U.S. professors develop ultra-thin silver films to become touch screen production materials

According to foreign media reports, a professor at the University of Michigan recently developed an ultra-thin silver film that can replace indium tin oxide (ITO) as the material for smartphone touch screens.

At present, the production of touch screens can not be separated from an important material, that is, indium tin oxide. This transparent conductive material is crucial for the production of various screens such as smartphones and LCD TVs. However, the distribution of indium in the earth's crust is very fragmented and cannot be mined directly from the ground. It is a by-product of refining other metals. Therefore, researchers have been looking for a viable alternative to indium tin oxide for more than a decade.

The price of indium is not extremely expensive (the average price in the free market was about 109 dollars per pound last year), and it is not very rare.

"But its supply is fixed because it has no real main source," said Ioannis Kymissis, associate professor of electrical engineering at Columbia University.

Ioannis Kymissis said that the main reason for seeking alternatives is "to reduce the use of relatively scarce materials." Another reason is that indium tin oxide is not good for flexible and flexible displays because it is very fragile.

Jay Guo, a professor of electrical engineering and computer science at the University of Michigan, recently published a new research report in Advanced Materials magazine, recommending a seven-nanometer thick silver film. Silver is very conductive and is very transparent in this thin case.

However, if you just want to thin silver, the situation does not go well, because it will aggregate into blocks, like islands. Jay Guo solves this problem by mixing silver with copper or aluminum.

"Then this magic will happen," said Jay Guo. "Now we look at this kind of film and it's very smooth."

Jay Guo said that his invention can also help companies create flexible displays because silver is highly ductile and can be placed on flexible plastic devices during manufacturing without heating.

"The market's demand for flexible equipment will increase," he said. "I think this technology can have a very good use."

Ioannis Kymissis, who was not involved in this new study, said that silver is a good material for flexible displays. But he also said that indium tin oxide will not immediately exit the screen production.

"Many people have tried to use alternatives," Kymissis said. "They have either given up or have gone bankrupt." So, in the foreseeable future we will still use indium tin oxide to produce touch screens until the new technology is fully mature.