Research finds alternative to insufficient indium

Rare earth elements.

A research team has found a low-cost and sustainable way to replace indium in multiple applications including electronic devices, anti-reflection mirrors and smart architectural windows.

Indium is one of the world’s scarcest modern materials and has only been found in small deposits, usually as a by-product of zinc mining.

The rare chemical element is used in smartphones, computers and windscreen glass, but it is forecast to run out on Earth within 10 years – or earlier if demand for these products increases.

Behnam Akhavan from the University of Sydney’s School of Biomedical Engineering led the research team in developing a plasma-generated hybrid material to replace indium in these common products.

The hybrid material is made of tungsten oxide and silver – two materials more available to mine – and can flexibly coat the products mentioned.

“When you change the transparency of a wearable electronic or a smart window, an electrochromic device is doing the work,” Akhavan explained.

“Until now, these devices have typically relied on materials like rare indium to do the job. What we have created is a manufacturer’s dream: a technology that removes the need for indium and instead uses a plasma-engineered, three-layered structure that is much cheaper to produce.”

The three layers include one of silver – 10,000 times thinner than a human hair – between two nano-thin layers of tungsten oxide.

A version of the new material had been attempted in 2019, but without incorporating the silver.

By including the silver layer, the material becomes electrically conductive, allowing for the user of the product to dim or brighten it.

“These plasma-fabricated coatings can then be applied to electronic papers, smart phones and glass windows, and can be dimmed with the application of a small electrical current,” Akhavan said.

 

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