New Transparent Film Conducts Electricity

A University of Minnesota led research team has discovered a new nano-scale thin film material with the highest-ever conductivity in its class. The new material could lead to smaller, faster, and more powerful electronics, as well as more efficient solar cells.

The researchers are said what makes this new material so unique is that it has a high conductivity, which helps electronics conduct more electricity and become more powerful. But the material also has a wide bandgap, which means light can easily pass through the material making it optically transparent. In most cases, materials with wide bandgap, usually have either low conductivity or poor transparency.

Bharat Jalan, a University of Minnesota chemical engineering and materials science professor and the lead researcher on the study noted, “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.”

The discovery research paper has been published in Nature Communications, an open access journal that publishes high-quality research from all areas of the natural sciences.

Currently, most of the transparent conductors in our electronics use a chemical element called indium. The price of indium has gone up tremendously in the past few years significantly adding to the cost of current display technology. As a result, there has been immense efforts to find alternative materials that work as well, or even better, than indium-based transparent conductors.

In this study, researchers found 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 elemental tin source with a chemical precursor of tin. The chemical precursor of tin has unique, radical properties that enhanced the chemical reactivity and greatly improved the metal oxide formation process. Both barium and tin are significantly cheaper than indium and are abundantly available.

University of Minnesota chemical engineering and materials science graduate student Abhinav Prakash, the first author of the paper said, “We were quite surprised at how well this unconventional approach worked the very first time we used the tin chemical precursor. It was a big risk, but it was quite a big breakthrough for us.”

Jalan and Prakash said this new process allowed them to create this material with unprecedented control over thickness, composition, and defect concentration and that this process 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 added that it was the structurally superior quality with improved defect concentration that allowed them to discover high conductivity in the material. They said the next step is to continue to reduce the defects at the atomic scale.

Looking ahead Jalan said, “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.”

This kind of research is welcome indeed. Materials that enable more ideas and concepts that need less power thus smaller batteries and less charge time are part of the foundation for a better future.