A transparent and electrically-conductive metal has been developed by researchers from Pennsylvania State University. Its applications could range from displays in cheaper smartphones and ‘smart windows’ in houses. The material has been described in a paper published in Nature Materials.
The most popular current display is made of indium tin oxide (ITO). Regarded as relatively expensive, its price has undergone quite some fluctuation, from US$200/kg in 2004 to over $1,000/kg two years later, and right now sold at around $400 or $750/kg – the perfect motivation for scientists to find cheaper alternatives.
The new material that has been concocted by the Pennsylvania State University team is said to match the properties of ITO: optical transparency, and electrical conductivity. They used a new form of material called correlated metal that has a very different molecular structure that allows it to travel like a liquid. Films of correlated metal, each making 10 nanometres in width, were developed.
Engel-Herbert explains their intent in a news release as follows:
“We are trying to make metals transparent by changing the effective mass of their electrons. We are doing this 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 ‘feel’ each other and behave like a liquid rather than a gas of non-interacting particles.”
It becomes extremely transparent when light is shone on it because it becomes less reflective.
The team claims correlated metals such as strontium vanadate and calcium vanadate can be made at a far lower price than ITO.
The next step will be to integrate the new materials into large-scale processing.