Conductive plastic uses sandwiched materials for extra transparency
Traditional plastics are so poor at conducting electricity that they are often used to insulate against it instead, making it the shielding material of choice for things like wiring and circuit boards. But scientists have long hoped to flip the script by adding other materials to give plastic conductive properties, and one team of researchers has now put forward a promising possibility it's hoped could find uses in large touchscreens or window-mounted solar cells.
The new material was developed by electrical and computer engineers at University of Michigan, and builds on their earlier work in the area. The team had previously demonstrated how a very fine layer of silver could be added to a plastic sheet to make it conductive, though this came at a cost, reducing its transmission of light by around 10 percent.
One way to improve the light transmission of plastics is by applying anti-reflective coatings, but these don’t typically carry conductive properties. Through a careful mix of metals and multilayered materials, the researchers believe they may have addressed this shortcoming.
Their transparent, conductive plastic consists of the very fine silver and plastic layer, which also features small amounts of copper and measures just 6.5 nanometers thick. This conductive layer is sandwiched in between two "dielectric" materials, one made of aluminum oxide and the other of zinc oxide.
These promote the passage of light through the material with such effectiveness that the light transmission is greater than it would be with the plastic alone – 88.4 percent compared to 88.1 percent for the plastic on its own.
“We developed a way to make coatings with high transparency and conductivity, low haze, excellent flexibility, easy fabrication and great compatibility with different surfaces,” says Jay Guo, a professor of electrical engineering and computer science and leader of the research.
From here, the team is exploring how the material could be used as see-through conductors in solar cells that double as windows, while large interactive displays and car windshields that melt ice are other possibilities.
The research was published in the journal Nature Communications.
Source: University of Michigan