Tag Archives: electricity

Carbon nanotubes can scavenge energy from environment to generate electricity

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A June 7, 2021 news item on phys.org announces research into a new method for generating electricity (Note: A link has been removed),

MIT [Massachusetts Institute of Technology] engineers have discovered a new way of generating electricity using tiny carbon particles that can create a current simply by interacting with liquid surrounding them.

The liquid, an organic solvent, draws electrons out of the particles, generating a current that could be used to drive chemical reactions or to power micro- or nanoscale robots, the researchers say.

“This mechanism is new, and this way of generating energy is completely new,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT. “This technology is intriguing because all you have to do is flow a solvent through a bed of these particles. This allows you to do electrochemistry, but with no wires.”

A June 7, 2021 MIT news release (also on EurekAlert), which generated the news item, delves further into the research,

In a new study describing this phenomenon, the researchers showed that they could use this electric current to drive a reaction known as alcohol oxidation — an organic chemical reaction that is important in the chemical industry.

Strano is the senior author of the paper, which appears today [June 7, 2021] in Nature Communications. The lead authors of the study are MIT graduate student Albert Tianxiang Liu and former MIT researcher Yuichiro Kunai. Other authors include former graduate student Anton Cottrill, postdocs Amir Kaplan and Hyunah Kim, graduate student Ge Zhang, and recent MIT graduates Rafid Mollah and Yannick Eatmon.

Unique properties

The new discovery grew out of Strano’s research on carbon nanotubes — hollow tubes made of a lattice of carbon atoms, which have unique electrical properties. In 2010, Strano demonstrated, for the first time, that carbon nanotubes can generate “thermopower waves.” When a carbon nanotube is coated with layer of fuel, moving pulses of heat, or thermopower waves, travel along the tube, creating an electrical current.

That work led Strano and his students to uncover a related feature of carbon nanotubes. They found that when part of a nanotube is coated with a Teflon-like polymer, it creates an asymmetry that makes it possible for electrons to flow from the coated to the uncoated part of the tube, generating an electrical current. Those electrons can be drawn out by submerging the particles in a solvent that is hungry for electrons.

To harness this special capability, the researchers created electricity-generating particles by grinding up carbon nanotubes and forming them into a sheet of paper-like material. One side of each sheet was coated with a Teflon-like polymer, and the researchers then cut out small particles, which can be any shape or size. For this study, they made particles that were 250 microns by 250 microns.

When these particles are submerged in an organic solvent such as acetonitrile, the solvent adheres to the uncoated surface of the particles and begins pulling electrons out of them.

“The solvent takes electrons away, and the system tries to equilibrate by moving electrons,” Strano says. “There’s no sophisticated battery chemistry inside. It’s just a particle and you put it into solvent and it starts generating an electric field.”

Particle power

The current version of the particles can generate about 0.7 volts of electricity per particle. In this study, the researchers also showed that they can form arrays of hundreds of particles in a small test tube. This “packed bed” reactor generates enough energy to power a chemical reaction called an alcohol oxidation, in which an alcohol is converted to an aldehyde or a ketone. Usually, this reaction is not performed using electrochemistry because it would require too much external current.

“Because the packed bed reactor is compact, it has more flexibility in terms of applications than a large electrochemical reactor,” Zhang says. “The particles can be made very small, and they don’t require any external wires in order to drive the electrochemical reaction.”

In future work, Strano hopes to use this kind of energy generation to build polymers using only carbon dioxide as a starting material. In a related project, he has already created polymers that can regenerate themselves using carbon dioxide as a building material, in a process powered by solar energy. This work is inspired by carbon fixation, the set of chemical reactions that plants use to build sugars from carbon dioxide, using energy from the sun.

In the longer term, this approach could also be used to power micro- or nanoscale robots. Strano’s lab has already begun building robots at that scale, which could one day be used as diagnostic or environmental sensors. The idea of being able to scavenge energy from the environment to power these kinds of robots is appealing, he says.

“It means you don’t have to put the energy storage on board,” he says. “What we like about this mechanism is that you can take the energy, at least in part, from the environment.”

Here’s a link to and a citation for the paper,

Solvent-induced electrochemistry at an electrically asymmetric carbon Janus particle by Albert Tianxiang Liu, Yuichiro Kunai, Anton L. Cottrill, Amir Kaplan, Ge Zhang, Hyunah Kim, Rafid S. Mollah, Yannick L. Eatmon & Michael S. Strano. Nature Communications volume 12, Article number: 3415 (2021) DOI: https://doi.org/10.1038/s41467-021-23038-7Published 07 June 2021

This paper is open access.

Better performing solar cells with newly discovered property of pristine graphene

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Light-harvesting devices—I like that better than solar cells or the like but I think that the term serves as a category rather than a name/label for a specific device. Enough musing. A December 17, 2018 news item on Nanowerk describes the latest about graphene and light-harvesting devices (Note: A link has been removed,

An international research team, co-led by a physicist at the University of California, Riverside, has discovered a new mechanism for ultra-efficient charge and energy flow in graphene, opening up opportunities for developing new types of light-harvesting devices.

The researchers fabricated pristine graphene — graphene with no impurities — into different geometric shapes, connecting narrow ribbons and crosses to wide open rectangular regions. They found that when light illuminated constricted areas, such as the region where a narrow ribbon connected two wide regions, they detected a large light-induced current, or photocurrent.

The finding that pristine graphene can very efficiently convert light into electricity could lead to the development of efficient and ultrafast photodetectors — and potentially more efficient solar panels.

A December 14, 2018 University of California at Riverside (UCR) news release by Iqbal Pittalwala (also on EurekAlert but published Dec. 17, 2018), which originated the news item,gives a brief description of graphene while adding context for this research,


Graphene, a 1-atom thick sheet of carbon atoms arranged in a hexagonal lattice, has many desirable material properties, such as high current-carrying capacity and thermal conductivity. In principle, graphene can absorb light at any frequency, making it ideal material for infrared and other types of photodetection, with wide applications in bio-sensing, imaging, and night vision.

In most solar energy harvesting devices, a photocurrent arises only in the presence of a junction between two dissimilar materials, such as “p-n” junctions, the boundary between two types of semiconductor materials. The electrical current is generated in the junction region and moves through the distinct regions of the two materials.

“But in graphene, everything changes,” said Nathaniel Gabor, an associate professor of physics at UCR, who co-led the research project. “We found that photocurrents may arise in pristine graphene under a special condition in which the entire sheet of graphene is completely free of excess electronic charge. Generating the photocurrent requires no special junctions and can instead be controlled, surprisingly, by simply cutting and shaping the graphene sheet into unusual configurations, from ladder-like linear arrays of contacts, to narrowly constricted rectangles, to tapered and terraced edges.”

Pristine graphene is completely charge neutral, meaning there is no excess electronic charge in the material. When wired into a device, however, an electronic charge can be introduced by applying a voltage to a nearby metal. This voltage can induce positive charge, negative charge, or perfectly balance negative and positive charges so the graphene sheet is perfectly charge neutral.

“The light-harvesting device we fabricated is only as thick as a single atom,” Gabor said. “We could use it to engineer devices that are semi-transparent. These could be embedded in unusual environments, such as windows, or they could be combined with other more conventional light-harvesting devices to harvest excess energy that is usually not absorbed. Depending on how the edges are cut to shape, the device can give extraordinarily different signals.”

The research team reports this first observation of an entirely new physical mechanism — a photocurrent generated in charge-neutral graphene with no need for p-n junctions — in Nature Nanotechnology today [Dec. 17, 2018].

Previous work by the Gabor lab showed a photocurrent in graphene results from highly excited “hot” charge carriers. When light hits graphene, high-energy electrons relax to form a population of many relatively cooler electrons, Gabor explained, which are subsequently collected as current. Even though graphene is not a semiconductor, this light-induced hot electron population can be used to generate very large currents.

“All of this behavior is due to graphene’s unique electronic structure,” he said. “In this ‘wonder material,’ light energy is efficiently converted into electronic energy, which can subsequently be transported within the material over remarkably long distances.”

He explained that, about a decade ago, pristine graphene was predicted to exhibit very unusual electronic behavior: electrons should behave like a liquid, allowing energy to be transferred through the electronic medium rather than by moving charges around physically.
“But despite this prediction, no photocurrent measurements had been done on pristine graphene devices — until now,” he said.

The new work on pristine graphene shows electronic energy travels great distances in the absence of excess electronic charge.

The research team has found evidence that the new mechanism results in a greatly enhanced photoresponse in the infrared regime with an ultrafast operation speed.
“We plan to further study this effect in a broad range of infrared and other frequencies, and measure its response speed,” said first author Qiong Ma, a postdoctoral associate in physics at the Massachusetts Institute of Technology, or MIT.

The researchers have provided an image illustrating their work,

Caption: Shining light on graphene: Although graphene has been studied vigorously for more than a decade, new measurements on high-performance graphene devices have revealed yet another unusual property. In ultra-clean graphene sheets, energy can flow over great distances, giving rise to an unprecedented response to light. Credit: Max Grossnickle and QMO Labs, UC Riverside.

Here’s a link to and a citation for the paper,

Giant intrinsic photoresponse in pristine graphene by Qiong Ma, Chun Hung Lui, Justin C. W. Song, Yuxuan Lin, Jian Feng Kong, Yuan Cao, Thao H. Dinh, Nityan L. Nair, Wenjing Fang, Kenji Watanabe, Takashi Taniguchi, Su-Yang Xu, Jing Kong, Tomás Palacios, Nuh Gedik, Nathaniel M. Gabor, & Pablo Jarillo-Herrero. Nature Nanotechnology (2018) Published 17 December 2018 DOI: https://doi.org/10.1038/s41565-018-0323-8

This paper is behind a paywall.

Bandage with nanogenerator promotes healing

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This bandage not only heals wounds (on rats) much faster; it’s cheap, according to a November 29, 2018 news item on Nanowerk,

A new, low-cost wound dressing developed by University of Wisconsin-Madison engineers could dramatically speed up healing in a surprising way.

The method leverages energy generated from a patient’s own body motions to apply gentle electrical pulses at the site of an injury.

In rodent tests, the dressings reduced healing times to a mere three days compared to nearly two weeks for the normal healing process.

“We were surprised to see such a fast recovery rate,” says Xudong Wang, a professor of materials science and engineering at UW-Madison. “We suspected that the devices would produce some effect, but the magnitude was much more than we expected.”

A November 29, 2018 University of Wisconsin-Madison news release (also on EurekAlert) by Sam Million-Weaver, which originated the news item, expands on the theme,

Researchers have known for several decades that electricity can be beneficial for skin healing, but most electrotherapy units in use today require bulky electrical equipment and complicated wiring to deliver powerful jolts of electricity.

“Acute and chronic wounds represent a substantial burden in healthcare worldwide,” says collaborator Angela Gibson, professor of surgery at UW-Madison and a burn surgeon and director of wound healing services at UW Health. “The use of electrical stimulation in wound healing is uncommon.”

In contrast with existing methods, the new dressing is much more straightforward.

“Our device is as convenient as a bandage you put on your skin,” says Wang.

The new dressings consist of small electrodes for the injury site that are linked to a band holding energy-harvesting units called nanogenerators, which are looped around a wearer’s torso. The natural expansion and contraction of the wearer’s ribcage during breathing powers the nanogenerators, which deliver low-intensity electric pulses.

“The nature of these electrical pulses is similar to the way the body generates an internal electric field,” says Wang.

And, those low-power pulses won’t harm healthy tissue like traditional, high-power electrotherapy devices might.

In fact, the researchers showed that exposing cells to high-energy electrical pulses caused them to produce almost five times more reactive oxygen species — major risk factors for cancer and cellular aging — than did cells that were exposed to the nanogenerators.

Also a boon to healing: They determined that the low-power pulses boosted viability for a type of skin cell called fibroblasts, and exposure to the nanogenerator’s pulses encouraged fibroblasts to line up (a crucial step in wound healing) and produce more biochemical substances that promote tissue growth.

“These findings are very exciting,” says collaborator Weibo Cai, a professor of radiology at UW-Madison. “The detailed mechanisms will still need to be elucidated in future work.”

In that vein, the researchers aim to tease out precisely how the gentle pulses aid in healing. The scientists also plan to test the devices on pig skin, which closely mimics human tissue.

And, they are working to give the nanogenerators additional capabilities–tweaking their structure to allow for energy harvesting from small imperceptible twitches in the skin or the thrumming pulse of a heartbeat.

“The impressive results in this study represent an exciting new spin on electrical stimulation for many different wound types, given the simplicity of the design,” says Gibson, who will collaborate with the team to confirm the reproducibility of these results in human skin models.

If the team is successful, the devices could help solve a major challenge for modern medicine.

“We think our nanogenerator could be the most effective electrical stimulation approach for many therapeutic purposes,” says Wang.

And because the nanogenerators consist of relatively common materials, price won’t be an issue.

“I don’t think the cost will be much more than a regular bandage,” says Wang. “The device in itself is very simple and convenient to fabricate.”

Here’s a link to and a citation for the paper,

Effective Wound Healing Enabled by Discrete Alternative Electric Fields from Wearable Nanogenerators by Yin Long, Hao Wei, Jun Li, Guang Yao, Bo Yu, Dalong Ni, Angela LF Gibson, Xiaoli Lan, Yadong Jiang, Weibo Cai, and Xudong Wang. ACS Nano, Article ASAP DOI: 10.1021/acsnano.8b07038 Publication Date (Web): November 29, 2018

Copyright © 2018 American Chemical Society

This paper is open access.

I assume it will be a while before there are human clinical trials.

Bendable phones that are partially organic

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It’s been about nine  or 10 years since I first heard about bendable phones (my September 29, 2010 posting). The concept keeps popping up from time to time (my April 25, 2017 posting) and this time, we have Australian scientists to thank for this latest work described in an October 5, 2018 news item on Nanowerk (Note: A link has been removed),

Engineers at ANU [Australian National University] have invented a semiconductor with organic and inorganic materials that can convert electricity into light very efficiently, and it is thin and flexible enough to help make devices such as mobile phones bendable (Advanced Materials, “Efficient and Layer-Dependent Exciton Pumping across Atomically Thin Organic–Inorganic Type-I Heterostructures”).

The invention also opens the door to a new generation of high-performance electronic devices made with organic materials that will be biodegradable or that can be easily recycled, promising to help substantially reduce e-waste.

An October 5, 2018 ANU press release (also on EurekAlert but published October 4, 2018) expands on the theme,

The huge volumes of e-waste generated by discarded electronic devices around the world is causing irreversible damage to the environment. Australia produces 200,000 tonnes of e-waste every year – only four per cent of this waste is recycled.

The organic component has the thickness of just one atom – made from just carbon and hydrogen – and forms part of the semiconductor that the ANU team developed. The inorganic component has the thickness of around two atoms. The hybrid structure can convert electricity into light efficiently for displays on mobile phones, televisions and other electronic devices.

Lead senior researcher Associate Professor Larry Lu said the invention was a major breakthrough in the field.

“For the first time, we have developed an ultra-thin electronics component with excellent semiconducting properties that is an organic-inorganic hybrid structure and thin and flexible enough for future technologies, such as bendable mobile phones and display screens,” said Associate Professor Lu from the ANU Research School of Engineering.

PhD researcher Ankur Sharma, who recently won the ANU 3-Minute Thesis competition, said experiments demonstrated the performance of their semiconductor would be much more efficient than conventional semiconductors made with inorganic materials such as silicon.

“We have the potential with this semiconductor to make mobile phones as powerful as today’s supercomputers,” said Mr Sharma from the ANU Research School of Engineering.

“The light emission from our semiconducting structure is very sharp, so it can be used for high-resolution displays and, since the materials are ultra-thin, they have the flexibility to be made into bendable screens and mobile phones in the near future.”

The team grew the organic semiconductor component molecule by molecule, in a similar way to 3D printing. The process is called chemical vapour deposition.

“We characterised the opto-electronic and electrical properties of our invention to confirm the tremendous potential of it to be used as a future semiconductor component,” Associate Professor Lu said.

“We are working on growing our semiconductor component on a large scale, so it can be commercialised in collaboration with prospective industry partners.”

Here’s a link to and a citation for the paper,

Efficient and Layer‐Dependent Exciton Pumping across Atomically Thin Organic–Inorganic Type‐I Heterostructures by Linglong Zhang, Ankur Sharma, Yi Zhu, Yuhan Zhang, Bowen Wang, Miheng Dong, Hieu T. Nguyen, Zhu Wang, Bo Wen, Yujie Cao, Boqing Liu, Xueqian Sun, Jiong Yang, Ziyuan Li. Advanced Materials Volume30, Issue 40 1803986 (October 4, 2018) DOI:https://doi.org/10.1002/adma.201803986 First published [onliine]: 30 August 2018

This paper is behind a paywall.

Tracks of my tears could power smartphone?

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So far the researchers aren’t trying to power anything with tears but they have discovered that tears could be used to generate electricity (from an Oct. 2, 2017 news item on phys.org),

A team of Irish scientists has discovered that applying pressure to a protein found in egg whites and tears can generate electricity. The researchers from the Bernal Institute, University of Limerick (UL), Ireland, observed that crystals of lysozyme, a model protein that is abundant in egg whites of birds as well as in the tears, saliva and milk of mammals can generate electricity when pressed. Their report is published today (October 2) in the journal, Applied Physics Letters.

An Oct. 2, 2017 University of Limerick press release (also on EurekAlert), which originated the news item, offers additional detail,

The ability to generate electricity by applying pressure, known as direct piezoelectricity, is a property of materials such as quartz that can convert mechanical energy into electrical energy and vice versa. Such materials are used in a variety of applications ranging from resonators and vibrators in mobile phones to deep ocean sonars and ultrasound imaging. Bone, tendon and wood are long known to possess piezoelectricity.

“While piezoelectricity is used all around us, the capacity to generate electricity from this particular protein had not been explored. The extent of the piezoelectricity in lysozyme crystals is significant. It is of the same order of magnitude found in quartz. However, because it is a biological material, it is non toxic so it could have many innovative applications such as electroactive anti-microbial coatings for medical implants,” explained Aimee Stapleton, the lead author and an Irish Research Council EMBARK Postgraduate Fellow in the Department of Physics and Bernal Institute of UL.

Crystals of lysozyme are easy to make from natural sources. “The high precision structure of lysozyme crystals has been known since 1965,” said structural biologist at UL and co-author Professor Tewfik Soulimane.
“In fact, it is the second protein structure and the first enzyme structure that was ever solved,” he added, “but we are the first to use these crystals to show the evidence of piezoelectricity”.

According to team leader Professor Tofail Syed of UL’s Department of Physics, “Crystals are the gold-standard for measuring piezoelectricity in non-biological materials. Our team has shown that the same approach can be taken in understanding this effect in biology. This is a new approach as scientists so far have tried to understand piezoelectricity in biology using complex hierarchical structures such as tissues, cells or polypeptides rather than investigating simpler fundamental building blocks”.

The discovery may have wide reaching applications and could lead to further research in the area of energy harvesting and flexible electronics for biomedical devices. Future applications of the discovery may include controlling the release of drugs in the body by using lysozyme as a physiologically mediated pump that scavenges energy from its surroundings. Being naturally biocompatible and piezoelectric, lysozyme may present an alternative to conventional piezoelectric energy harvesters, many of which contain toxic elements such as lead.

Professor Luuk van der Wielen, Director of Bernal Institute and Bernal Professor of Biosystems Engineering and Design expressed his delight at this breakthrough by UL scientists.

“The €109-million Bernal Institute has the ambition to impact the world on the basis of top science in an increasingly international context. The impact of this discovery in the field of biological piezoelectricity will be huge and Bernal scientists are leading from the front the progress in this field,” he said.

Here’s a link to and a citation for the paper,

The direct piezoelectric effect in the globular protein lysozyme featured by A. Stapleton, M. R. Noor, J. Sweeney, V. Casey, A. L. Kholkin, C. Silien, A. A. Gandhi, T. Soulimane, and S. A. M. Tofail. Appl. Phys. Lett. 111, 142902 (2017); doi: http://dx.doi.org/10.1063/1.4997446

This paper is open access.

As for Tracks of My Tears,

Vampire nanogenerators: 2017

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Researchers have been working on ways to harvest energy from bloodstreams. I last wrote about this type of research in an April 3, 2009 posting about ‘vampire batteries ‘(for use in pacemakers). The latest work according to a Sept. 8, 2017 news item on Nanowerk comes from China,

Men build dams and huge turbines to turn the energy of waterfalls and tides into electricity. To produce hydropower on a much smaller scale, Chinese scientists have now developed a lightweight power generator based on carbon nanotube fibers suitable to convert even the energy of flowing blood in blood vessels into electricity. They describe their innovation in the journal Angewandte Chemie (“A One-Dimensional Fluidic Nanogenerator with a High Power Conversion Efficiency”)

A Sept. 8, 2017 Wiley Publishing news release (also on EurekAlert), which originated the news item, expands on the theme,

For thousands of years, people have used the energy of flowing or falling water for their purposes, first to power mechanical engines such as watermills, then to generate electricity by exploiting height differences in the landscape or sea tides. Using naturally flowing water as a sustainable power source has the advantage that there are (almost) no dependencies on weather or daylight. Even flexible, minute power generators that make use of the flow of biological fluids are conceivable. How such a system could work is explained by a research team from Fudan University in Shanghai, China. Huisheng Peng and his co-workers have developed a fiber with a thickness of less than a millimeter that generates electrical power when surrounded by flowing saline solution—in a thin tube or even in a blood vessel.

The construction principle of the fiber is quite simple. An ordered array of carbon nanotubes was continuously wrapped around a polymeric core. Carbon nanotubes are well known to be electroactive and mechanically stable; they can be spun and aligned in sheets. In the as-prepared electroactive threads, the carbon nanotube sheets coated the fiber core with a thickness of less than half a micron. For power generation, the thread or “fiber-shaped fluidic nanogenerator” (FFNG), as the authors call it, was connected to electrodes and immersed into flowing water or simply repeatedly dipped into a saline solution. “The electricity was derived from the relative movement between the FFNG and the solution,” the scientists explained. According to the theory, an electrical double layer is created around the fiber, and then the flowing solution distorts the symmetrical charge distribution, generating an electricity gradient along the long axis.

The power output efficiency of this system was high. Compared with other types of miniature energy-harvesting devices, the FFNG was reported to show a superior power conversion efficiency of more than 20%. Other advantages are elasticity, tunability, lightweight, and one-dimensionality, thus offering prospects of exciting technological applications. The FFNG can be made stretchable just by spinning the sheets around an elastic fiber substrate. If woven into fabrics, wearable electronics become thus a very interesting option for FFNG application. Another exciting application is the harvesting of electrical energy from the bloodstream for medical applications. First tests with frog nerves proved to be successful.

Here’s a link to and a citation for the paper,

A One-Dimensional Fluidic Nanogenerator with a High Power Conversion Efficiency by Yifan Xu, Dr. Peining Chen, Jing Zhang, Songlin Xie, Dr. Fang Wan, Jue Deng, Dr. Xunliang Cheng, Yajie Hu, Meng Liao, Dr. Bingjie Wang, Dr. Xuemei Sun, and Prof. Dr. Huisheng Peng. Angewandte Chemie International Edition DOI: 10.1002/anie.201706620 Version of Record online: 7 SEP 2017

© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Yarns that harvest and generate energy

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The researchers involved in this work are confident enough about their prospects that they will be  patenting their research into yarns. From an August 25, 2017 news item on Nanowerk,

An international research team led by scientists at The University of Texas at Dallas and Hanyang University in South Korea has developed high-tech yarns that generate electricity when they are stretched or twisted.

In a study published in the Aug. 25 [2017] issue of the journal Science (“Harvesting electrical energy from carbon nanotube yarn twist”), researchers describe “twistron” yarns and their possible applications, such as harvesting energy from the motion of ocean waves or from temperature fluctuations. When sewn into a shirt, these yarns served as a self-powered breathing monitor.

“The easiest way to think of twistron harvesters is, you have a piece of yarn, you stretch it, and out comes electricity,” said Dr. Carter Haines, associate research professor in the Alan G. MacDiarmid NanoTech Institute at UT Dallas and co-lead author of the article. The article also includes researchers from South Korea, Virginia Tech, Wright-Patterson Air Force Base and China.

An August 25, 2017 University of Texas at Dallas news release, which originated the news item, expands on the theme,

Yarns Based on Nanotechnology

The yarns are constructed from carbon nanotubes, which are hollow cylinders of carbon 10,000 times smaller in diameter than a human hair. The researchers first twist-spun the nanotubes into high-strength, lightweight yarns. To make the yarns highly elastic, they introduced so much twist that the yarns coiled like an over-twisted rubber band.

In order to generate electricity, the yarns must be either submerged in or coated with an ionically conducting material, or electrolyte, which can be as simple as a mixture of ordinary table salt and water.

“Fundamentally, these yarns are supercapacitors,” said Dr. Na Li, a research scientist at the NanoTech Institute and co-lead author of the study. “In a normal capacitor, you use energy — like from a battery — to add charges to the capacitor. But in our case, when you insert the carbon nanotube yarn into an electrolyte bath, the yarns are charged by the electrolyte itself. No external battery, or voltage, is needed.”

When a harvester yarn is twisted or stretched, the volume of the carbon nanotube yarn decreases, bringing the electric charges on the yarn closer together and increasing their energy, Haines said. This increases the voltage associated with the charge stored in the yarn, enabling the harvesting of electricity.

Stretching the coiled twistron yarns 30 times a second generated 250 watts per kilogram of peak electrical power when normalized to the harvester’s weight, said Dr. Ray Baughman, director of the NanoTech Institute and a corresponding author of the study.

“Although numerous alternative harvesters have been investigated for many decades, no other reported harvester provides such high electrical power or energy output per cycle as ours for stretching rates between a few cycles per second and 600 cycles per second.”

Lab Tests Show Potential Applications

In the lab, the researchers showed that a twistron yarn weighing less than a housefly could power a small LED, which lit up each time the yarn was stretched.

To show that twistrons can harvest waste thermal energy from the environment, Li connected a twistron yarn to a polymer artificial muscle that contracts and expands when heated and cooled. The twistron harvester converted the mechanical energy generated by the polymer muscle to electrical energy.

“There is a lot of interest in using waste energy to power the Internet of Things, such as arrays of distributed sensors,” Li said. “Twistron technology might be exploited for such applications where changing batteries is impractical.”

The researchers also sewed twistron harvesters into a shirt. Normal breathing stretched the yarn and generated an electrical signal, demonstrating its potential as a self-powered respiration sensor.

“Electronic textiles are of major commercial interest, but how are you going to power them?” Baughman said. “Harvesting electrical energy from human motion is one strategy for eliminating the need for batteries. Our yarns produced over a hundred times higher electrical power per weight when stretched compared to other weavable fibers reported in the literature.”

Electricity from Ocean Waves

“In the lab we showed that our energy harvesters worked using a solution of table salt as the electrolyte,” said Baughman, who holds the Robert A. Welch Distinguished Chair in Chemistry in the School of Natural Sciences and Mathematics. “But we wanted to show that they would also work in ocean water, which is chemically more complex.”

In a proof-of-concept demonstration, co-lead author Dr. Shi Hyeong Kim, a postdoctoral researcher at the NanoTech Institute, waded into the frigid surf off the east coast of South Korea to deploy a coiled twistron in the sea. He attached a 10 centimeter-long yarn, weighing only 1 milligram (about the weight of a mosquito), between a balloon and a sinker that rested on the seabed.

Every time an ocean wave arrived, the balloon would rise, stretching the yarn up to 25 percent, thereby generating measured electricity.

Even though the investigators used very small amounts of twistron yarn in the current study, they have shown that harvester performance is scalable, both by increasing twistron diameter and by operating many yarns in parallel.

“If our twistron harvesters could be made less expensively, they might ultimately be able to harvest the enormous amount of energy available from ocean waves,” Baughman said. “However, at present these harvesters are most suitable for powering sensors and sensor communications. Based on demonstrated average power output, just 31 milligrams of carbon nanotube yarn harvester could provide the electrical energy needed to transmit a 2-kilobyte packet of data over a 100-meter radius every 10 seconds for the Internet of Things.”

Researchers from the UT Dallas Erik Jonsson School of Engineering and Computer Science and Lintec of America’s Nano-Science & Technology Center also participated in the study.

The investigators have filed a patent on the technology.

In the U.S., the research was funded by the Air Force, the Air Force Office of Scientific Research, NASA, the Office of Naval Research and the Robert A. Welch Foundation. In Korea, the research was supported by the Korea-U.S. Air Force Cooperation Program and the Creative Research Initiative Center for Self-powered Actuation of the National Research Foundation and the Ministry of Science.

Here’s a link to and a citation for the paper,

Harvesting electrical energy from carbon nanotube yarn twist by Shi Hyeong Kim, Carter S. Haines, Na Li, Keon Jung Kim, Tae Jin Mun, Changsoon Choi, Jiangtao Di, Young Jun Oh, Juan Pablo Oviedo, Julia Bykova, Shaoli Fang, Nan Jiang, Zunfeng Liu, Run Wang, Prashant Kumar, Rui Qiao, Shashank Priya, Kyeongjae Cho, Moon Kim, Matthew Steven Lucas, Lawrence F. Drummy, Benji Maruyama, Dong Youn Lee, Xavier Lepró, Enlai Gao, Dawood Albarq, Raquel Ovalle-Robles, Seon Jeong Kim, Ray H. Baughman. Science 25 Aug 2017: Vol. 357, Issue 6353, pp. 773-778 DOI: 10.1126/science.aam8771

This paper is behind a paywall.

Dexter Johnson in an Aug. 25, 2017 posting on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) delves further into the research,

…

“Basically what’s happening is when we stretch the yarn, we’re getting a change in capacitance of the yarn. It’s that change that allows us to get energy out,” explains Carter Haines, associate research professor at UT Dallas and co-lead author of the paper describing the research, in an interview with IEEE Spectrum.

This makes it similar in many ways to other types of energy harvesters. For instance, in other research, it has been demonstrated—with sheets of rubber with coated electrodes on both sides—that you can increase the capacitance of a material when you stretch it and it becomes thinner. As a result, if you have charge on that capacitor, you can change the voltage associated with that charge.

“We’re more or less exploiting the same effect but what we’re doing differently is we’re using an electric chemical cell to do this,” says Haines. “So we’re not changing double layer capacitance in normal parallel plate capacitors. But we’re actually changing the electric chemical capacitance on the surface of a super capacitor yarn.”

While there are other capacitance-based energy harvesters, those other devices require extremely high voltages to work because they’re using parallel plate capacitors, according to Haines.

…

Dexter asks good questions and his post is very informative.

“Innovation and its enemies” and “Science in Wonderland”: a commentary on two books and a few thoughts about fish (1 of 2)

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There’s more than one way to approach the introduction of emerging technologies and sciences to ‘the public’. Calestous Juma in his 2016 book, ”Innovation and Its Enemies; Why People Resist New Technologies” takes a direct approach, as can be seen from the title while Melanie Keene’s 2015 book, “Science in Wonderland; The Scientific Fairy Tales of Victorian Britain” presents a more fantastical one. The fish in the headline tie together, thematically and tenuously, both books with a real life situation.

Innovation and Its Enemies

Calestous Juma, the author of “Innovation and Its Enemies” has impressive credentials,

  • Professor of the Practice of International Development,
  • Director of the Science, Technology, and Globalization Project at Harvard Kennedy School’s Better Science and International Affairs,
  • Founding Director of the African Centre for Technology Studies in Nairobi (Kenya),
  • Fellow of the Royal Society of London, and
  • Foreign Associate of the US National Academy of Sciences.

Even better, Juma is an excellent storyteller perhaps too much so for a book which presents a series of science and technology adoption case histories. (Given the range of historical time periods, geography, and the innovations themselves, he always has to stop short.)  The breadth is breathtaking and Juma manages with aplomb. For example, the innovations covered include: coffee, electricity, mechanical refrigeration, margarine, recorded sound, farm mechanization, and the printing press. He also covers two recently emerging technologies/innovations: transgenic crops and AquAdvantage salmon (more about the salmon later).

Juma provides an analysis of the various ways in which the public and institutions panic over innovation and goes on to offer solutions. He also injects a subtle note of humour from time to time. Here’s how Juma describes various countries’ response to risks and benefits,

In the United States products are safe until proven risky.

In France products are risky until proven safe.

In the United Kingdom products are risky even when proven safe.

In India products are safe when proven risky.

In Canada products are neither safe nor risky.

In Japan products are either safe or risky.

In Brazil products are both safe and risky.

In sub-Saharan Africa products are risky even if they do not exist. (pp. 4-5)

To Calestous Juma, thank you for mentioning Canada and for so aptly describing the quintessentially Canadian approach to not just products and innovation but to life itself, ‘we just don’t know; it could be this or it could be that or it could be something entirely different; we just don’t know and probably will never know.’.

One of the aspects that I most appreciated in this book was the broadening of the geographical perspective on innovation and emerging technologies to include the Middle East, China, and other regions/countries. As I’ve  noted in past postings, much of the discussion here in Canada is Eurocentric and/or UScentric. For example, the Council of Canadian Academies which conducts assessments of various science questions at the request of Canadian and regional governments routinely fills the ‘international’ slot(s) for their expert panels with academics from Europe (mostly Great Britain) and/or the US (or sometimes from Australia and/or New Zealand).

A good example of Juma’s expanded perspective on emerging technology is offered in Art Carden’s July 7, 2017 book review for Forbes.com (Note: A link has been removed),

In the chapter on coffee, Juma discusses how Middle Eastern and European societies resisted the beverage and, in particular, worked to shut down coffeehouses. Islamic jurists debated whether the kick from coffee is the same as intoxication and therefore something to be prohibited. Appealing to “the principle of original permissibility — al-ibaha, al-asliya — under which products were considered acceptable until expressly outlawed,” the fifteenth-century jurist Muhamad al-Dhabani issued several fatwas in support of keeping coffee legal.

This wasn’t the last word on coffee, which was banned and permitted and banned and permitted and banned and permitted in various places over time. Some rulers were skeptical of coffee because it was brewed and consumed in public coffeehouses — places where people could indulge in vices like gambling and tobacco use or perhaps exchange unorthodox ideas that were a threat to their power. It seems absurd in retrospect, but political control of all things coffee is no laughing matter.

The bans extended to Europe, where coffee threatened beverages like tea, wine, and beer. Predictably, and all in the name of public safety (of course!), European governments with the counsel of experts like brewers, vintners, and the British East India Tea Company regulated coffee importation and consumption. The list of affected interest groups is long, as is the list of meddlesome governments. Charles II of England would issue A Proclamation for the Suppression of Coffee Houses in 1675. Sweden prohibited coffee imports on five separate occasions between 1756 and 1817. In the late seventeenth century, France required that all coffee be imported through Marseilles so that it could be more easily monopolized and taxed.

Carden who teaches economics at Stanford University (California, US) focuses on issues of individual liberty and the rule of law with regards to innovation. I can appreciate the need to focus tightly when you have a limited word count but Carden could have a spared a few words to do more justice to Juma’s comprehensive and focused work.

At the risk of being accused of the fault I’ve attributed to Carden, I must mention the printing press chapter. While it was good to see a history of the printing press and attendant social upheavals noting its impact and discovery in regions other than Europe; it was shocking to someone educated in Canada to find Marshall McLuhan entirely ignored. Even now, I believe it’s virtually impossible to discuss the printing press as a technology, in Canada anyway, without mentioning our ‘communications god’ Marshall McLuhan and his 1962 book, The Gutenberg Galaxy.

Getting back to Juma’s book, his breadth and depth of knowledge, history, and geography is packaged in a relatively succinct 316 pp. As a writer, I admire his ability to distill the salient points and to devote chapters on two emerging technologies. It’s notoriously difficult to write about a currently emerging technology and Juma even managed to include a reference published only months (in early 2016) before “Innovation and its enemires” was published in July 2016.

Irrespective of Marshall McLuhan, I feel there are a few flaws. The book is intended for policy makers and industry (lobbyists, anyone?), he reaffirms (in academia, industry, government) a tendency toward a top-down approach to eliminating resistance. From Juma’s perspective, there needs to be better science education because no one who is properly informed should have any objections to an emerging/new technology. Juma never considers the possibility that resistance to a new technology might be a reasonable response. As well, while there was some mention of corporate resistance to new technologies which might threaten profits and revenue, Juma didn’t spare any comments about how corporate sovereignty and/or intellectual property issues are used to stifle innovation and quite successfully, by the way.

My concerns aside, testimony to the book’s worth is Carden’s review almost a year after publication. As well, Sir Peter Gluckman, Chief Science Advisor to the federal government of New Zealand, mentions Juma’s book in his January 16, 2017 talk, Science Advice in a Troubled World, for the Canadian Science Policy Centre.

Science in Wonderland

Melanie Keene’s 2015 book, “Science in Wonderland; The scientific fairy tales of Victorian Britain” provides an overview of the fashion for writing and reading scientific and mathematical fairy tales and, inadvertently, provides an overview of a public education programme,

A fairy queen (Victoria) sat on the throne of Victoria’s Britain, and she presided over a fairy tale age. The nineteenth century witnessed an unprecedented interest in fairies and in their tales, as they were used as an enchanted mirror in which to reflection question, and distort contemporary society.30  …  Fairies could be found disporting themselves thought the century on stage and page, in picture and print, from local haunts to global transports. There were myriad ways in which authors, painters, illustrators, advertisers, pantomime performers, singers, and more, capture this contemporary enthusiasm and engaged with fairyland and folklore; books, exhibitions, and images for children were one of the most significant. (p. 13)

…

… Anthropologists even made fairies the subject of scientific analysis, as ‘fairyology’ determined whether fairies should be part of natural history or part of supernatural lore; just on aspect of the revival of interest in folklore. Was there a tribe of fairy creatures somewhere out thee waiting to be discovered, across the globe of in the fossil record? Were fairies some kind of folks memory of any extinct race? (p. 14)

…

Scientific engagements with fairyland was widespread, and not just as an attractive means of packaging new facts for Victorian children.42 … The fairy tales of science had an important role to play in conceiving of new scientific disciplines; in celebrating new discoveries; in criticizing lofty ambitions; in inculcating habits of mind and body; in inspiring wonder; in positing future directions; and in the consideration of what the sciences were, and should be. A close reading of these tales provides a more sophisticated understanding of the content and status of the Victorian sciences; they give insights into what these new scientific disciplines were trying to do; how they were trying to cement a certain place in the world; and how they hoped to recruit and train new participants. (p. 18)

Segue: Should you be inclined to believe that society has moved on from fairies; it is possible to become a certified fairyologist (check out the fairyologist.com website).

“Science in Wonderland,” the title being a reference to Lewis Carroll’s Alice, was marketed quite differently than “innovation and its enemies”. There is no description of the author, as is the protocol in academic tomes, so here’s more from her webpage on the University of Cambridge (Homerton College) website,

Role:
Fellow, Graduate Tutor, Director of Studies for History and Philosophy of Science

Getting back to Keene’s book, she makes the point that the fairy tales were based on science and integrated scientific terminology in imaginative ways although some books with more success than other others. Topics ranged from paleontology, botany, and astronomy to microscopy and more.

This book provides a contrast to Juma’s direct focus on policy makers with its overview of the fairy narratives. Keene is primarily interested in children but her book casts a wider net  “… they give insights into what these new scientific disciplines were trying to do; how they were trying to cement a certain place in the world; and how they hoped to recruit and train new participants.”

In a sense both authors are describing how technologies are introduced and integrated into society. Keene provides a view that must seem almost halcyon for many contemporary innovation enthusiasts. As her topic area is children’s literature any resistance she notes is primarily literary invoking a debate about whether or not science was killing imagination and whimsy.

It would probably help if you’d taken a course in children’s literature of the 19th century before reading Keene’s book is written . Even if you haven’t taken a course, it’s still quite accessible, although I was left wondering about ‘Alice in Wonderland’ and its relationship to mathematics (see Melanie Bayley’s December 16, 2009 story for the New Scientist for a detailed rundown).

As an added bonus, fairy tale illustrations are included throughout the book along with a section of higher quality reproductions.

One of the unexpected delights of Keene’s book was the section on L. Frank Baum and his electricity fairy tale, “The Master Key.” She stretches to include “The Wizard of Oz,” which doesn’t really fit but I can’t see how she could avoid mentioning Baum’s most famous creation. There’s also a surprising (to me) focus on water, which when it’s paired with the interest in microscopy makes sense. Keene isn’t the only one who has to stretch to make things fit into her narrative and so from water I move onto fish bringing me back to one of Juma’s emerging technologies

Part 2: Fish and final comments

New electrical contact technology to exploit nanoscale catalytic effects

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A Jan. 20,, 2017 news item on Nanotechnology Now announces research into nanoscale electrical contact technology,

Research by scientists at Swansea University [UK] is helping to meet the challenge of incorporating nanoscale structures into future semiconductor devices that will create new technologies and impact on all aspects of everyday life.

Dr Alex Lord and Professor Steve Wilks from the Centre for Nanohealth led the collaborative research published in Nano Letters. The research team looked at ways to engineer electrical contact technology on minute scales with simple and effective modifications to nanowires that can be used to develop enhanced devices based on the nanomaterials. Well-defined electrical contacts are essential for any electrical circuit and electronic device because they control the flow of electricity that is fundamental to the operational capability.

Everyday materials that are being scaled down to the size of nanometres (one million times smaller than a millimetre on a standard ruler) by scientists on a global scale are seen as the future of electronic devices. The scientific and engineering advances are leading to new technologies such as energy producing clothing to power our personal gadgets and sensors to monitor our health and the surrounding environment.

Over the coming years this will make a massive contribution to the explosion that is the Internet of Things connecting everything from our homes to our cars into a web of communication. All of these new technologies require similar advances in electrical circuits and especially electrical contacts that allow the devices to work correctly with electricity.

A Jan. 19, 2017 Swansea University press release (also on EurekAlert), which originated the news item, explains in greater detail,

Professor Steve Wilks said: “Nanotechnology has delivered new materials and new technologies and the applications of nanotechnology will continue to expand over the coming decades with much of its usefulness stemming from effects that occur at the atomic- or nano-scale. With the advent of nanotechnology, new technologies have emerged such as chemical and biological sensors, quantum computing, energy harvesting, lasers, and environmental and photon-detectors, but there is a pressing need to develop new electrical contact preparation techniques to ensure these devices become an everyday reality.”

“Traditional methods of engineering electrical contacts have been applied to nanomaterials but often neglect the nanoscale effects that nanoscientists have worked so hard to uncover.  Currently, there isn’t a design toolbox to make electrical contacts of chosen properties to nanomaterials and in some respects the research is lagging behind our potential application of the enhanced materials.”

The Swansea research team1 used specialist experimental equipment and collaborated with Professor Quentin Ramasse of the SuperSTEM Laboratory, Science and Facilities Technology Council.  The scientists were able to physically interact with the nanostructures and measure how the nanoscale modifications affected the electrical performance.2 

Their experiments found for the first time, that simple changes to the catalyst edge can turn-on or turn-off the dominant electrical conduction and most importantly reveal a powerful technique that will allow nanoengineers to select the properties of manufacturable nanowire devices.

Dr Lord said: “The experiments had a simple premise but were challenging to optimise and allow atomic-scale imaging of the interfaces. However, it was essential to this study and will allow many more materials to be investigated in a similar way.”

“This research now gives us an understanding of these new effects and will allow engineers in the future to reliably produce electrical contacts to these nanomaterials which is essential for the materials to be used in the technologies of tomorrow.

“In the near future this work can help enhance current nanotechnology devices such as biosensors and also lead to new technologies such as Transient Electronics that are devices that diminish and vanish without a trace which is an essential property when they are applied as diagnostic tools inside the human body.”

References
1. Lord, A. M., Ramasse, Q. M., Kepaptsoglou, D. M., Evans, J. E., Davies, P. R., Ward, M. B. & Wilks, S. P. 2016 Modifying the Interface Edge to Control the Electrical Transport Properties of Nanocontacts to Nanowires. Nano Lett. (doi:10.1021/acs.nanolett.6b03699). http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.6b03699
2 .Lord, A. M. et al. 2015 Controlling the electrical transport properties of nanocontacts to nanowires. Nano Lett. 15, 4248–4254. (doi:10.1021/nl503743t) http://pubs.acs.org/doi/abs/10.1021/nl503743t

Both papers are open access.