World's thinnest Christmas tree

Danish scientists created a pine tree 14 centimeters long but only one-third nanometer thick from graphene.

A few years ago, a group of Canadian scientists celebrated Christmas by making a micro gingerbread house. This year, Danish scientists celebrate the holiday with a different method, by creating the world's thinnest Christmas tree from graphene, New Atlas reported on December 24.

Picture 1 of World's thinnest Christmas tree
The different versions of the Christmas tree are just one atom thick.

Graphene takes the form of a sheet of carbon atoms just one atom thick, linked together in a honeycomb structure. It is the world's thinnest and strongest man-made material, and is also a good conductor of electricity, heat, and waterproofing. These characteristics make it useful in many applications such as batteries, electronics and high-strength composites. However, a major challenge is to ensure good quality when producing on a commercial scale. This is how the tiny Christmas tree was born.

The pine tree is 14 centimeters long and only a third of a nanometer (nanometers equals one billionth of a meter) thick, cut by a team of experts at the Danish University of Technology (DTU) from a 10 meter long roll of graphene. They first "planted" graphene on a roll of reusable copper foil, then lifted the graphene out of the copper and placed it on a low-cost polymer coil for easy handling and storage.

This is the long-accepted method of producing graphene, but it is still difficult to test whether the graphene really doesn't lose any of its properties when switched from coil to coil. The DTU team of scientists solved this problem by using terahertz radiation, which is considered harmless in small doses.

Specifically, when graphene is transferred to a polymer, it must first be exposed to terahertz radio waves, then scan to see how much terahertz radiation it has absorbed. Graphene's ability to absorb radiation directly corresponds to electrical conductivity. So if the scan data shows that graphene absorbs radiation evenly, it means it has good quality.

"The Christmas tree joke hides an important breakthrough. For the first time, we have succeeded in direct quality control of the graphene layer during the transition. This is the key to achieving the characteristics. stable, reproducible and usable materials are prerequisites for the use of graphene in devices, such as electrical circuits," explains Professor Peter Boggild at DTU.