Scientists have created a new material that can be fabricated like a plastic but conducts electricity like a metal, going against all known rules for conductivity and paving the way for a new class materials that may even change the way electronics are made, they said. A team of scientists in the lab of Associate Professor of Chemistry John Anderson at the University of Chicago made the material, which still conducts electricity despite having molecular fragments that are jumbled and disordered.
Typically, conducting metals such as copper, gold, or aluminum or organic materials synthesized for this purpose are composed of straight, closely packed rows of atoms or molecules that easily allow electrons to flow. These materials are essential if you’re making any kind of electronic device but—at least in the case of organic materials—can sometimes lack stability.
The new material blows that theory wide open with a material with a disordered structure that still conducts ions, paving the way for a completely new direction for conductive materials and even materials science itself, Anderson said in an article in uchicago news. “In principle, this opens up the design of a whole new class of materials that conduct electricity, are easy to shape, and are very robust in every-day conditions,” he said.
Surprising Materials Discovery
The discovery of the new material began several years ago when a researcher in Anderson’s lab—Jiaze Xie, who was a PhD student at the time and is now at Princeton University—began experimenting by stringing nickel atoms like pearls into molecular beads made of carbon and sulfur. Tests done using the material showed that it easily and significantly conducted electricity, which—combined with its high stability—took the researchers by complete surprise, they said.
“We heated it, chilled it, exposed it to air and humidity, and even dripped acid and base on it, and nothing happened,” Xie said in the article, noting that these properties are extremely helpful for real-world application of conducting materials.
What seemed even more surprising is that researchers couldn’t find a solid theory to explain why the disordered molecular structure of the material allowed for its unique properties, Anderson said. So the team collaborated with scientists around the world on tests, simulations, and theoretical work to try to figure it out.
Eventually, they came up with the conclusion that the material forms layers, similar to the sheets of noodles in a lasagna. Even if the sheets rotate sideways, altering the equilibrium of the stack, electrons can still move freely in horizontal or vertical directions as long as the pieces are touching, they said.
New Directions in Electronics
Still, even realizing this, researchers said that the resulting material—which Anderson calls “conductive Play-Doh”—is unprecedented for something that conducts electricity so well. “You can smush it into place and it conducts electricity,” he said.
Researchers published a paper on their work in the journal Nature.
The discovery represents a new design principle for the development of electronics technology, including in its options for processing, researchers said. For example, metals typically have to be melted in order to be made into the right shape for a processor or device, which limits what can be made with them because other components in the system also need to have similar capacity to withstand heat. The new material, however, doesn’t have this restriction because it can be made at room temperatures, researchers said. And because of its stability, scientists can use it for requirements in which a device or pieces of the device must withstand heat, acid or alkalinity, or even humidity—something that has previously limited options for developing novel technology, they said.
The team is now exploring the different forms and functions that the material might make—such as 2D, 3D, or porous—which can potentially alter its functionality, Xie noted. “[We can] even introduce other functions by adding different linkers or nodes,” he added.