Nano-thin piezoelectrics advance self-powered electronics

1 min read

According to an Australian research team, a new type of ultra-efficient, nano-thin material could advance self-powered electronics, wearable technologies and even deliver pacemakers powered by heart beats.

Flexible and printable, the piezoelectric material, which can convert mechanical pressure into electrical energy, has been developed by a team of scientists led by RMIT University.

It is said to be 100,000 times thinner than a human hair and 800% more efficient than other piezoelectrics based on similar non-toxic materials.

Researchers say it can be easily fabricated through a cost-effective and commercially scalable method, using liquid metals.

Lead researcher Dr Nasir Mahmood said the material was a major step towards realising the full potential of motion-driven, energy-harvesting devices.

"Until now, the best performing nano-thin piezoelectrics have been based on lead, a toxic material that is not suitable for biomedical use," Mahmood, a Vice-Chancellor's Research Fellow at RMIT, said. "Our new material is based on non-toxic zinc oxide, which is also lightweight and compatible with silicon, making it easy to integrate into current electronics.

"It's so efficient that all you need is a single 1.1 nanometre layer of our material to produce all the energy required for a fully self-powering nanodevice."

The material is produced using a liquid metal printing approach, pioneered at RMIT, in which Zinc oxide is first heated until it becomes liquid. This liquid metal, once exposed to oxygen, forms a nano-thin layer on top - like the skin on heated milk when it cools. The metal is then rolled over a surface, to print off nano-thin sheets of the zinc oxide "skin".

The technique can rapidly produce large-scale sheets of the material and is compatible with any manufacturing process, including roll-to-roll (R2R) processing.

The material's potential biomedical applications include internal biosensors and self-powering biotechnologies, such as devices that convert blood pressure into a power source for pacemakers.

The nano-thin piezoelectrics could also be used in the development of smart oscillation sensors to detect faults in infrastructure like buildings and bridges, especially in earthquake-prone regions.

Image credit: Image of pacemaker by Lucien Monfils, licensed under the Creative Commons Attribution-Share Alike 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license