Category Archives: Applications

A future android brain like that of Star Trek’s Commander Data might contain neuristors, multi-circuit components that emulate the firings of human neurons.

Neuristors already exist today in labs, in small quantities, and to fuel the quest to boost neuristors’ power and numbers for practical use in brain-like computing, the U.S. Department of Defense has awarded a $7.1 million grant to a research team led by the Georgia Institute of Technology. The researchers will mainly expand work on new metal oxide materials that buzz electronically at the nanoscale to emulate the way human neural networks buzz with electric potential on a cellular level.

But let’s walk expectations back from the distant sci-fi future into the scientific present: The research team has developed neuristor materials to build, for now, an intelligent light sensor, and not some artificial version of the human brain, which would require hundreds of trillions of circuits.

“We’re not going to reach circuit complexities of that magnitude, not even a tenth,” said Alan Doolittle, a professor at Georgia Tech’s School of Electrical and Computer Engineering. “Also, currently science doesn’t really know yet very well how the human brain works, so we can’t duplicate it.”

Intelligent retina

But an artificial retina that can learn autonomously appears well within reach of the research team from Georgia Tech and Binghamton University. Despite the term “retina,” the development is not intended as a medical implant, but it could be used in advanced image recognition cameras for national defense and police work.

At the same time, it significantly advances brain-mimicking, or neuromorphic, computing. The research field that takes its cues from what science already does know about how the brain computes to develop exponentially more powerful computing.

The retina is comprised of an array of ultra-compact circuits called neuristors (a word combining “neuron” and “transistor”) that sense light, compute an image out of it and store the image. All three of the functions would occur simultaneously and nearly instantaneously.

“The same device senses, computes and stores the image,” Doolittle said. “The device is the sensor, and it’s the processor, and it’s the memory all at the same time.” A neuristor itself is comprised in part of devices called memristors inspired by the way human neurons work.

Brain vs. PC

That cuts out loads of processing and memory lag time that are inherent in traditional computing.

Take the device you’re reading this article on: Its microprocessor has to tap a separate memory component to get data, then do some processing, tap memory again for more data, process some more, etc. “That back-and-forth from memory to microprocessor has created a bottleneck,” Doolittle said.

A neuristor array breaks the bottleneck by emulating the extreme flexibility of biological nervous systems: When a brain computes, it uses a broad set of neural pathways that flash with enormous data. Then, later, to compute the same thing again, it will use quite different neural paths.

Traditional computer pathways, by contrast, are hardwired. For example, look at a present-day processor and you’ll see lines etched into it. Those are pathways that computational signals are limited to.

The new memristor materials at the heart of the neuristor are not etched, and signals flow through the surface very freely, more like they do through the brain, exponentially increasing the number of possible pathways computation can take. That helps the new intelligent retina compute powerfully and swiftly.

Terrorists, missing children

The retina’s memory could also store thousands of photos, allowing it to immediately match up what it sees with the saved images. The retina could pinpoint known terror suspects in a crowd, find missing children, or identify enemy aircraft virtually instantaneously, without having to trawl databases to correctly identify what is in the images.

Even if you take away the optics, the new neuristor arrays still advance artificial intelligence. Instead of light, a surface of neuristors could absorb massive data streams at once, compute them, store them, and compare them to patterns of other data, immediately. It could even autonomously learn to extrapolate further information, like calculating the third dimension out of data from two dimensions.

“It will work with anything that has a repetitive pattern like radar signatures, for example,” Doolittle said. “Right now, that’s too challenging to compute, because radar information is flying out at such a high data rate that no computer can even think about keeping up.”

Smart materials

The research project’s title acronym CEREBRAL may hint at distant dreams of an artificial brain, but what it stands for spells out the present goal in neuromorphic computing: Cross-disciplinary Electronic-ionic Research Enabling Biologically Realistic Autonomous Learning.

The intelligent retina’s neuristors are based on novel metal oxide nanotechnology materials, unique to Georgia Tech. They allow computing signals to flow flexibly across pathways that are electronic, which is customary in computing, and at the same time make use of ion motion, which is more commonly know from the way batteries and biological systems work.

The new materials have already been created, and they work, but the researchers don’t yet fully understand why.

Much of the project is dedicated to examining quantum states in the materials and how those states help create useful electronic-ionic properties. Researchers will view them by bombarding the metal oxides with extremely bright x-ray photons at the recently constructed National Synchrotron Light Source II.

Grant sub-awardee Binghamton University is located close by, and Binghamton physicists will run experiments and hone them via theoretical modeling.

‘Sea of lithium’

The neuristors are created mainly by the way the metal oxide materials are grown in the lab, which has some advantages over building neuristors in a more wired way.

This materials-growing approach to creating part of the computational structure is conducive to mass production. Also, though neuristors in general free signals to take multiple pathways, Georgia Tech’s neuristors do it much more flexibly thanks to chemical properties.

“We also have a sea of lithium, and it’s like an infinite reservoir of computational ionic fluid,” Doolittle said. The lithium niobite imitates the way ionic fluid bathes biological neurons and allows them to flash with electric potential while signaling. In a neuristor array, the lithium niobite helps computational signaling move in myriad directions.

“It’s not like the typical semiconductor material, where you etch a line, and only that line has the computational material,” Doolittle said.

Commander Data’s brain?

“Unlike any other previous neuristors, our neuristors will adapt themselves in their computational-electronic pulsing on the fly, which makes them more like a neurological system,” Doolittle said. “They mimic biology in that we have ion drift across the material to create the memristors (the memory part of neuristors).”

Brains are far superior to computers at most things, but not all. Brains recognize objects and do motor tasks much better. But computers are much better at arithmetic and data processing.

Neuristor arrays can meld both types of computing, making them biological and algorithmic at once, a bit like Commander Data’s brain.

NanoString Technologies, Inc. (Nasdaq:NSTG), a provider of life science tools for translational research and molecular diagnostic products, and Lam Research Corporation (Nasdaq:LRCX), a global supplier of wafer fabrication equipment and services to the semiconductor industry, today announced a strategic collaboration to develop NanoString’s proprietary Hyb & Seq next-generation sequencing platform.

This collaboration brings together NanoString’s proprietary sequencing chemistry and Lam’s expertise in advanced systems engineering to enable nanoscale manufacturing, with the goal of building a clinical sequencer with the simplest workflow in the industry. The objectives of the collaboration are to complete the development of the Hyb & Seq single molecule sequencing chemistry, design and engineer a clinical sequencing instrument, develop clinical assay panels, and secure the necessary regulatory approvals.  In addition, the companies intend to explore methods for coupling the sequencing chemistry with advanced semiconductor fabrication processes to optimize the performance of molecular profiling platforms.

Under the terms of the collaboration, Lam will provide up to $50 million of funding intended to cover the costs of development and regulatory approval over a development period expected to last approximately three years, as well as advanced engineering and technical support. Lam will receive a warrant to purchase one million shares of NanoString common stock at $16.75 per share, as well as a royalty on all products developed under the collaboration. NanoString retains all rights to commercialize the resulting Hyb & Seq products, and the parties will share ownership rights in jointly developed intellectual property.

“We are excited to collaborate with Lam Research, in a partnership that brings together leading innovators in our respective fields,” said Brad Gray, NanoString’s President and Chief Executive Officer. “By combining our Hyb & Seq technology with Lam’s advanced engineering expertise, we intend to fully resource the development of the industry’s simplest clinical sequencer, and enable open-ended innovation at the intersection of semiconductors and genomics.”

“Our vision is to create value from natural technology extensions, including nanoscale applications enablement, chemistry, plasma, fluidics, and advanced systems engineering,” stated Martin Anstice, Lam Research’s President and Chief Executive Officer. “We are excited to collaborate with NanoString to advance the development of their novel Hyb & Seq system and chemistry to meet the challenge of increasing our understanding of human genetics, and we envision a number of strategic benefits by aligning our complementary respective strengths. This is a compelling opportunity for the whole to be significantly greater than the sum of its parts; it is an accelerator of enablement and value for both companies.”

Intel Corporation (NASDAQ:INTC) and Mobileye N.V. (NYSE:MBLY) today announced the completion of Intel’s tender offer for outstanding ordinary shares of Mobileye. The acquisition is expected to accelerate innovation for the automotive industry and positions Intel as a technology provider in the fast-growing market for highly and fully autonomous vehicles.

The combination of Intel and Mobileye will allow Mobileye’scomputer vision expertise (the “eyes”) to complement Intel’s high-performance computing and connectivity expertise (the “brains”) to create automated driving solutions from cloud to car. Intel estimates the vehicle systems, data and services market opportunity to be up to $70 billion by 2030.

“With Mobileye, Intel emerges as a leader in creating the technology foundation that the automotive industry needs for an autonomous future,” said Intel CEO Brian Krzanich. “It’s an exciting engineering challenge and a huge growth opportunity for Intel. Even more exciting is the potential for autonomous cars to transform industries, improve society and save millions of lives.”

Intel’s Automated Driving Group (ADG) will combine its operations with Mobileye, an Intel Company. The combined Mobileye organization will lead Intel’s autonomous driving efforts, and will have the full support of Intel resources and technology to define and deliver cloud-to-car solutions for the automotive market segment. Mobileye will remain headquartered in Israel and led by Prof. Amnon Shashua who will serve as Intel senior vice president and Mobileye CEO and chief technology officer. In addition, Ziv Aviram, Mobileye co-founder, president and CEO, is retiring from the company, effective immediately.

“Leading in autonomous driving technology requires a combination of innovative proprietary software products and versatile open-system hardware platforms that enable customers and partners to customize solutions,” said Prof. Amnon Shashua. “For the first time, the auto industry has a single partner with deep expertise and a cultural legacy in both areas. Mobileye is very excited to begin this new chapter.”

Mobileye will support and build on both companies’ existing technology and customer relationships with automakers, tier-1 suppliers and semiconductor partners to develop advanced driving assist, highly autonomous and fully autonomous driving programs.

Energy loss due to scattering from material defects is known to set limits on the performance of nearly all technologies that we employ for communications, timing, and navigation. In micro-mechanical gyroscopes and accelerometers, such as those commonly found in cellphones today, microstructural disorder impacts measurement drift and overall accuracy of the sensor, analogous to how a dirty violin string might impact one’s enjoyment of beautiful music. In optical fiber communication systems, scattering from material defects can reduce data fidelity over long distances thereby reducing achievable bandwidth. Since defect-free materials cannot be obtained, how can we possibly improve on the fundamental technological limits imposed by disorder?

A research collaboration between the University of Illinois at Urbana-Champaign, the National Institute of Standards and Technology, and the University of Maryland has revealed a new technique by which scattering of sound waves from disorder in a material can be suppressed on demand. All of this, can be simply achieved by illuminating with the appropriate color of laser light. The result, which is published in Nature Communications, could have a wide-ranging impact on sensors and communication systems.

This is a microscope image of a silica glass resonator and optical fiber waveguide. Light and sound circulating in this type of resonator are shown to exhibit chiral effects in this study. (Credit:  Gaurav Bahl, University of Illinois Department of Mechanical Science and Engineering)

This is a microscope image of a silica glass resonator and optical fiber waveguide. Light and sound circulating in this type of resonator are shown to exhibit chiral effects in this study. (Credit: Gaurav Bahl, University of Illinois Department of Mechanical Science and Engineering)

Gaurav Bahl, an assistant professor of mechanical science and engineering, and his research team have been studying the interaction of light with sound in solid state micro-resonators. This new result is the culmination of a series of experiments pursued by his team over the past several years, and a new scientific question posed in the right place.

“Resonators can be thought of as echo chambers for sound and light, and can be as simple as micro-spherical balls of glass like those we used in our study,” Bahl explained. “Our research community has long understood that light can be used to create and amplify sound waves in resonators through a variety of optical forces. The resonant echoes help to increase the interaction time between sound, light, and material disorder, making these subtle effects much easier to observe and control. Since interactions within resonators are fundamentally no different from those taking place in any other system, these can be a really compact platform for exploring the underlying physics.”

The key to suppressing scattering from disorder is to induce a mismatch in the propagation between the original and scattered directions. This idea is similar to how an electric current prefers to flow along the path of least resistance, or how water prefers to flow through a wider pipe rather than a constricted one. To suppress back-scattering of forward-moving sound waves, one must create a large acoustic impedance in the backward direction. This asymmetry for forward and backward propagating waves is termed as chirality of the medium. Most solid-state systems do not have chiral properties, but these properties can be induced through magnetic fields or through space-time variation of the medium.

“A few years ago, we discovered that chirality can be induced for light using an opto-mechanical phenomenon, in which light couples with propagating sound waves and renders the medium transparent. Our experiments at that time showed that the induced optical transparency only allows light to move unidirectionally, that is, it creates a preferentially low optical impedance in one direction,” Bahl said. “It is then that we met our collaborator Jacob Taylor, a physicist at NIST, who asked us a simple question. What happens to the sound waves in such a system?”

“Our theoretical modeling predicted that having a chiral system for sound propagation could suppress any back-scattering that may have been induced by disorder,” explained Taylor. “This concept arose from work we’ve been doing in the past few years investigating topological protection for light, where chiral propagation is a key feature for improving the performance of devices. Initially the plan with Bahl’s team was just to show a difference between the forward and backward propagating sound waves, using a cooling effect created by light. But the system surprised us with an even stronger practical effect than expected.”

That simple question launched a new multi-year research effort in a direction that has not been explored previously. Working in close collaboration, the team discovered that Brillouin light scattering, a specific kind of opto-mechanical interaction, could also induce chirality for sound waves. Between the experimental tools in Bahl’s lab, and the theoretical advancements in Taylor’s lab, the pieces of the puzzle were already in place.

“We experimentally prepared a chiral optomechanical system by circulating a laser field in the clockwise direction in a silica glass resonator. The laser wavelength, or color, was specially arranged to induce optical damping of only clockwise sound waves. This created a large acoustic impedance mismatch between clockwise and counter-clockwise directions of propagation,” explained Seunghwi Kim, first author of the study. “Sound waves that were propagating the clockwise direction experienced very high losses due to the opto-mechanical cooling effect. Sound waves moving in the counter-clockwise direction could move freely. Surprisingly, we saw a huge reduction of scattering loss for counter-clockwise sound waves, since those waves could no longer scatter into the clockwise direction! In other words, even though disorder was present in the resonator, its action was suppressed.”

Just as sound is the primary method of voice communication between humans, electromagnetic waves like radio and light are the primary technology used for global communications. What could this discovery mean for the communications industry? Disorder and material defects are unavoidable optical fiber systems, resulting in lower data fidelity, bit errors, and bandwidth limitations. The team believes that technologies based on this discovery could be leveraged to circumvent the impact of unavoidable material defects in such systems.

“We’ve seen already that many sensors, such as those found in your phone or in your car, can be limited by intrinsic defects in the materials,” added Taylor. “The approach introduced here provides a simple means of circumventing those challenges, and may even help us approach the limits set by quantum mechanics, rather than our own engineering challenges.”

Practical applications of this result may not be too many years off. Reduction of mechanical losses could also directly improve mechanics-based inertial navigation sensors that we use today. Examples that we encounter in daily life are accelerometers and gyroscopes, without which our mobile phones would be a lot less capable, and our cars and airplanes a lot less safe.

NXP Semiconductors N.V. (NASDAQ:NXPI) announced a $22 million dollar program that expands its operations in the United States, enabling the Company’s US facilities to manufacture security chips for government applications that can support critical US national and homeland security programs. Upon completion of the expansion project, NXP facilities in Austin and Chandler will be certified to manufacture finished products that exceed the highest domestic and international security and quality standards.

“This initiative advances NXP’s long-term commitment to developing secure ID solutions for federal, state and local government programs in the United States and demonstrates our deep dedication to serving the American market,” said Ruediger Stroh, Executive Vice President of Security and Connectivity at NXP. “The expansion program further positions NXP to deliver solutions for the IoT, connected devices and many other fast-growing applications in the United States as we continue to be a major contributor to the country’s global leadership in the semiconductor industry.”

As the market leader in secure identification solutions, NXP’s proven technology is included in core components that power secure government-issued ID documents in more than 120 countries, and is used by 95 countries worldwide to secure electronic passport programs.

Steve Adler, the Mayor of Austin, said, “We are excited to see NXP investing in Austin and in the cyber security of our country. We trust this initiative will also secure thousands of jobs and further foster the growth of Austin as a major technology hub.”

NXP R&D manufacturing facilities in San Jose, Austin and Chandler have also undergone a thorough security cite certification process to produce Common Criteria EAL6+ SmartMX microcontroller family products. Common Criteria is an international set of guidelines and specifications developed for evaluating information security products to ensure they meet a rigorous security standard for government deployments.

Knowles Corporation (NYSE: KN) today announced the appointment of Dr. Cheryl Shavers to the Board of Directors. Her appointment is effective August 1, 2017 and expands the Board to 9 directors, 8 of whom are independent.

Dr. Cheryl Shavers currently serves as Chief Executive Officer of Global Smarts, Inc. an advisory services and strategy firm which she founded in 2001. In this role, she consults small and established businesses as well as government agencies on managing growth opportunities and the innovative process. Between 1999 and 2001, Dr. Shavers served as the Undersecretary of Commerce for Technology at the U.S. Department of Commerce, where she oversaw the Office of Technology Policy and the Technology Administration, the focal point for partnerships between the US government and the private sector pertaining to commercial and industrial innovation, productivity and economic growth. She also oversaw the National Institute of Standards and Technology, the National Technical Information Service and the Office of Space Commercialization. Dr. Shavers was one of the highest-ranking technologists in the Clinton Administration at the time. Prior to joining the Clinton administration, she held a variety of roles at Intel Corporation and Hewlett-Packard, including director of Emerging Technologies and sector manager of the Microprocessor Products Group for Intel. Dr. Shavers also is a director of Rockwell Collins.

Dr. Shavers holds a doctorate in Solid State Chemistry and a bachelor’s degree in Chemistry from Arizona State University.

“I am excited to have Dr. Shavers as a member of the Board of Directors. She has a remarkable strategic mind and brings extensive experience with technology development, innovation and management of growth opportunities to the Board, which will be invaluable to the Company,” stated Jean-Pierre Ergas, Knowles’ Chairman.

Dr. Shavers has been appointed to serve on the Audit Committee and the Governance and Nominating Committee.

 

Producers sometimes face challenges that go deep into the soil. They need answers to help the soil, on site. A portable field sensor can accurately measure minerals in soils more easily and efficiently than existing methods. And a research team, including a middle school student and her scientist father, can confirm it.

Calcium, like other minerals, is necessary for healthy plant growth. However, an excess of calcium — particularly in the form of calcium carbonate — can cause issues as it builds up in the soil.

“Calcium carbonate is basically a type of salt. It dissolves in water after a rainfall event and moves down through the soil,” explains David Weindorf. Weindorf is at the Department of Plant and Soil Science at Texas Tech University.

One main source of this calcium is limestone. At low levels, it makes thin threads or small white masses in the soil. However, in extreme cases it can actually take over the entire subsoil. Its hard surface can limit the ability of plant roots to grow. Getting this information on-the-fly is important for growers and soil scientists solving problems in the field.

Traditionally, soil scientists use their expertise to look at the soil and determine the stage of the calcium visually. There are also laboratory-based techniques that are very accurate, but they are not portable. The researchers wanted to see if a portable x-ray device — called PXRF, portable x-ray fluorescence spectrometry — would be better.

Based on their comparisons, the researchers found that, indeed, the device is a good method for measuring the calcium in the soil. The device can provide data on about 20 different elements, all in 60 seconds.

This can be a big advantage for soil scientists working in the field. It can also help scientists and farmers in developing countries who can’t afford expensive laboratory tests, or don’t have the expertise to visually appraise the soil.

“We are not advocating doing away with traditional assessment. We are simply providing a new data stream to help field soil scientists when evaluating carbonates in the field,” Weindorf explains. “Essentially, PXRF is another tool in the tool belt of the modern soil scientist, but it is by no means the only tool.”

Weindorf’s daughter was also part of the research. For Camille, this study was a way to branch out for her school’s science fair and do some original research. She scanned the soil samples and then helped her father perform the laboratory tests. She also helped calculate the summary statistics and write the paper.

“As a father, I just can’t overemphasize how proud I am of my daughter for taking on this science challenge with me,” he says. “I hope a project like this can inspire other students around her age to engage in original scientific inquiry. Truly, they are the future which will keep our country at the forefront of scientific innovation.”

Analog Devices, Inc. (ADI) today announced that it has become an affiliate member of Mcity at the University of Michigan. Mcity is a public-private partnership led by the University of Michigan to advance connected and automated vehicles. Among Mcity’s key initiatives is operating the Mcity Test Facility, which is the first purpose-built proving ground for testing connected and automated vehicles and technologies in simulated urban and suburban driving environments. Analog Devices will use the facility to test and refine future products in its Drive360 suite of technologies, including 28nm CMOS RADAR, solid state LIDAR, and high performance inertial measurement units for automated and autonomous driving applications.

By joining Mcity, ADI is committing to support the autonomous driving ecosystem as a premier semiconductor solutions provider and will use Mcity to understand market requirements through collaboration across the automotive design chain to bring connected and automated vehicle technologies to the commercial market.

ADI joins ranks with Mcity’s more than 65 industry members, which all play a role in creating a viable ecosystem to support connected and automated vehicles, including auto manufacturers and major parts suppliers, as well as vehicle communications, traffic infrastructure, and insurance companies, among others.

“Organizations like Mcity provide an important stage for testing products in real-world scenarios and for gathering real-time feedback from our customers and other key players in the autonomous driving ecosystem,” said Chris Jacobs, vice president, Autonomous Transportation and Safety, Analog Devices. “Working with the initiative will help shape our product and technology strategy by creating an open line of communication with customers and other industry leaders. This powerful connection will allow us to directly identify and address the toughest challenges to enable autonomous transportation.”

Three leading U.S. universities are the latest recipients of funding from the Nano-Bio Manufacturing Consortium (NBMC), operated by SEMI.  NBMC’s mission is to further the development of human performance monitoring (HPM), thereby broadening the use of advanced electronics in this highly anticipated application space. Among other applications, HPMs are expanding the fast growing wearable electronics markets. According to Research and Markets, “The global market for wearable electronic devices was valued at around USD $20 billion in 2016 and is expected to reach USD $97.8 billion, growing at a CAGR of around 24.1 percent from 2017 to 2023.”

The new awards announced today total more than $870,000 and include:

  • University of Arizona: To meet the needs of NBMC industry members, the University of Arizona will focus on determining which HPM sweat patch configuration is best suited to meeting performance requirements. The initial investigation will include a “lab-in-a-bandage” that collects and analyzes biomarkers within one minute from sweat secretion.  The follow-on project will determine the feasibility of using organic semiconductor sensor technology (compatible with flexible substrates and manufacturing techniques) for sweat biomarker detection sensitivity and selectivity with sweat sample volumes in the nano- and pico-liter range.
  • University of California at Los Angeles: UCLA will partner with i3 Electronics of Binghamton, NY to investigate the use of Fan-Out Wafer Level Packaging (FOWLP) methods as a new way to build versatile, biocompatible physically-flexible heterogeneous electronic systems. FOWLP is a relatively new packaging process that gaining widespread use in portable devices such as smart phones. It offers the advantages of true heterogeneous integration of different dies, including high performance electronics, tight pitch interconnects, and components (such as low profile passives) with a short turn-around, scalable, manufacturing process.
  • University of Massachusetts at Amherst: U Mass Amherst will conduct a detailed systematic assessment of microfluidic subsystem architecture and operational approaches for sweat-based biomarker detection.  The study will address issues associated with accurate, time-stamped sweat sample collection and delivery, effluent control and removal for continuous operation, and dynamic performance design aspects to address sample handling under conditions of high and low sweat rates.

“The NBMC program continues to push technology limits in ways that integrate leading edge microelectronics,” said Dr. Melissa Grupen-Shemansky, SEMI’s CTO for flexible electronics and advanced packaging.  “Consequently, SEMI is helping to identify new equipment, materials and process opportunities for our members and their customers.”

The NBMC program is funded through a cooperative agreement with the Air Force Research Laboratory in Dayton, Ohio.

Imagine slipping into a jacket, shirt or skirt that powers your cell phone, fitness tracker and other personal electronic devices as you walk, wave and even when you are sitting.

A new, ultrathin energy harvesting system developed at Vanderbilt University’s Nanomaterials and Energy Devices Laboratory has the potential to do just that. Based on battery technology and made from layers of black phosphorus that are only a few atoms thick, the new device generates small amounts of electricity when it is bent or pressed even at the extremely low frequencies characteristic of human motion.

“In the future, I expect that we will all become charging depots for our personal devices by pulling energy directly from our motions and the environment,” said Assistant Professor of Mechanical Engineering Cary Pint, who directed the research.

The new energy harvesting system is described in a paper titled “Ultralow Frequency Electrochemical Mechanical Strain Energy Harvester using 2D Black Phosphorus Nanosheets” published Jun.21 online by the journal ACS Energy Letters.

“This is timely and exciting research given the growth of wearable devices such as exoskeletons and smart clothing, which could potentially benefit from Dr. Pint’s advances in materials and energy harvesting,” observed Karl Zelik, assistant professor of mechanical and biomedical engineering at Vanderbilt, an expert on the biomechanics of locomotion who did not participate in the device’s development.

Currently, there is a tremendous amount of research aimed at discovering effective ways to tap ambient energy sources. These include mechanical devices designed to extract energy from vibrations and deformations; thermal devices aimed at pulling energy from temperature variations; radiant energy devices that capture energy from light, radio waves and other forms of radiation; and, electrochemical devices that tap biochemical reactions.

“Compared to the other approaches designed to harvest energy from human motion, our method has two fundamental advantages,” said Pint. “The materials are atomically thin and small enough to be impregnated into textiles without affecting the fabric’s look or feel and it can extract energy from movements that are slower than 10 Hertz–10 cycles per second–over the whole low-frequency window of movements corresponding to human motion.”

Doctoral students Nitin Muralidharan and Mengya Li co-led the effort to make and test the devices. “When you look at Usain Bolt, you see the fastest man on Earth. When I look at him, I see a machine working at 5 Hertz,” said Muralidharan.

Extracting usable energy from such low frequency motion has proven to be extremely challenging. For example, a number of research groups are developing energy harvesters based on piezoelectric materials that convert mechanical strain into electricity. However, these materials often work best at frequencies of more than 100 Hertz. This means that they don’t work for more than a tiny fraction of any human movement so they achieve limited efficiencies of less than 5-10 percent even under optimal conditions.

“Our harvester is calculated to operate at over 25 percent efficiency in an ideal device configuration, and most importantly harvest energy through the whole duration of even slow human motions, such as sitting or standing,” Pint said.

The Vanderbilt lab’s ultrathin energy harvester is based on the group’s research on advanced battery systems. Over the past 3 years, the team has explored the fundamental response of battery materials to bending and stretching. They were the first to demonstrate experimentally that the operating voltage changes when battery materials are placed under stress. Under tension, the voltage rises and under compression, it drops.

The team collaborated with Greg Walker, associate professor of mechanical engineering, who used computer models to validate these observations for lithium battery materials. Results of the study were published Jun. 27 in the journal ACS Nano in an article titled “The MechanoChemistry of Lithium Battery Electrodes.”

These observations led Pint’s team to reconstruct the battery with both positive and negative electrodes made from the same material. Although this prevents the device from storing energy, it allows it to fully exploit the voltage changes caused by bending and twisting and so produce significant amounts of electrical current in response to human motions.

The lab’s initial studies were published in 2016. They were further inspired by a parallel breakthrough by a group at Massachusetts Institute of Technology who produced a postage-stamp-sized device out of silicon and lithium that harvested energy via the effect Pint and his team were investigating.

In response, the Vanderbilt researchers decided to go as thin as possible by using black phosphorus nanosheets: A material has become the latest darling of the 2D materials research community because of its attractive electrical, optical and electrochemical properties.

Because the basic building blocks of the harvester are about 1/5000th the thickness of a human hair, the engineers can make their devices as thin or as thick as needed for specific applications. They have found that bending their prototype devices produces as much as 40 microwatts per square foot and can sustain current generation over the full duration of movements as slow as 0.01 Hertz, one cycle every 100 seconds.

The researchers acknowledge that one of the challenges they face is the relatively low voltage that their device produces. It’s in the millivolt range. However, they are applying their fundamental insights of the process to step up the voltage. They are also exploring the design of electrical components, like LCD displays, that operate at lower than normal voltages.

“One of the peer reviewers for our paper raised the question of safety,” Pint said. “That isn’t a problem here. Batteries usually catch on fire when the positive and negative electrodes are shorted, which ignites the electrolyte. Because our harvester has two identical electrodes, shorting it will do nothing more than inhibit the device from harvesting energy. It is true that our prototype will catch on fire if you put it under a blowtorch but we can eliminate even this concern by using a solid-state electrolyte.”

One of the more futuristic applications of this technology might be electrified clothing. It could power clothes impregnated with liquid crystal displays that allow wearers to change colors and patterns with a swipe on their smartphone. “We are already measuring performance within the ballpark for the power requirement for a medium-sized low-power LCD display when scaling the performance to thickness and areas of the clothes we wear.” Pint said.

Pint also believes there are potential applications for their device beyond power systems. “When incorporated into clothing, our device can translate human motion into an electrical signal with high sensitivity that could provide a historical record of our movements. Or clothes that track our motions in three dimensions could be integrated with virtual reality technology. There are many directions that this could go.”