Plastic-like material conducts electricity like metal
Image credit: Dreamstime
A material that can be made like a plastic, but conducts electricity more like a metal, has been developed by scientists at the University of Chicago.
The material has molecular fragments that are jumbled and disordered, but can still conduct electricity extremely well, which goes against all of the standard rules for conductivity.
“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 everyday conditions,” said John Anderson, an associate professor of chemistry at the University of Chicago.
“Essentially, it suggests new possibilities for an extremely important technological group of materials,” said Jiaze Xie, the first author on the paper.
Conductive materials are essential in the creation of electronics and by far the oldest and largest group of conductors is the metals: copper, gold, aluminium.
About 50 years ago scientists developed a chemical treatment known as 'doping' that allowed conductors to be made out of organic materials. This is advantageous because these materials are more flexible and easier to process than traditional metals, but they are typically not very stable and can lose their conductivity if exposed to moisture or if the temperature gets too high.
Both these organic materials and traditional metallic conductors are made up of straight, closely packed rows of atoms or molecules, which means that electrons can easily flow through the material.
In developing the new material, the researchers strung nickel atoms like pearls into a string of molecular beads made of carbon and sulphur which surprisingly achieved strongly conductive properties while being very stable.
“We heated it, chilled it, exposed it to air and humidity, and even dripped acid and base on it, and nothing happened,” said Xie.
After tests, simulations, and theoretical work, the researchers believe that the material forms layers that electrons can pass through. Even if the sheets rotate sideways, electrons can still move horizontally or vertically through the material as long as the pieces touch.
The scientists believe their discovery suggests a fundamentally new design principle for electronics technology. One of the material’s attractive characteristics is new options for processing.
For example, metals usually have to be melted in order to be made into the right shape for a chip or device, which limits what you can make with them, since other components of the device have to be able to withstand the heat needed to process these materials.
The new material has no such restriction because it can be made at room temperatures. It can also be used where the need for a device or pieces of the device to withstand heat, acid or alkalinity, or humidity has previously limited engineers’ options to develop new technology.
The team is also exploring the different forms and functions the material might make.
“We think we can make it 2D or 3D, make it porous, or even introduce other functions by adding different linkers or nodes,” said Xie.
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