In Brief
  • Researchers have paired extremely small diamonds known as diamondoids with sulfur and copper atoms to create electrical wires only three atoms wide, the thinnest size possible.
  • These tiny electrical wires could be integrated into electricity-generating fabrics, optoelectronic devices, and even superconducting materials.

Molecular LEGOs

While you aren’t likely to find a diamond that contains only 10 atoms and weighs less than a billionth of a billionth of a carat on any engagement rings, these extremely small diamonds known as diamondoids are very useful in laboratories. They consist of interlocking cages of carbon and hydrogen, like LEGO building blocks taken to the molecular level, and because they are so small, they can do things regular diamonds can’t.

Back in 2002, scientists achieved a breakthrough in diamondoid research when they found a way to isolate and purify larger diamondoids, giving them access to a wider variety of shapes and sizes. They’ve since used these 99-percent-pure diamondoids to improve electron microscope images, coat computer chips, and now, create ultra-thin electrical wires.

Scientists from Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory (SLAC) have paired diamondoids with sulfur and copper atoms to create electrical wires that are only three atoms wide, the thinnest in history. The results have been published in Nature Materials.

This is the first demonstration of a nanowire with a solid crystalline core with good electronic properties, co-author Nicholas Melosh told Phys.org. The best part is that the process they developed is very easy and fast. “The process is a simple, one-pot synthesis. You dump the ingredients together and you can get results in half an hour,” says study lead author Hao Yan. “It’s almost as if the diamondoids know where they want to go.”

Image: SLAC National Accelerator Laboratory
An animation of diamondoids self-assembling with sulfur and copper atoms (yellow and brown spheres). Image: SLAC National Accelerator Laboratory

New Materials on the Horizon

According to the study’s press release, this ability to shape and control materials accurately down to the atomic level could be useful in a variety of ways. The tiny electrical wires could be integrated into electricity-generating fabrics, optoelectronic devices, and even superconducting materials that would be able to conduct electricity without any loss.

Materials on the small scale can retain extraordinary properties that are lost when they are composed in bulk. The researchers believe taking advantage of these properties using their assembly technique could lead to entirely new types of materials for entirely new uses.

“This method gives us a versatile toolkit where we can tinker with a number of ingredients and experimental conditions to create new materials with finely tuned electronic properties and interesting physics,” said Melosh.

Fuzzy white clusters of nanowires on a lab bench, with a penny for scale. Assembled with the help of diamondoids, the microscopic nanowires can be seen with the naked eye because the strong mutual attraction between their diamondoid shells makes them clump together, in this case by the millions. At top right, an image made with a scanning electron microscope shows nanowire clusters magnified 10,000 times. Credit: SEM image by Hao Yan/SIMES; photo by SLAC National Accelerator Laboratory
The nanowires created with diamondoids, sulfur, and copper atoms, as compared to a penny. Credit: SEM image by Hao Yan/SIMES; photo by SLAC National Accelerator Laboratory