Scientists have announced the replacement of expensive material used for touch screens

Scientists at the Institute of Materials Science, a division of the University of Pennsylvania, on December 15 introduced new material that can replace indium tin oxide (ITO). The new material does not lag behind the widely used ITO in terms of transparency, conductivity and ease of manufacture, while overtaking it at the cost of the final product.

Indium tin oxide is a transparent conductive material that is used in the manufacture of displays and touch screens. Over the past 60 years, it has been practically indispensable for these purposes, but since the 2000s, due to increased demand, prices for indium have been growing rapidly.

At the moment, the cost of the screen can be up to 40% of the cost of the entire device. As a result, the filling of devices becomes cheaper, and the screen becomes more expensive.

Engineers have long been trying to find an adequate replacement for ITO. This is alumina-zinc oxide, and tin oxide doped with fluorine or antimony, and even graphene . But while the properties of all alternative materials lag behind ITO.

Scientists from Pennsylvania claim that their material is able to replace ITO in the market. They used ultrathin films (10 nm) from the so-called correlating materials. Such materials are composite, they contain both conductive and insulating components. As a result of this, they demonstrate unique properties that are not found in pure conductors and dielectrics.

As scientists explain, in the correlating metals they use, the behavior of electrons is similar to the behavior of liquid molecules, while electrons in ordinary metals behave like a gas.

“We are trying to make metals transparent by changing the effective mass of electrons,” explains team leader researcher Roman Engel-Herbert, assistant professor of materials science. - For this, we take materials in which the electrostatic interaction between electrons greatly exceeds their kinetic energy.

As a result of the effect of strong correlation of electrons, they “feel” each other and behave like a liquid, and not like a gas in which the molecules hardly interact. The electronic “liquid” remains a good conductor, but does not reflect light well, that is, it becomes transparent. ”

To calculate in which materials a similar effect can be achieved, scientists joined forces with material expert Karin Rabe. As a result of the calculations, scientists found that strontium vanadate and calcium vanadate are successfully suited for the role of these materials.

Now a kilogram of iridium is on the market for $ 750. The elements that make up substitute materials are much more common in the earth's crust, and therefore are cheaper. A kilogram of vanadium costs $ 25, and strontium and calcium - even less.

According to scientists, strontium vanadate can theoretically also be used as perovskite - a transparent material with special properties that increase the efficiency of solar panels.

Now, material scientists must submit plans for the industrial production of these materials.