A transparent material has achieved the highest conductivity in its class promising advanced technological uses including solar cells and touch screens.
The material bucks the trend of materials that have what is known as a wide ‘bandgap’ – which means that light can pass through it – in that it still possesses high conductivity as well.
“The high conductivity and wide bandgap make this an ideal material for making optically transparent conducting films which could be used in a wide variety of electronic devices, including high-power electronics, electronic displays, touch screens and even solar cells in which light needs to pass through the device,” said lead researcher, Bharat Jalan, professor of chemical engineering and materials science at the University of Minnesota.
Most transparent conductors use the chemical element indium but its cost has increased over the last 20 years adding to the cost of display technology. This has spurred the search for alternative materials that work as well as indium-based transparent conductors.
The research team created a transparent conducting thin film by growing a thin film barium stannate. This is a combination of the relatively inexpensive elements barium, tin and oxygen though they replaced tin source with a chemical precursor of the alloy which has properties that enhanced its chemical reactivity.
“We were quite surprised at how well this unconventional approach worked the very first time we used the tin chemical precursor,” said chemical engineering and materials science graduate student Abhinav Prakash.
“It was a big risk, but it was quite a big breakthrough for us.”
The research was funded by the National Science Foundation (NSF), Air Force Office of Scientific Research (AFOSR), and the US Department of Energy.
“Even though this material has the highest conductivity within the same materials class, there is much room for improvement in addition to the outstanding potential for discovering new physics if we decrease the defects. That’s our next goal,” explained Jalan.