graphene

graphene is a single layer of carbon atoms arranged in a two-dimensional hexagonal lattice. It is the fundamental structural element of other allotropes like graphite, carbon nanotubes, and fullerenes. The material was isolated and characterized in 2004 by physicists Andre Geim and Konstantin Novoselov at the University of Manchester, work for which they were awarded the Nobel Prize in Physics in 2010. Its unique combination of properties has generated intense research across fields like condensed matter physics, materials science, and electrical engineering.

Properties

Graphene exhibits an extraordinary array of physical properties stemming from its two-dimensional structure and the sp² bonding between carbon atoms. It is renowned for its exceptional electrical conductivity, with charge carriers behaving like massless Dirac fermions, leading to very high electron mobility. Mechanically, it is one of the strongest materials ever tested, with a high tensile strength and Young's modulus. It is nearly transparent, absorbing only about 2.3% of white light, and is an excellent thermal conductor, surpassing copper and diamond. Its behavior is often studied in relation to theories like quantum Hall effect and relativistic quantum mechanics.

Production

The initial isolation of graphene was achieved using a simple technique called mechanical exfoliation, which involves using adhesive tape to peel layers from graphite. For larger-scale production, methods like chemical vapor deposition on metal substrates such as copper or nickel have become prominent. Other approaches include liquid-phase exfoliation of graphite in solvents, and growth on silicon carbide wafers through epitaxy. Research institutions like the Massachusetts Institute of Technology and companies like Graphenea and Samsung actively develop and refine these production techniques.

History

The theoretical study of graphene dates back to the 1940s, but it was long considered thermodynamically unstable. In 2004, Andre Geim and Konstantin Novoselov at the University of Manchester successfully isolated stable monolayers, a breakthrough published in the journal Science. Their work built upon earlier research on graphite and carbon nanotubes. This discovery earned them the Nobel Prize in Physics in 2010. Subsequent research has been heavily supported by entities like the European Union's Graphene Flagship and the National Science Foundation.

Applications

Potential applications for graphene are vast and span numerous industries. In electronics, it is researched for use in transistors, integrated circuits, and flexible touchscreen displays due to its conductivity and transparency. Its strength and lightness make it a candidate for advanced composite materials in the aerospace and automotive sectors. Other applications include high-performance batteries and supercapacitors for energy storage, efficient water filtration membranes, and sensitive biosensors. Companies like IBM, Intel, and Samsung are heavily invested in its commercial development.

Health and safety

Research into the potential health and environmental impacts of graphene is ongoing. Studies, some funded by agencies like the National Institute for Occupational Safety and Health, investigate the effects of nanoparticle inhalation and long-term biopersistence. Preliminary research on animal models suggests certain graphene forms could cause inflammation in the lungs, similar to other nanomaterials like asbestos or carbon nanotubes. Regulatory bodies such as the Environmental Protection Agency and the European Chemicals Agency are developing frameworks for its safe handling and disposal.

Category:Allotropes of carbon Category:Two-dimensional materials Category:Nanomaterials