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New green materials could power smart devices using ambient light

Anonymous — Tue, 17 Nov 2020 02:14:38 +0000

We are increasingly using more smart devices like smartphones, smart speakers, and wearable health and wellness sensors in our homes, offices, and public buildings. However, the batteries they use can deplete quickly and contain toxic and rare environmentally damaging chemicals, so researchers are looking for better ways to power the devices.

One way to power them is by converting indoor light from ordinary bulbs into energy, in a similar way to how solar panels harvest energy from sunlight, known as solar photovoltaics. However, due to the different properties of the light sources, the materials used for solar panels are not suitable for harvesting indoor light.

Now, researchers from the ̽��ֱ�� of Cambridge, Imperial College London and Soochow ̽��ֱ�� in China have discovered that new green materials currently being developed for next-generation solar panels could be useful for indoor light harvesting. They report their findings in Advanced Energy Materials.

“By efficiently absorbing the light coming from lamps commonly found in homes and buildings, the materials can turn light into electricity with an efficiency already in the range of commercial technologies,” said co-author Dr Robert Hoye from Imperial College London. “We have also already identified several possible improvements, which would allow these materials to surpass the performance of current indoor photovoltaic technologies in the near future.”

̽��ֱ��team investigated perovskite-inspired materials, which were created to circumvent problems with materials called perovskites, which were developed for next-generation solar cells. Although perovskites are cheaper to make than traditional silicon-based solar panels and deliver similar efficiency, perovskites contain toxic lead substances. This drove the development of perovskite-inspired materials, which are instead based on safer elements like bismuth and antimony.

Despite being more environmentally friendly, these perovskite-inspired materials are not as efficient at absorbing sunlight. However, the team found that the materials are much more effective at absorbing indoor light, with efficiencies that are promising for commercial applications. Crucially, the researchers demonstrated that the power provided by these materials under indoor illumination is already sufficient to operate electronic circuits.

" ̽��ֱ��Internet of Things is critical for many areas, such as improved healthcare, energy conservation, transportation or control of smart buildings," said co-authro Professor Judith Driscoll from Cambridge's Department of Materials Science and Metallurgy. "New generations of wireless connected IoT devices function with low-power electronics ideally suited to operate with energy-scavenging devices."

"Access to sustainable and efficient indoor photovoltaic energy harvesters offers unique opportunities to operate these IoT devices by collecting ambient energy from daily environments extending their operating lifetime and reducing maintenance costs," said co-author Dr Luigi Occhipinti from Cambridge's Department of Engineering.

“Our discovery opens up a whole new direction in the search for green, easy-to-make materials to sustainably power our smart devices,” said co-author Professor Vincenzo Pecunia from Soochow ̽��ֱ��.

In addition to their eco-friendly nature, these materials could potentially be processed onto unconventional substrates such as plastics and fabric, which are incompatible with conventional technologies. Therefore, lead-free perovskite-inspired materials could soon enable battery-free devices for wearables, healthcare monitoring, smart homes, and smart cities.

This research was funded by EPSRC and National Natural Science Foundation of China.

Reference:
Yueheng Peng et al. ‘Lead‐Free Perovskite‐Inspired Absorbers for Indoor Photovoltaics.’ Advanced Energy Material (2020). DOI: 10.1002/aenm.202002761

Originally published on the Imperial College London website.

A bold response to the world’s greatest challenge

̽��ֱ�� ̽��ֱ�� of Cambridge is building on its existing research and launching an ambitious new environment and climate change initiative. Cambridge Zero is not just about developing greener technologies. It will harness the full power of the ̽��ֱ��’s research and policy expertise, developing solutions that work for our lives, our society and our biosphere.

Researchers have developed environmentally friendly materials that could harvest enough energy from indoor light to power wireless smart devices.

Luis Tosta on Unsplash

Light bulbs

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Easy-to-make, ultra-low-power electronics could charge out of thin air

Anonymous — Tue, 13 Oct 2020 11:25:02 +0000

Electronics that consume tiny amounts of power are key for the development of the Internet of Things, in which everyday objects are connected to the internet. 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. Although printing techniques have advanced considerably, power consumption has remained a challenge – the different solutions available were too complex for commercial production.

Now, researchers from the ̽��ֱ�� of Cambridge, working with collaborators from China and Saudi Arabia, have 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. Their results are published in the journal ACS Nano.

Since the commercial batteries which power many devices have limited lifetimes and negative environmental impacts, researchers are developing electronics that can operate autonomously with ultra-low levels of energy.

̽��ֱ��technology developed by the researchers 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. ̽��ֱ��team coined the phrase ‘deep-subthreshold ambipolar’ to refer to unprecedented ultra-low 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.

̽��ֱ��team, which included researchers from Soochow ̽��ֱ��, the Chinese Academy of Sciences, ShanghaiTech ̽��ֱ��, and King Abdullah ̽��ֱ�� of Science and Technology (KAUST), used printed carbon nanotubes – ultra-thin cylinders of carbon – as an ambipolar semiconductor to achieve the result.

“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-lead author Luigi Occhipinti from Cambridge’s Department of Engineering. “Crucially, our ultra-low-power printed electronics are simple and cost-effective to manufacture and overcome long-standing 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 wifi stations,” said co-lead author Professor Vincenzo Pecunia from Soochow ̽��ֱ��. Pecunia is a former PhD student and postdoctoral researcher at Cambridge’s Cavendish Laboratory.

̽��ֱ��work paves the way for a new generation of self-powered electronics for biomedical applications, smart homes, infrastructure monitoring, and the exponentially-growing Internet of Things device ecosystem.

̽��ֱ��research was funded in part by the Engineering and Physical Sciences Research Council (EPSRC).

Reference:
L. Portilla et al. ‘Ambipolar Deep-Subthreshold Printed-Carbon-Nanotube Transistors for Ultralow-Voltage and Ultralow-Power Electronics.’ ACS Nano (2020). DOI: 10.1021/acsnano.0c06619

Researchers have developed a new approach to printed electronics that allows ultra-low-power electronic devices which could recharge from ambient light or radiofrequency noise. ̽��ֱ��approach paves the way for low-cost printed electronics that could be seamlessly embedded in everyday objects and environments.

Luis Portilla

Artist's impression of a hybrid-nanodielectric-based printed-CNT transistor

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