Materials

New Quantum State Discovered in Trimer-Honeycomb Material

admin — Thu, 23 Feb 2023 22:56:55 +0000

New Quantum State Discovered in Trimer-Honeycomb Material admin Thu, 02/23/2023 - 17:56

A group of physicists, including two Georgia Tech researchers, have discovered a new quantum state. The study, published in the journal Nature, uncovered novel looping currents flowing along the edges of octahedral cells in a crystal of Mn3Si2Te6, which allowed for a billion percent increase in the material’s electric conductivity. The findings could lead to a new paradigm for quantum devices and superconductors.

The team consisted of Georgia Tech theoretical physicists Sami Hakani and Itamar Kimchi, along with experimental physicists Feng Ye (Oak Ridge National Lab), Lance DeLong (University of Kentucky), and, from the University of Colorado at Boulder: Gang Cao, Yifei Ni, Yu Zhang, and Hengdi Zhao. The group was drawn to the research after their previous study investigated the same material.

“Because this material did not fit any preexisting models, we had to develop new ideas to understand it,” said Georgia Tech graduate student Hakani, who played a key role in developing the theory. “These new ideas will help us study related materials that could be used for next-generation magnetic field devices.”

An Exception to the Rule

The physicists first became interested in the Mn3Si2Te6 material due to its unique electrical properties — in particular, a property called colossal magnetoresistance, an extreme enhancement in a material’s electrical conductivity when a magnetic field is applied.

In most materials, applying a magnetic field does not change that material’s conductivity. However, in another class of materials, applying a magnetic field does change conductivity; this is called magnetoresistance, and it can scale to “giant” and “colossal” changes in conductivity. In instances of colossal magnetoresistance, a material can change from behaving like an insulator (like Styrofoam) to being as conductive as a metal wire.

This change is not altogether unusual. Materials displaying giant magnetoresistance are not uncommon and are often used in computers; however, in all of these known materials, the material does not change its behavior in a way that significantly depends on the direction of the applied magnetic field. This new trimer-honeycomb material does.

“The phenomenon defies all existing theoretical models and experimental precedents,” said Kimchi, theoretical physicist and assistant professor in the School of Physics at Georgia Tech. And that’s where he and Hakani come in.

Uncovering Looping Currents

“As theoretical physicists, we develop new kinds of mathematical models,” said Kimchi. “When it’s qualitatively difficult to understand how anything can make sense in experimental data — when there’s something qualitatively shocking — we try to come up with that basic picture.”

Using the information uncovered by the experimental physicists, Hakani and Kimchi set out to understand why the extreme change in conductivity only happens when the magnetic field is applied perpendicularly to the honeycomb-like surface of the material.

“Our idea smelled promising, but, unfortunately, we quickly realized that currents between the magnetic manganese ions would be forbidden by symmetry, which was discouraging,” said Kimchi. “However, Sami then did the symmetry analysis for the octahedrally arranged tellurium ions, and, for them, currents were symmetry-allowed and could work out!”

Viewed from above, the material looks like a series of two-dimensional honeycombs. From the side, however, the material is composed of “sheets,” like a layer cake. Within each “sheet” of honeycomb, electrons can move in circular paths around each octahedral cell. These looping, circular-moving currents within the material are responsible for the material’s unique behavior.

On its own, without a magnetic field present, electrons move both counterclockwise and clockwise around the honeycomb “cells,” like cars going in both directions around a roundabout. Just like in uncontrolled traffic, “traffic jams” make it difficult for electrons to move quickly throughout the material. Without a way to streamline traffic, the material acts more like an insulator.

However, if a magnetic field is applied perpendicular to the honeycomb-like surface, a “flow of traffic” is established, and electrons navigate the loops more quickly. The material then acts as a conductor, showing a seven-magnitude increase in conductivity — equivalent to an increase of a billion percent.

A New Paradigm

The transformation from insulator to conductor can also be driven by applying electrical currents in the material, but in that case, it doesn’t happen instantaneously. It can take seconds or even minutes for the material to switch from insulator to conductor.

The team believes that this tunability and slower type of switching, coupled with the material’s sensitivity to currents, could lead to new applications and discoveries in current-controlled quantum devices, a field of devices that range from sensors to computers to secure communication.

The next step? Working to better understand the newly discovered quantum state, and finding other materials where the quantum state might exist.

“Looking forward, we hope to understand not only what makes this material special, but also which microscopic ingredients are needed for related materials to become useful quantum technologies in our future,” said Hakani.

Subtitle

The transformation allows for a billion percent increase in the material’s conductivity and could lead to a new paradigm for quantum devices.

Summary sentence

The transformation allows for a billion percent increase in the material’s conductivity and could lead to a new paradigm for quantum devices.

Summary

A group of physicists, including two Georgia Tech researchers, have discovered a new quantum state in trimer-honeycomb material. The transformation allows for a billion percent increase in the material’s conductivity and could lead to a new paradigm for quantum devices. The discovery builds on a previous study that first investigated the material, also known as Mn3Si2Te6, for its unusual and unique qualities.

Dateline

Thu, 02/23/2023 - 12:00

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By: Selena Langner
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Thu, 02/23/2023 - 17:17

Mark Prausnitz Elected to National Academy of Engineering

admin — Thu, 09 Feb 2023 19:52:53 +0000

Mark Prausnitz Elected to National Academy of Engineering admin Thu, 02/09/2023 - 14:52

Professor and entrepreneur Mark Prausnitz has been elected to the National Academy of Engineering (NAE), joining a membership that includes the nation’s most distinguished engineers. He is Georgia Tech’s 46th NAE member.

Prausnitz is the J. Erskine Love Jr. Chair of the School of Chemical and Biomolecular Engineering (ChBE) and director of Georgia Tech’s Center for Drug Design, Development and Delivery. He’s also the only Georgia Tech faculty member recognized as both a Regents’ Professor and Regents’ Entrepreneur, the highest academic titles awarded by the University System of Georgia Board of Regents. He joins 105 new NAE members in the 2023 class along with 18 new international members.

Read the full story on the College of Engineering website.

Summary sentence

The honor is one of the highest professional distinctions for engineers

Summary

The honor is one of the highest professional distinctions for engineers

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Tue, 02/07/2023 - 12:00

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Thu, 02/09/2023 - 14:18

Research Reveals Thermal Instability of Solar Cells but Offers a Bright Path Forward

admin — Thu, 09 Feb 2023 16:52:52 +0000

Research Reveals Thermal Instability of Solar Cells but Offers a Bright Path Forward admin Thu, 02/09/2023 - 11:52

A new type of solar technology has seemed promising in recent years. Halide perovskite solar cells are both high performing and low cost for producing electrical energy – two necessary ingredients for any successful solar technology of the future. But new solar cell materials should also match the stability of silicon-based solar cells, which boast more than 25 years of reliability.

In newly published research, a team led by Juan-Pablo Correa-Baena, assistant professor in the School of Materials Sciences and Engineering at Georgia Tech, shows that halide perovskite solar cells are less stable than previously thought. Their work reveals the thermal instability that happens within the cells’ interface layers, but also offers a path forward towards reliability and efficiency for halide perovskite solar technology. Their research, published as the cover story for the journal Advanced Materials in December 2022, has immediate implications for both academics and industry professionals working with perovskites in photovoltaics, a field concerned with electric currents generated by sunlight.

Lead halide perovskite solar cells promise superior conversion of sunlight into electrical power. Currently, the most common strategy for coaxing high conversion efficiency out of these cells is to treat their surfaces with large positively charged ions known as cations.

These cations are too big to fit into the perovskite atomic-scale lattice, and, upon landing on the perovskite crystal, change the material’s structure at the interface where they are deposited. The resulting atomic-scale defects limit the efficacy of current extraction from the solar cell. Despite awareness of these structural changes, research on whether the cations are stable after deposition is limited, leaving a gap in understanding of a process that could impact the long-term viability of halide perovskite solar cells.

“Our concern was that during long periods of solar cell operation the reconstruction of the interfaces would continue,” said Correa-Baena. “So, we sought to understand and demonstrate how this process happens over time.”

To carry out the experiment, the team created a sample solar device using typical perovskite films. The device features eight independent solar cells, which enables the researchers to experiment and generate data based on each cell’s performance. They investigated how the cells would perform, both with and without the cation surface treatment, and studied the cation-modified interfaces of each cell before and after prolonged thermal stress using synchrotron-based X-ray characterization techniques.

First, the researchers exposed the pre-treated samples to 100 degrees Celsius for 40 minutes, and then measured their changes in chemical composition using X-ray photoelectron spectroscopy. They also used another type of X-ray technology to investigate precisely what type of crystal structures form on the film’s surface. Combining the information from the two tools, the researchers could visualize how the cations diffuse into the lattice and how the interface structure changes when exposed to heat.

Next, to understand how the cation-induced structural changes impact solar cell performance, the researchers employed excitation correlation spectroscopy in collaboration with Carlos Silva, professor of physics and chemistry at Georgia Tech. The technique exposes the solar cell samples to very fast pulses of light and detects the intensity of light emitted from the film after each pulse to understand how energy from light is lost. The measurements allow the researchers to understand what kinds of surface defects are detrimental to performance.

Finally, the team correlated the changes in structure and optoelectronic properties with the differences in the solar cells’ efficiencies. They also studied the changes induced by high temperatures in two of the most used cations and observed the differences in dynamics at their interfaces.

“Our work revealed that there is concerning instability introduced by treatment with certain cations,” said Carlo Perini, a research scientist in Correa-Baena’s lab and the first author of the paper. “But the good news is that, with proper engineering of the interface layer, we will see enhanced stability of this technology in the future.”

The researchers learned that the surfaces of metal halide perovskite films treated with organic cations keep evolving in structure and composition under thermal stress. They saw that the resulting atomic-scale changes at the interface can cause a meaningful loss in power conversion efficiency in solar cells. In addition, they found that the speed of these changes depends on the type of cations used, suggesting that stable interfaces might be within reach with adequate engineering of the molecules.

“We hope this work will compel researchers to test these interfaces at high temperatures and seek solutions to the problem of instability,” Correa-Baena said. “This work should point scientists in the right direction, to an area where they can focus in order to build more efficient and stable solar technologies.”

CITATION: Perini, C. A. R., Rojas-Gatjens, E., Ravello, M., Castro-Mendez, A., Hidalgo, J., An, Y., Kim, S., Lai, B., Li, R., Silva-Acuña, C., Correa-Baena, J.-P., Interface Reconstruction from Ruddlesden–Popper Structures Impacts Stability in Lead Halide Perovskite Solar Cells. Adv. Mater. 2022, 34, 2204726.

DOI: https://doi.org/10.1002/adma.202204726

Summary sentence

Their work reveals what goes wrong within the cells’ interface layers.

Summary

Their work reveals what goes wrong within the cells’ interface layers.

Dateline

Thu, 02/09/2023 - 12:00

catherine.barzler@gatech.edu

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Thu, 02/09/2023 - 11:05

Researchers Chart Path to Cheaper Flexible Solar Cells

admin — Thu, 09 Feb 2023 03:46:02 +0000

Researchers Chart Path to Cheaper Flexible Solar Cells admin Wed, 02/08/2023 - 22:46

There’s a lot to like about perovskite-based solar cells. They are simple and cheap to produce, offer flexibility that could unlock a wide new range of installation methods and places, and in recent years have reached energy efficiencies approaching those of traditional silicon-based cells.

But figuring out how to produce perovskite-based energy devices that last longer than a couple of months has been a challenge.

Now researchers from Georgia Institute of Technology, University of California San Diego and Massachusetts Institute of Technology have reported new findings about perovskite solar cells that could lead the way to devices that perform better.

“Perovskite solar cells offer a lot of potential advantages because they are extremely lightweight and can be made with flexible plastic substrates,” said Juan-Pablo Correa-Baena, an assistant professor in the Georgia Tech School of Materials Science and Engineering. “To be able to compete in the marketplace with silicon-based solar cells, however, they need to be more efficient.”

In a study that was published February 8 in the journal Science and was sponsored by the U.S Department Energy and the National Science Foundation, the researchers described in greater detail the mechanisms of how adding alkali metal to the traditional perovskites leads to better performance.

“Perovskites could really change the game in solar,” said David Fenning, a professor of nanoengineering at the University of California San Diego. “They have the potential to reduce costs without giving up performance. But there’s still a lot to learn fundamentally about these materials.”

To understand perovskite crystals, it’s helpful to think of its crystalline structure as a triad. One part of the triad is typically formed from the element lead. The second is typically made up of an organic component such as methylammonium, and the third is often comprised of other halides such as bromine and iodine.

In recent years, researchers have focused on testing different recipes to achieve better efficiencies, such as adding iodine and bromine to the lead component of the structure. Later, they tried substituting cesium and rubidium to the part of the perovskite typically occupied by organic molecules.

“We knew from earlier work that adding cesium and rubidium to a mixed bromine and iodine lead perovskite leads to better stability and higher performance,” Correa-Baena said.

But little was known about why adding those alkali metals improved performance of the perovskites.

To understand exactly why that seemed to work, the researchers used high-intensity X-ray mapping to examine the perovskites at the nanoscale.

“By looking at the composition within the perovskite material, we can see how each individual element plays a role in improving the performance of the device,” said Yanqi (Grace) Luo, a nanoengineering PhD student at UC San Diego.

They discovered that when the cesium and rubidium were added to the mixed bromine and iodine lead perovskite, it caused the bromine and iodine to mix together more homogeneously, resulting in up to 2 percent higher conversion efficiency than the materials without these additives.

“We found that uniformity in the chemistry and structure is what helps a perovskite solar cell operate at its fullest potential,” Fenning said. “Any heterogeneity in that backbone is like a weak link in the chain.”

Even so, the researchers also observed that while adding rubidium or cesium caused the bromine and iodine to become more homogenous, the halide metals themselves within their own cation remained fairly clustered, creating inactive “dead zones” in the solar cell that produce no current.

“This was surprising,” Fenning said. “Having these dead zones would typically kill a solar cell. In other materials, they act like black holes that suck in electrons from other regions and never let them go, so you lose current and voltage.

“But in these perovskites, we saw that the dead zones around rubidium and cesium weren’t too detrimental to solar cell performance, though there was some current loss,” Fenning said. “This shows how robust these materials are but also that there’s even more opportunity for improvement.”

The findings add to the understanding of how the perovskite-based devices work at the nanoscale and could lay the groundwork for future improvements.

“These materials promise to be very cost effective and high performing, which is pretty much what we need to make sure photovoltaic panels are deployed widely,” Correa-Baena said. “We want to try to offset issues of climate change, so the idea is to have photovoltaic cells that are as cheap as possible.”

This research was supported by the U.S. Department of Energy EERE postdoctoral fellowship and grant Nos. DE-SC0001088 and DE-AC02-06CH11357, the California Energy Commission under grant No. EPC-16-050, the Skoltech NGP Program under grant No. 1913/R, the Hellman Fellowship and the National Science Foundation under grant Nos. CBET-1605495, DMR-1507803, GRFP 1122374, CHE-1338173 and ECCS-1542148. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsoring agencies.

CITATION: Juan-Pablo Correa-Baena, et al., “Homogenized halides and alkali cation segregation in alloyed organic-inorganic perovskites,” (Science, February 2019). http://dx.doi.org/10.1126/science.aah5065

Summary sentence

Researchers from Georgia Institute of Technology, University of California San Diego and Massachusetts Institute of Technology have reported new findings about perovskite solar cells that could lead the way to devices that perform better.

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Thu, 02/07/2019 - 12:00

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Tue, 01/07/2020 - 10:08

$2.3B Qcells Solar Power Investment Holds Major Potential for Georgia

admin — Mon, 23 Jan 2023 22:47:05 +0000

$2.3B Qcells Solar Power Investment Holds Major Potential for Georgia admin Mon, 01/23/2023 - 17:47

The state of Georgia is at the epicenter of what may be the largest investment in clean energy manufacturing in U.S. history, and Georgia Tech is poised to play a key role in an investment that is slated to create thousands of jobs and boost solar power infrastructure in our state and beyond.

Qcells, a solar power company, plans to build a $2.3 billion manufacturing complex just north of Atlanta in Cartersville to not only make state-of-the-art components for solar panels, but also to build complete panels used in a variety of settings, from houses to large-scale commercial and industrial solar arrays.

Georgia Tech is home to some of the world’s leading researchers and experts in photovoltaic materials and solar energy. Juan-Pablo Correa-Baena, assistant professor and Goizueta Junior Faculty Rotating Chair in the School of Materials Science and Engineering, and his research group have been blazing trails on the hunt for new materials that can be used in solar energy conversion.

“The most important part of this investment in U.S. manufacturing is the fact that Qcells is investing in the development of ingot and wafer production,” Correa-Baena said. Currently, silicon needs to be processed to form solar cells used to harvest energy. Ingots are the first step in the manufacturing process of refining raw materials into wafers. The wafers become the base for completed solar panels.

Over the past decade, most ingot and wafer production has been happening outside of the U.S. “With this investment, we guarantee that we can have full control of the supply chain by manufacturing all aspects of the solar panels domestically,” said Correa-Baena. Ultimately, the goal is to make solar energy more affordable for American consumers and create high-paying jobs for Georgians.

“It is exciting to see that silicon manufacturing is restarting in the U.S. and that Georgia is at the forefront of it,” said Ajeet Rohatgi, Regents’ Professor and John H. Weitnauer Jr. Chair in the School of Electrical and Computer Engineering.

Rohatgi is one of the world’s leading researchers in photovoltaics – the conversion of light into electricity using semiconducting materials like silicon. He is the founding director of the first university-based and Department of Energy-funded Center of Excellence for Photovoltaics Research and Education. The center’s work focuses on finding and improving the materials used to make solar cells while also improving their efficiency.

Qcells built its first plant near Dalton, Georgia, in 2019. By 2022, the facility had become the largest producer of solar panels in the western hemisphere. Rohatgi says representatives from Qcells have visited his research facilities on campus, and he and his team have visited the company’s Dalton facility as well.

“As demand for clean energy continues to grow nationally, we’re ready to put thousands of people to work creating fully American made and sustainable solar solutions, from raw material to finished panels,” said Justin Lee, CEO of Qcells. “We are committed to working with our customers as well as national and Georgia leaders to bring completely clean energy to millions of people across the country.”

Tim Lieuwen, executive director of the Strategic Energy Institute, Regents' Professor, and David S. Lewis Jr. Chair said, “Georgia Tech is a key leader in most of the core technologies associated with clean energy industries, has nationally distinctive researchers and facilities, and educates a lot of undergraduate and graduate students in these areas.”

That is why Tech has the potential to be a valuable partner in this project. “We are in a unique space where we can interface with Qcells to help them improve materials processing and explore new materials, but also aid in their manufacturing processes by introducing artificial intelligence to optimize processes and increase their productivity,” said Correa-Baena.

The announcement is not just significant for Georgia Tech, but for the state of Georgia as well. In Lieuwen’s view, Georgia is emerging as a center of clean energy manufacturing and technology, in no small part thanks to the Institute’s partnerships, research, and workforce development efforts. He says advancements in electric vehicles, batteries, and hydrogen power are all picking up steam in our state. “Having these types of companies in areas where Georgia Tech is focusing research and development efforts is good for the Institute and the state.”

The Qcells expansion is likely just the tip of the iceberg, as leading researchers from across campus identify projects like these where Tech ingenuity and innovation can make a difference.

“I’m enthusiastic about this expansion of solar cell manufacturing in Georgia because it builds on other clean energy, electrification, and energy storage industries already existing or planned for our state,” said Julia Kubanek, professor and vice president for Interdisciplinary Research. “The Southeast is increasingly becoming known as a hub for cleantech innovation, and Georgia Tech is proud to be a key contributor to this ecosystem.”

Production at the new Qcells solar plant is expected to start in 2024.

Summary sentence

Georgia Tech experts are at the forefront of technology and research that could revamp clean energy infrastructure in our state.

Summary

Georgia Tech experts are at the forefront of technology and research that could revamp clean energy infrastructure in our state.

Dateline

Mon, 01/23/2023 - 12:00

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Steven Norris
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Mon, 01/23/2023 - 17:27

Going Back to Basics Yields a Printable, Transparent Plastic That’s Highly Conductive

admin — Thu, 01 Dec 2022 19:21:14 +0000

Going Back to Basics Yields a Printable, Transparent Plastic That’s Highly Conductive admin Thu, 12/01/2022 - 14:21

It was a simple idea — maybe even too simple to work.

Research scientist James Ponder and a team of Georgia Tech chemists and engineers thought they could design a transparent polymer film that would conduct electricity as effectively as other commonly used materials, while also being flexible and easy to use at an industrial scale.

They’d do it by simply removing the nonconductive material from their conductive element. Sounds logical, right?

The resulting process could yield new kinds of flexible, transparent electronic devices — things like wearable biosensors, organic photovoltaic cells, and virtual or augmented reality displays and glasses.

“We had this initial idea that we have a conductive element that we're covering with a nonconductive material, so what if we just get rid of that,” said Ponder, who earned a Ph.D. in chemistry at Georgia Tech and returned as a research scientist in mechanical engineering. “It's a simple idea, and there were so many points where it could have failed for different reasons. But it does work, and it works better than we expected.”

Summary sentence

Chemists and engineers collaborate on process that washes away nonconductive side chains from a robust polymer backbone to create a powerful conductive plastic.

Summary

Chemists and engineers collaborate on process that washes away nonconductive side chains from a robust polymer backbone to create a powerful conductive plastic.

Dateline

Thu, 12/01/2022 - 12:00

jstewart@gatech.edu

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Joshua Stewart
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Atlanta, GA

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cos-quantum

conducting polymer

conductive

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Thu, 12/01/2022 - 11:35

Incoming First-Year Student is First Author of Published Paper

bwaye3 — Thu, 07 Jul 2022 18:10:33 +0000

Incoming First-Year Student is First Author of Published Paper bwaye3 Thu, 07/07/2022 - 14:10

Undergraduate engineering students interested in research typically enroll at Georgia Tech with an eye on joining a lab within its eight schools. Their long-term goal is to write and submit a study, hoping for an eventual publication in a peer-reviewed journal.

Rohan Datta, however, reversed the usual timeline. The 18-year-old recently graduated from The Galloway School in Atlanta. By the time he attends his first classes on campus this fall as a Stamps Scholar, Datta will already have a published paper on his resume.

With guidance from and collaboration with both a professor and an alumna of the School of Materials Science and Engineering (MSE), Datta is the first author on a recently published study in the Journal of Chemical Physics. In the paper, “Conductivity prediction model for ionic liquids using machine learning,” Datta describes his construction of a deep neural network capable of making rapid and accurate predictions of the conductivity of ionic liquids.

Datta’s publication marks a fitting conclusion to high school while serving as the next phase of his Georgia Tech experience.

Read the entire story.

Subtitle

Recent high school graduate Rohan Datta published his Georgia Tech research in the Journal of Chemical Physics

Summary sentence

Recent high school graduate Rohan Datta published his Georgia Tech research in the Journal of Chemical Physics.

Summary

Recent high school graduate Rohan Datta published his Georgia Tech research in the Journal of Chemical Physics. After working virtually in a Georgia Tech lab the last two years, he'll enter Georgia Tech as a freshman this coming fall.

Dateline

Wed, 07/06/2022 - 12:00

maderer@gatech.edu

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Jason Maderer
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Wed, 07/06/2022 - 11:49

The Future of 5G+ Infrastructure Could be Built Tile by Tile

bwaye3 — Mon, 04 Apr 2022 15:15:28 +0000

The Future of 5G+ Infrastructure Could be Built Tile by Tile bwaye3 Mon, 04/04/2022 - 11:15

5G+ (5G/Beyond 5G) is the fastest-growing segment and the only significant opportunity for investment growth in the wireless network infrastructure market, according to the latest forecast by Gartner, Inc. But currently 5G+ technologies rely on large antenna arrays that are typically bulky and come only in very limited sizes, making them difficult to transport and expensive to customize.

Researchers from Georgia Tech’s College of Engineering have developed a novel and flexible solution to address the problem. Their additively manufactured tile-based approach can construct on-demand, massively scalable arrays of 5G+ (5G/Beyond 5G)‐enabled smart skins with the potential to enable intelligence on nearly any surface or object. The study, recently published in Scientific Reports, describes the approach, which is not only much easier to scale and customize than current practices, but features no performance degradation whenever flexed or scaled to a very large number of tiles.

“Typically, there are a lot of smaller wireless network systems working together, but they are not scalable. With the current techniques, you can’t increase, decrease, or direct bandwidth, especially for very large areas,” said Manos Tentzeris, Ken Byers Professor in Flexible Electronics in the School of Electrical and Computer Engineering. “Being able to utilize and scale this novel tile-based approach makes this possible.”

Tentzeris says his team’s modular application equipped with 5G+ capability has the potential for immediate, large-scale impact as the telecommunications industry continues to rapidly transition to standards for faster, higher capacity, and lower latency communications.

BUILDING THE TILES

In Georgia Tech’s new approach, flexible and additively manufactured tiles are assembled onto a single, flexible underlying layer. This allows tile arrays to be attached to a multitude of surfaces. The architecture also allows for very large 5G+ phased/electronically steerable antenna array networks to be installed on-the-fly. According to Tentzeris, attaching a tile array to an unmanned aerial vehicle (UAV) is even a possibility to surge broadband capacity in low coverage areas.

In the study, the team fabricated a proof-of-concept, flexible 5×5-centimeter tile array and wrapped it around a 3.5-centimeter radius curvature. Each tile includes an antenna subarray and an integrated, beamforming integrated circuit on an underlying tiling layer to create a smart skin that can seamlessly interconnect the tiles into very large antenna arrays and massive multiple-input multiple-outputs (MIMOs) — the practice of housing two or more antennas within a single wireless device. Tile-based array architectures on rigid surfaces with single antenna elements have been researched before, but do not include the modularity, additive manufacturability, or flexible implementation of the Georgia Tech design.

The proposed modular tile approach means tiles of identical sizes can be manufactured in large quantities and are easily replaceable, reducing the cost of customization and repairs. Essentially, this approach combines removable elements, modularity, massive scalability, low cost, and flexibility into one system.

5G+ IS JUST THE BEGINNING

While the tiling architecture has demonstrated the ability to greatly enhance 5G+ technologies, its combination of flexible and conformal capabilities has the potential to be applied in numerous different environments, the Georgia Tech team says.

“The shape and features of each tile scale can be singular and can accommodate different frequency bands and power levels,” said Tentzeris. “One could have communications capabilities, another sensing capabilities, and another could be an energy harvester tile for solar, thermal, or ambient RF energy. The application of the tile framework is not limited to communications.”

Internet of Things, virtual reality, as well as smart manufacturing/Industry 4.0 — a technology-driven approach that utilizes internet-connected “intelligent” machinery to monitor and fully automate the production process — are additional areas of application the team is excited to explore.

“The tile-architecture’s mass scalability makes its applications particularly diverse and virtually ubiquitous. From structures the size of dams and buildings, to machinery or cars, down to individual health-monitoring wearables,” said Tentzeris. “We’re moving in a direction where everything will be covered in some type of a wireless conformal smart skin encompassing electronically steerable antenna arrays of widely diverse sizes that will allow for effective monitoring.”

The team now looks forward to testing the approach outside the lab on large, real-world structures. They are currently working on the fabrication of much larger, fully inkjet-printed tile arrays (256+ elements) that will be presented at the upcoming International Microwave Symposium (IEEE IMS 2022) – the flagship IEEE conference in RF and microwave engineering. The IMS presentation will introduce a new tile-based large-area architecture version that will allow assembly of customizable tile arrays in a rapid and low-cost fashion for numerous conformal platforms and 5G+ enabled applications.

****

The authors declare no competing interests.

This work was supported in part by the National Science Foundation.

CITATIONS: He, X., Cui, Y. & Tentzeris, M.M. Tile-based massively scalable MIMO and phased arrays for 5G/B5G-enabled smart skins and reconfigurable intelligent surfaces. Sci Rep 12, 2741 (2022). https://doi.org/10.1038/s41598-022-06096-9

K.Hu, G.S.V.Angulo, Y.Cui and M.M.Tentzeris, “Flexible and Scalable Additively Manufactured Tile-Based Phased Arrays for Satellite Communications and 5G mmWave Applications,” accepted for presentation at IEEE International Microwave Symposium (IMS) 2022, Denver, CO, June 2022.

Summary sentence

Manos Tentzeris and his team of Georgia Tech researchers flex their novel 5G+‐enabled massively scalable tile arrays

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Tue, 03/29/2022 - 12:00

dwatson@ece.gatech.edu

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Fri, 04/01/2022 - 15:17

$40 Million NASA Award to Increase Rotorcraft Vertical Lift Technology at Georgia Tech

bwaye3 — Mon, 14 Feb 2022 22:10:24 +0000

$40 Million NASA Award to Increase Rotorcraft Vertical Lift Technology at Georgia Tech bwaye3 Mon, 02/14/2022 - 17:10

A new award from NASA will give Georgia Tech researchers easier and faster access to research and engineering funds during the next five years to support advances in rotorcraft vertical lift technology. The team, led by Professor Marilyn Smith, is one of six chosen by NASA and the only higher education institution selected as a leader.

Georgia Tech will provide resources and technical expertise to support the Rotorcraft Vertical Lift Technology Development through task orders in areas such as advanced rotorcraft technologies, testing, flight controls, and health management. Most of the work will be performed on campus, with some taking place at NASA’s Ames Research Center in California.

The Rotorcraft Vertical Lift Technology Development (RVLTD) award is an IDIQ (Indefinite Delivery/Indefinite Quantity) contract with a total ceiling of $40 million. It allows Georgia Tech to propose, apply, and quickly learn if they’re selected for NASA research projects that could also include developing codes, accessing models for validation, and more.

“Instead of writing a 30-page research proposal and waiting up to year for a decision, this contract vehicle allows us to submit a brief statement of work in response to NASA’s requests for support. We will learn within a few weeks if NASA selects our team for each request,” said Smith, a faculty member in Daniel Guggenheim School of Aerospace Engineering (AE School). “It’s a significant advantage that allows us to collaborate closer with NASA.”

The Georgia Tech group includes GTRI (Georgia Tech Research Institute) and the University of Texas at Arlington. It also includes a number of private companies around the country, with an emphasis on small businesses and organizations led by veterans and women. One of them is Laser Aviation in Duluth, Georgia, which specializes in 3D laser scanning and modeling.

Of the six submissions accepted, Georgia Tech’s proposal was ranked first by the Source Evaluation Board (SEB).

The AE School was one of the nation’s first helicopter rotorcraft research and educational institution. Montgomery Knight became the School’s first director in 1942 and developed one of the first jet-powered rotors for a helicopter. He was among the country’s earliest top researchers of helicopter design.

Through the decades, Georgia Tech has expanded its research to fit the current definition of rotorcraft, which also includes tilt rotors, unmanned air vehicles, and advanced urban air mobility. Georgia Tech has been a Vertical Lift Research Center of Excellence (VLRCOE) since 1982, conducting basic research focused on scientific barriers in technologies that support current and future vertical lift capabilities.

The RVLTD award is not restricted to AE researchers. Any Georgia Tech faculty member supporting vertical lift technology can ask to be on the list of faculty who will respond to each NASA request. Those interested should send their contact details and research areas of interest to Smith.

“Georgia Tech faculty and students are contributing to rotorcraft technology research in a variety of ways,” said Smith, who serves as director of the VLRCOE, which receives funding from the U.S. Army, U.S. Navy, and NASA. “This includes not only vehicle design and analysis in AE, but air traffic control, cyber-physical security, vertiport design, public policy, robotics and sustainability. We have the core faculty and students across the Institute to drive this field. This depth of research, along with our excellent student base, is what makes us more competitive.”

Summary sentence

A new NASA award gives Georgia Tech easier and faster access to funds for supporting advances in rotorcraft vertical lift technology.

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Wed, 02/02/2022 - 12:00

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Fri, 02/04/2022 - 11:45

Researchers Develop Methodology for Streamlined Control of Material Deformation

bwaye3 — Mon, 14 Feb 2022 22:10:24 +0000

Researchers Develop Methodology for Streamlined Control of Material Deformation bwaye3 Mon, 02/14/2022 - 17:10

Can you crumple up two sheets of paper the exact same way? Probably not — the very flexibility that lets flexible structures from paper to biopolymers and membranes undergo many types of large deformations makes them notoriously difficult to control. Researchers from the Georgia Institute of Technology, Universiteit van Amsterdam, and Universiteit Leiden have shed new light on this fundamental challenge, demonstrating that new physical theories provide precise predictions of the deformations of certain structures, as recently published in Nature Communications.

In the paper, Michael Czajkowski and D. Zeb Rocklin from Georgia Tech, Corentin Coulais from Universiteit van Amsterdam, and Martin van Hecke of AMOLF and Universiteit Leiden approach a highly studied exotic elastic material, uncover an intuitive geometrical description of the pronounced – or nonlinear – soft deformations, and show how to activate any of these deformations on-demand with minimal inputs. This new theory reveals that a flexible mechanical structure is governed by some of the same math as electromagnetic waves, phase transitions, and even black holes.

“So many other systems struggle with how to be strong and solid in some ways but flexible and compliant in others, from the human body and micro-organisms to clothing and industrial robots,” said Rocklin. “These structures solve that problem in an incredibly elegant way that permits a single folding mechanism to generate a wide family of deformations. We’ve shown that a single folding mode can transform a structure into an infinite family of shapes.”

A Brief History of Metamaterials

Metamaterials rely on the use of hinges, folds, cuts, and “flexible” ingredients to display the variety of counterintuitive physics that has been steadily revealed over the past decade of intense research. Many of these new behaviors have emerged from the development of auxetics, materials that tend to shrink in all directions when they are compressed from any direction rather than bulging outward. Although the researchers’ chosen structure, “Rotating Squares,” is already one of the most heavily researched metamaterials, they uncovered entirely new and powerful physics hiding within its deformations.

“Normally complex real-world structures defy analytical physics, which made it all the more thrilling when Michael found that his conformal predictions could account for 99.9% of the variance in Corentin’s structure,” said Rocklin. “This new approach could allow us to predict and control tough, flexible structures from the size of skyscrapers to the microscale.”

Conformal Findings

The results of this paper rely on the novel observation that these maximally auxetic metamaterials deform conformally, which the researchers confirmed with a high degree of accuracy. This means that any angle drawn on the material before and after deformation will still look like the same angle. This seemingly mundane observation activates powerful mathematical structures.

This conformal insight allows for a variety of pen-and-paper analytic advances: a nonlinear energy functional, deformation fitting methods, new prediction methods etc. This culminates with a recipe to choose any of these conformal deformations in an exact, reversible, and mathematically straightforward manner via the manipulation of the boundary. By choosing how much the boundary is stretched, the overall shape can be picked from infinite possibilities.

Such deformation control is still limited by the essential nature of conformal deformations. However, the underlying principles are quite general, and researchers are working to apply these new principles to more varied and complex structures.

"Our results are very promising for the soft microscopic robotics that are being developed for non-invasive surgical purposes," said Czajkowski. "In this effort, scalability and precise external control are two of the primary goalposts, and our style of deformation control seems perfectly suited for the job."

The jump to more provocative applications is likely not far off, as the realm of metamaterials has steadily become populated with manipulatable faces, a variety of new grabbers and hands, and even an elastic worm that can thread a series of needles. These advances will become essential in the effort to develop soft microscopic robots, which must be externally manipulated to move through a body and perform noninvasive surgeries.

Citation:

Michael Czajkowski, Corentin Coulais, Martin van Hecke and D. Zeb Rocklin, “Conformal elasticity of mechanism-based metamaterials,” Nature Communications (January 11, 2022). doi.org/10.1038/s41467-021-27825-0

Summary sentence

Researchers demonstrate that new physical theories provide precise predictions of the deformations of certain structures, revealing that a flexible mechanical structure is governed by some of the same math as electromagnetic waves and even black holes.

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Fri, 02/04/2022 - 12:00

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Georgia Parmelee | georgia.parmelee@gatech.edu

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Wed, 02/09/2022 - 14:47