A team led by a researcher from the University of Sydney has developed a low-cost, sustainable, and readily available technology that could see the phase-out of rare earth metal indium, which is predicted to run out within a decade.
Indium is a rare chemical element widely used in devices such as smartphones and computers, windscreen glass and self-dimming windows.
Although small amounts are used to manufacture smart device screens, indium is expensive as it naturally occurs only in small deposits and is therefore difficult to source.
Led by Dr Behnam Akhavan, ARC DECRA Fellow of the School of Biomedical Engineering, School of Physics and Sydney Nanoscience Hub, the research team developed an innovative, indium-free plasma coating technology that can dim the screens of electronic devices, anti-reflection automobile mirrors, and smart architectural windows at a fraction of the cost of current technology.
Dr Akhavan said the plasma-generated material is composed of tungsten oxide and silver and can be applied to coat almost any solid surface, including flexible plastics.
“When you change the transparency of a wearable electronic or a smart window, an electrochromic device is doing the work,” he explained.
“Until now, these devices have typically relied on materials like rare indium to do the job. What we have created is a manufacturer’s dream: a technology that removes the need for indium and instead uses a plasma-engineered, three-layered structure that is much cheaper to produce.”
The plasma coatings – which are transparent and electrically conductive – are made up of a layer of silver that is approximately 10,000 times thinner than the width of human hair, placed in between two nano-thin layers of tungsten oxide decorated with silver nanoparticles.
“These plasma-fabricated coatings can then be applied to electronic papers, smart phones and glass windows and can be dimmed with the application of a small electrical current,” Dr Akhavan concluded.