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The world’s thinnest Christmas tree has the size of an atom

The world’s thinnest Christmas tree, with the thickness similar to that of a single atom, has been developed by a team of researchers from the Technical University of Denmark (DTU). The tree is made from graphene, a sheet form of carbon that conducts electricity ten times more effectively than copper. At only a third of a nanometer (one billionth of a meter) thick, the graphene Christmas tree is 30,000 times thinner than kitchen film.

Known as a scientific “wonder material,” graphene consists of a single, two-dimensional layer of carbon atoms arranged in a honeycomb-like structure. It is made by chemically processing graphite (a cheap material found in the lead of pencils and the crystalline form of carbon), and is more robust, stiffer, and better at conducting electricity and heat than any other material. Graphene has great potential for the manufacturing of flexible electronics, solar panels, water filters, and biosensors.

“Although the starting point is carbon, just like the graphite in a pencil, graphene is at the same time even more conductive than copper,” explained study lead author Peter Bøggild, an expert in Nanotechnology at DTU. 

The material is usually “grown” on copper foil at around 1,832°F (1,000°C) and is afterwards transferred by using a rebuilt lamination machine. Next, the graphene is scanned with terahertz radiation in order to ensure that it maintains its electric conductivity, which is crucial for its many potential industrial uses.

“We have taken a very significant step. We have converted a laminating machine into a so-called roll-2-roll transfer system,” said Professor Bøggild. 

“It gently lifts the graphene layer from the copper roll on which the graphene layer is grown and moves it onto plastic foil without it breaking, becoming wrinkled or dirty. When we combine this with the terahertz system, we can immediately see if the process has gone well – that is, whether we have unbroken graphene with low electrical resistance.”  

The researchers cut the “Christmas tree” from a 30-foot long roll of graphene. “Even if you could make a pencil drawing of a Christmas tree and lift it off the paper – which, figuratively, is what we have done – it would be much thicker than one atom. A bacterium is 3,000 times thicker than the graphene layer we used. That’s why I dare call this the world’s thinnest Christmas tree,” Professor Bøggild concluded.

The graphene manufacturing procedure is fully explained by Professor Bøggild and his colleagues in the journal 2D Materials.

By Andrei Ionescu, Staff Writer

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