Scientists Create High-Conductivity Transparent Nano-Scale Film Material

A team of researchers announced, in a study published Friday in the journal Nature Communications, that it had succeeded in creating a nano-scale material that could be used to build cheap and efficient transparent conductors.

The researchers argued that the new material, made of a compound called barium stannate, could lead to the creation of smaller, faster, and more powerful electronics, and more efficient solar cells.

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"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," lead researcher Bharat Jalan, a professor of chemical engineering and materials science at the University of Minnesota, said in a statement.

The researchers used a novel synthesis method to create the material. They first grew a thin film of barium stannate in which the elemental tin source had been replaced with a chemical precursor of tin. Doing so allowed them to exploit the unique properties of the chemical precursor, and greatly enhanced the chemical reactivity and conductivity of the material.

The thin film thus created not only had a much higher conductivity than any other material in its class, it also had a wide "bandgap" — which means light could easily pass through the material, making it optically transparent.

So far, most materials with a wide bandgap have been found to have either low conductivity or poor transparency.

"We were quite surprised at how well this unconventional approach worked the very first time we used the tin chemical precursor," study's first author Abhinav Prakash, a graduate student at the University of Minnesota, said in the statement. "It was a big risk, but it was quite a big breakthrough for us."

The technique also allowed researchers to exercise "unprecedented" control over thickness and composition of the material created. Moreover, since the process that created the new material is both reproducible and scalable, the researchers said it could eventually replace the indium-based transparent conductors that are currently used.

The discovery of the new material comes at a time when reserves of indium tin oxide — the material most commonly used in transparent conducting materials — are running low. Given that most modern technologies, including smartphones, tablets and household appliances, now come with incorporated touch screens, a replacement is urgently needed.

Since both barium and tin are significantly cheaper than indium and are much more abundant, they could help scientists move toward the ultimate goal — creation of a material with high conductivity and optical transparency at a low cost.

"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," Jalan said.