Capacitive touch panels – the technology that enables your phone or tablet to respond to your touch – are quite expensive. That’s because more than 90% of touchscreens are made with indium tin oxide (ITO). While the cost of circuits, chips, and processors has decreased over time, ITO prices have been increasing – so much so, that the touchscreen makes up about 40% of a device’s manufacturing cost. The cost of ITO has been a major hurdle in the development of bigger, better touchscreen devices. There just hasn’t been an effective alternative – until now.
Researchers at Pennsylvania State University led by engineer Roman Engel-Herbert have developed a replacement for ITO that matches its optical transparency, electrical conductivity, and efficiency of manufacture. In their research, they developed and studied 10-namometer-thick films of strontium vanadate and calcium vanadate – which belong to an unusual class of materials called “correlated metals.” In conventional metals, such as gold and silver, electrons flow like a gas. But in correlated metals they move like a liquid. According to Engel-Herbert and his team, this electron flow produces high optical transparency along with high metal-like conductivity. In other words, it functions just as well as ITO in touchscreens.
Additionally, vanadium and strontium both cost only a fraction of ITO. While ITO can cost between $400-750 per kilogram (depending on market factors), vanadium averages about $25 per kilogram, and strontium even less so. Once large scale manufacturing for the materials is developed, it won’t be long before you start seeing transparent metal in smartphones and other devices.
