Ultralow-power devices could harvest their own energy

An international research team has created a way for ultralow-power printed electronics to recharge from ambient light or radiofrequency noise, paving the way for low-cost devices that could be seamlessly embedded in everyday objects and environments. Their work has been described in the journal ACS Nano.

Electronics that consume tiny amounts of power are key for the development of the Internet of Things. Many emerging technologies, from wearables to healthcare devices to smart homes and smart cities, need cost-effective transistors and electronic circuits that can function with minimal energy use.

Printed electronics are a simple and inexpensive way to manufacture electronics that could pave the way for low-cost electronic devices on unconventional substrates — such as clothes, plastic wrap or paper — and provide everyday objects with ‘intelligence’. However, these devices need to operate with low energy and power consumption to be useful for real-world applications — a challenge that has been difficult to overcome without overly complex solutions, which are not ideal for commercial production.

Researchers from Soochow University, working with collaborators from the Chinese Academy of Sciences, ShanghaiTech University, the University of Cambridge and the King Abdullah University of Science and Technology (KAUST), have now developed an approach for printed electronics that could be used to make low-cost devices that recharge out of thin air. Even the ambient radio signals that surround us would be enough to power them.

The team’s technology delivers high-performance electronic circuits based on thin-film transistors which are ‘ambipolar’ as they use only one semiconducting material to transport both negative and positive electric charges in their channels, in a region of operation called ‘deep subthreshold’ — a phrase that essentially means that the transistors are operated in a region that is conventionally regarded as their ‘off’ state. The researchers used printed carbon nanotubes — ultrathin cylinders of carbon — as an ambipolar semiconductor to achieve the result.

The team coined the phrase ‘deep-subthreshold ambipolar’ to refer to their ultralow operating voltages and power consumption levels. If electronic circuits made of these devices were to be powered by a standard AA battery, the researchers say it would be possible that they could run for millions of years uninterrupted.

“Thanks to deep-subthreshold ambipolar approach, we created printed electronics that meet the power and voltage requirements of real-world applications and opened up opportunities for remote sensing and ‘place-and-forget’ devices that can operate without batteries for their entire lifetime,” said co-author Luigi Occhipinti from the University of Cambridge. “Crucially, our ultralow-power printed electronics are simple and cost-effective to manufacture and overcome longstanding hurdles in the field.”

“Our approach to printed electronics could be scaled up to make inexpensive, battery-less devices that could harvest energy from the environment, such as sunlight or omnipresent ambient electromagnetic waves, like those created by our mobile phones and Wi-Fi stations,” added co-lead author Professor Vincenzo Pecunia from Soochow University. The work thus paves the way for a new generation of self-powered electronics for biomedical applications, smart homes, infrastructure monitoring and the Internet of Things.

Image caption: Artist’s impression of a hybrid nanodielectric-based printed-CNT transistor. Image credit: Luis Portilla.

This is a modified version of a news item published by the University of Cambridge under CC BY 4.0.

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