albert Hull in 1916. However, neither of their proposed structures was correct. In 1918, Volkmar Kohlschütter and P. Haenni described the properties of graphite oxide paper. The structure of graphite was successfully determined from single-crystal X-ray diffraction by J. D. Bernal in 1924, while subsequent research tweaked the unit cell parameters. The theory of graphene was first explored by P. R. Wallace in 1947 as a starting point for understanding the electronic properties of 3D graphite. The emergent massless Dirac equation was separately pointed out in 1984 by Gordon Walter Semenoff, and by David P. Vincenzo and Eugene J. Mele. Semenoff emphasized the occurrence in a magnetic field of an electronic Landau level precisely at the Dirac point. This level is responsible for the anomalous integer Quantum Hall effect.

… excerpt ends here. Continue reading the full article.

Illustrations

Graphene: Photograph of a suspended graphene membrane in transmitted light. This one-atom-thick material can be seen with the naked eye because it absorbs approximately 2.3% of light.[5][6] — Photograph of a suspended graphene membrane in transmitted light. This one-atom-thick material can be seen with the naked eye because it absorbs approximately 2.3% of light.[5][6]

Worked examples

Example 1 — a first encounter with Graphene

Start with the simplest possible case. Write down what Graphene claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Graphene before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Graphene ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Graphene

In research: Graphene appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Graphene in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Graphene is common in secondary-school and first-year university syllabi. It links to neighbouring topics 21st-century inventions, Aromatic compounds, Graphene, so understanding it makes those chapters shorter.
In everyday life: Look for Graphene outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Graphene in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Graphene means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Graphene out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Graphene in simple terms?

Graphene () is a variety of the element carbon which occurs naturally in small amounts. In graphene, the carbon forms a sheet of interlocked atoms as hexagons one carbon atom thick.

Why does Graphene matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Graphene?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Graphene.