Jan 19, 2021 |
Nano-thin piezoelectrics advance self-powered electronics
(Nanowerk News) A new type of ultra-efficient, nano-thin material could advance self-powered electronics, wearable technologies and even deliver pacemakers powered by heart beats.
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The flexible and printable piezoelectric material, which can convert mechanical pressure into electrical energy, has been developed by an Australian research team led by RMIT University.
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It is 100,000 times thinner than a human hair and 800% more efficient than other piezoelectrics based on similar non-toxic materials.
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Importantly, researchers say it can be easily fabricated through a cost-effective and commercially scalable method, using liquid metals.
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Lead researcher Dr Nasir Mahmood said the material, detailed in a new Materials Today study ("Maximum piezoelectricity in a few unit-cell thick planar ZnO – A liquid metal-based synthesis approach"), was a major step towards realising the full potential of motion-driven, energy-harvesting devices.
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"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.
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"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.
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"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."
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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.
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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.
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Examples of energy-harvesting technologies that could be delivered by integrating the new material include smart running shoes for charging mobile phones and smart footpaths that harness energy from footsteps. |
Flexible nanogenerator: how the material is made
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The new material is produced using a liquid metal printing approach, pioneered at RMIT.
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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.
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The metal is then rolled over a surface, to print off nano-thin sheets of the zinc oxide "skin".
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The innovative technique can rapidly produce large-scale sheets of the material and is compatible with any manufacturing process, including roll-to-roll (R2R) processing.
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The researchers are now working on ultrasonic detectors for use in defence and infrastructure monitoring, as well as investigating the development of nanogenerators for harvesting mechanical energy.
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"We're keen to explore commercial collaboration opportunities and work with relevant industries to bring future power-generating nanodevices to market," Mahmood said.
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