Graphene

This tiny sheet is made of carbon.

It is shaped like a honeycomb. The atoms lock together in a flat pattern.

It is the thinnest thing in the world. One sheet is only one atom thick.

This material is very, very strong. It is the strongest thing ever measured.

It can also carry electricity well. It is almost clear like glass.

Scientists used sticky tape to find it. This helped them win a big prize.

Graphene is a special kind of carbon. Carbon is a common element found in nature. You might know carbon as diamond or graphite. Graphite is the soft stuff in your pencil.

Graphene is a single layer of carbon atoms. These atoms lock together in a flat sheet. The pattern looks like a honeycomb. It is the thinnest material in the world. One sheet is only one atom thick.

This material has many cool powers. It is very strong. In fact, it is the strongest material ever measured. It can also carry electricity very well. A single sheet is nearly clear. This is because it lets most light pass through.

Scientists used a simple way to find it. In 2004, Andre Geim and Konstantin Novoselov used sticky tape. They used the tape to pull layers from graphite. This is called the Scotch tape technique. Their work was so important that they won the Nobel Prize in Physics in 2010.

Graphene is a very special type of carbon. Carbon is an element found in many things in our world. You might know carbon as the hard diamond or the soft graphite in a pencil.

Graphene is a single layer of carbon atoms. It is known as the thinnest two-dimensional material in the world. A single sheet is only one atom thick. This makes it very different from the thick chunks of carbon we usually see.

To understand how it works, imagine a flat sheet made of tiny building blocks. In graphene, these carbon atoms lock together in a pattern. They form a honeycomb lattice, which looks like the shape of a bee's nest.

Each atom is connected to three neighbors by strong bonds. These bonds help create a very stable structure. When many hundreds of these layers stack on top of each other, they become graphite.

A single sheet is nearly clear because it lets most light pass through. However, stacked graphite looks black because it absorbs all visible light.

Scientists have been studying these structures for a long time. In 1947, a physicist named P. R. Wallace suggested that carbon could exist in sheets. Later, in 1986, a chemist named Hanns-Peter Boehm used the name "graphene."

He used the name to describe single sheets found in graphite. This name comes from "graphite" and a suffix that shows how the atoms are bonded. It took many years of research to truly understand how these single layers behave.

In 2004, two scientists named Andre Geim and Konstantin Novoselov changed everything. They worked at the University of Manchester in England. They used a very simple tool to find graphene: adhesive tape.

This method is often called the "Scotch tape technique." They pulled thin layers from a piece of graphite until they had just one layer left. For this amazing work, they won the Nobel Prize in Physics in 2010.

Today, people are looking for many ways to use graphene. It is the strongest material ever measured on a microscopic scale. It is also very good at carrying electricity.

Because of this, researchers study it for use in electronics and electric batteries. In 2012, the global market for graphene was worth $9 million. Scientists are still working hard to find ways to make it in large amounts for everyone to use.

Graphene is a unique form of the element carbon. It is a carbon allotrope, which means it is a version of carbon with a different structure. Specifically, it is a single layer of atoms arranged in a two-dimensional honeycomb planar nanostructure. This material is considered the thinnest two-dimensional material in the world. While carbon is commonly found in forms like diamond or graphite, graphene exists as a single-atom-thick sheet.

The structure of graphene is defined by how its atoms are bonded. Each carbon atom is connected to three nearest neighbors through sigma bonds, or σ-bonds. These bonds are formed by the overlap of sp2 hybrid orbitals. The remaining outer-shell electron occupies a pz orbital that points perpendicularly away from the sheet. These orbitals create delocalized pi bonds, or π-bonds, which extend over the entire sheet. This bonding creates a valence band that touches a conduction band. Because of this, graphene acts as a semimetal with very unusual electronic properties.

Graphene is characterized by several extraordinary physical properties. On a microscopic scale, it is the strongest material ever measured. It also possesses exceptionally high electrical conductivity and high tensile strength. Despite being a solid material, a single sheet is nearly transparent. It only absorbs approximately 2.3% of visible light. In contrast, graphite is made of many graphene layers stacked together. Because graphite absorbs all visible light wavelengths, it appears black to the eye.

The history of graphene involves many decades of theoretical and experimental work. In 1947, the Canadian physicist P. R. Wallace first suggested that carbon could exist in sheets. He did this while researching the electronic properties of 3D graphite. Later, in 1986, the German chemist Hanns-Peter Boehm and his coworkers isolated single sheets from graphite. They gave these sheets the name "graphene," derived from "graphite" and the suffix "-ene." This suffix indicates the presence of double bonds within the carbon structure.

A major breakthrough occurred in 2004 at the University of Manchester in England. Scientists Andre Geim and Konstantin Novoselov successfully isolated and characterized graphene. They used a method called micro-mechanical cleavage, often called the "Scotch tape technique." They used adhesive tape to pull thin layers from a piece of graphite. They then transferred these flakes onto a silicon wafer with a thin silicon dioxide layer. This setup allowed them to study the material's properties effectively. For these groundbreaking experiments, Geim and Novoselov received the Nobel Prize in Physics in 2010.

Measuring graphene reveals just how small and light it is. The molecular bond length in the lattice is 0.142 nanometers. A single hexagonal unit of graphene has an area of 0.052 square nanometers. Each unit contains two carbon atoms with a combined mass of 0.000000000000000000000036 milligrams. This means the two-dimensional density is 0.77 milligrams per square meter. To visualize this, one kilogram of graphene would cover 131.2 hectares.

Today, scientists are working to move graphene from the lab to the real world. In 2012, the global graphene market was valued at $9 million. Most of this demand comes from research into semiconductors, electronics, electric batteries, and composites. In 2014, the National Graphene Institute was established at the University of Manchester with £60 million in funding. While small amounts are easy to produce, making large quantities is difficult. Companies struggle with cost-effectiveness and quality control during mass production. However, the search for commercial uses continues in many different scientific fields.