To produce the new conductive film, the RMIT University team used indium tin oxide, which is commonly used in mobile phone touch screens, as the starting material. Although the material is highly conductive, it is also very brittle. With the help of a special liquid metal printing process they were able to eliminate this disadvantage.
During the process, an indium-tin alloy is heated to 200 °C and thus liquefied. The liquid material is then spread over a surface and rolled into nano-thin plates. These two-dimensional nanosheets have the same chemical composition as ordinary indium tin oxide, but have a different crystal structure that gives them new mechanical and optical properties.
The result: according to the scientists, the new material is not only extremely flexible, but also more transparent than ordinary indium tin oxide. While the latter absorbs around 5 to 10 percent of light, the new material absorbs only 0.7 percent.
The team is convinced of the new technology: "It is a groundbreaking approach that solves a challenge that was considered insoluble," says lead researcher Dr. Torben Daeneke. " There is no other way to produce this completely flexible, conductive and transparent material than our new liquid metal method."
So far, the team has used the new material to develop a working touch screen prototype. However, other applications are also conceivable, for example in optoelectronic applications such as LEDs and touch displays, in solar cells and smart windows.
Researchers from UNSW Sydney, Monash University and the ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET) are involved in the research. The results will be published in the journal Nature Electronics.