[Image courtesy of SLAC]
The researchers created the wires using the smallest possible bits of diamonds, making the nanowires just three atoms thin.
“In the long run, these fundamental understandings can help make, for example, more powerful superconductors used in MRIs, or fluorescent bio-markers that enables higher resolution imaging of cells and organs,” said Hao Yan, a Stanford postdoctoral researcher and lead author of the paper.
The diamondoid nanowires have solid, inorganic cores and three-atom cross-sections. The various types of atoms pull themselves together and build tiny wires that can be used for electricity generating fabric, optoelectronic devices and superconducting materials.
The basic nanowire building blocks were created using extremely small diamondoids, with single cages with only 10 carbon atoms and a sulfur atom attach to each carbon atom. Then each sulfur atom bonded to one copper ion while floating in a solution. The building blocks are attracted to each other and attach to the tips of nanowires.
“What we have shown here is that we can make tiny, conductive wires of the smallest possible size that essentially assemble themselves,” said Yan. “The process is a simple, one-pot synthesis. You dump the ingredients together, and you can get results in half an hour. It’s almost as if the diamondoids know where they want to go.”
The diamondoids used to make the wires are assembly tools that are tiny, interlocking cages of carbon and hydrogen. The SLAC laboratory removed and separated the diamondoids by size and geometry from petroleum fluids where they naturally occur. The diamondoids form an insulating shell around the wires that have a semiconducting core consisting of a combination of copper and sulfur.
“Much like LEGO blocks, they only fit together in certain ways that are determined by their size and shape,” said Stanford graduate student Fei Hua Li, who synthesized the tiny wires. “The copper and sulfur atoms of each building block wound up in the middle, forming the conductive core of the wire, and the bulkier diamondoids wound up on the outside, forming the insulating shell.”
The research team has used diamondoids in the past to make one-dimensional nanowires that grew long enough that it could be seen without a microscope. They’ve also used the wires for a variety of optoelectronics and solar applications.
The study was published in the Nature Materials journal and funded by the DOE Office of Science and the German Research Foundation.
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