A team of researchers, led by scientists at the University of Minnesota, has discovered a new nano-scale thin film material with the highest-ever conductivity in its class. This new material, which is reported in a paper in Nature Communications, could lead to smaller, faster and more powerful electronics, as well as more efficient solar cells.
According to the researchers, what makes this new material so unique is that not only does it have a high conductivity, but it also has a wide bandgap, allowing light to pass easily through the material and making it optically transparent. In most cases, materials with a wide bandgap usually have either low conductivity or poor transparency.
"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, touchscreens and even solar cells in which light needs to pass through the device," explained Bharat Jalan, a University of Minnesota chemical engineering and materials science professor and the lead researcher on the study.
Currently, most of the transparent conductors in electronics use a chemical element called indium. The price of indium has generally gone up over the past two decades, which has added to the cost of current display technology. As a result, tremendous efforts have been made to find alternative materials that work as well, or even better, than indium-based transparent conductors.
"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, touchscreens and even solar cells in which light needs to pass through the device."Bharat Jalan, University of Minnesota
In this study, the researchers managed to find a solution. They developed a new transparent conducting thin film using a novel synthesis method, in which they grew a BaSnO3 thin film (a combination of barium, tin and oxygen, called barium stannate) but replaced the elemental tin with a chemical precursor of tin. This chemical precursor has unique, radical properties that enhance chemical reactivity and greatly improve the formation process for this metal oxide. Both barium and tin are significantly cheaper than indium and are abundantly available.
"We were quite surprised at how well this unconventional approach worked the very first time we used the tin chemical precursor," said University of Minnesota chemical engineering and materials science graduate student Abhinav Prakash, the first author of the paper. "It was a big risk, but it was quite a big breakthrough for us."
Jalan and Prakash said that this new process allowed them to create the material with unprecedented control over its thickness, composition and defect concentration, and should be highly suitable for a number of other material systems where the element is hard to oxidize. The new process is also reproducible and scalable.
They further added that it was the material’s structurally-superior quality, with improved defect concentration, that allowed them to discover its high conductivity. The next step is to continue to reduce the defects at the atomic scale.
"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," Jalan said.
This story is adapted from material from the University of Minnesota, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.