Researchers at Pennsylvania State University have developed a transparent and electrically conductive material that could make large screen displays, smart windows, touch screens and solar cells more affordable and efficient. The material has the potential to replace indium tin oxide (ITO), the transparent conductor that is currently used for more than 90% of the display market but is expensive, scarce and brittle.
Along with display technologies, the researchers will investigate the new materials with a type of solar cell that uses organic perovskite materials. The team has reported a design strategy using 10 nm-thick films of an unusual class of materials called correlated metals. In most conventional metals, such as copper, gold, aluminum or silver, electrons flow like a gas. In correlated metals, such as strontium vanadate (a perovskite material) and calcium vanadate, they move more like a liquid. The electron flow produces high optical transparency along with high metal-like conductivity, the researchers said.
The scientists are trying to make metals transparent by changing the effective mass of their electrons, by choosing materials in which the electrostatic interaction between negatively charged electrons is very large compared to their kinetic energy. As a result of this strong electron correlation effect, electrons 'sense' each other and behave like a liquid rather than a gas of noninteracting particles. This electron liquid is still highly conductive, but when one shines a light on it, it becomes less reflective, thus much more transparent. The correlated metals demonstrated excellent performance when benchmarked against ITO, the researchers said.
The next challenge will be to find a method of implementing these new materials into a large-scale manufacturing process. The researchers claim that they see no reason that strontium vanadate could not replace ITO in the same equipment currently used in industry.