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Researchers invented a new touchscreen material so we never run out

Have you ever imagined your smartphone or tablet without a touchscreen? This could soon be the case if we run out of indium, one of the rarest minerals on Earth.

Indium is used in many high-tech devices such as touch screens, smartphones, solar panels, and smart windows, in the form of indium tin oxide. This compound is optically transparent and electrically conductive — the two crucial features required for touch screens to work.

But there’s a problem: we have no guaranteed long-term supply of indium. It is naturally found only in tiny traces and is therefore impractical to mine directly. Almost all of the world’s indium comes as a byproduct of zinc mining.

Fortunately, we have a potential solution: my colleagues and I have developed a new way to make optically transparent and electrically conductive coatings without indium.

A worsening problem

Because the world’s indium supply is tied to zinc mining, its availability and price will depend on the demand for zinc.

Possible declines in zinc demand — already evident in the car manufacturing industry — along with the ever-increasing usage of smartphones and touch panels — are set to exacerbate the potential shortage of indium in the future.

One option is to try and recycle indium. But recovering it from used devices is expensive because of the tiny amounts involved.

When a crucial material is in short supply, we should look for alternatives. And that’s exactly what my colleagues and I have found.

How does it work?

Our new coating, details of which are published in the journal Solar Energy Materials and Solar Cells, involves plasma technology.

Plasma is like a soup of charged particles in which electrons have been ripped away from their atoms, and is often described as the fourth state of matter, after solid, liquid, and gas. It might sound like an exotic substance, but in fact, it comprises more than 99% of the visible objects in the universe. Our Sun, like most stars, is essentially a giant ball of glowing plasma.

Closer to home, fluorescent light bulbs and neon signs also contain plasma. Our new touchscreen films don’t contain plasma, but their manufacture uses plasma as a way to create new materials that would otherwise be impossible to make.