Category Archives: Materials

A further step has been taken along the road to manufacturing solar cells from lead-free perovskites. High quality films based on double perovskites, which show promising photovoltaic properties, have been developed in collaboration between Linköping University, Sweden, and Nanyang Technological University in Singapore.

The lead-free double perovskite solar cells (yellow, in the front) compared with the lead-based device (dark, in the background). The next step is tune the color of the double perovskites into dark, so that they can absorb more light for efficient solar cells. Credit: Thor Balkhed

The lead-free double perovskite solar cells (yellow, in the front) compared with the lead-based device (dark, in the background). The next step is tune the color of the double perovskites into dark, so that they can absorb more light for efficient solar cells. Credit: Thor Balkhed

Research groups around the world have recognised the potential of perovskites as one of the most promising materials for the development of cheap, environmentally friendly and efficient solar cells. In just a few years, the power conversion efficiency has increased from a few percent to over 22%. The perovskites currently available for use in solar cells, however, contain lead, and Feng Gao, senior lecturer at LiU, was appointed in the autumn of 2017 as Wallenberg Academy Fellow to develop lead-free double perovskites, in which a monovalent metal and a trivalent metal replace the divalent lead.

In the laboratory at the Division of Biomolecular and Organic Electronics, LiU, postdoc researchers Weihua Ning and Feng Wang have successfully manufactured single-layer thin films of densely packed crystals of double perovskites. The films are of extremely high quality and can be used as the active layer in solar cells, in which sunlight is absorbed and charge carriers created.

“Our colleagues at Nanyang Technological University in Singapore have shown that the charge carriers demonstrate long diffusion lengths in the material, which is necessary if the material is to be appropriate for application in solar cells,” says Feng Gao.

The power conversion efficiency of the solar cells is still low – only around 1% of the energy in sunlight is converted to electricity – but neither Feng Gao or Weihua Ning are worried.

“No, we have taken the first major step and developed a method to manufacture the active layer. We have several good ideas of how to proceed to increase the efficiency in the near future,” says Feng Gao.

Weihua Ning nods in agreement.

Researchers have calculated that over 4,000 different combinations of materials can form double perovskites. They will also use theoretical calculations to identify the combinations that are most suitable for use in solar cells.

This breakthrough for research in double perovskites is also a result of the joint PhD programme in Materials- and nanoscience/technology at Linköping University and Nanyang Technological University.

“This publication is a spin-off of the discussions in relation to the joint PhD programme between NTU-LiU. Two PhD students, one on each side, have been recruited to work on this project. This is an excellent start for the program.” says Professor Tze Chien Sum from NTU.

“We complement each other very well, the group led by Professor Sum in NTU are experts in photophysics and we are experts in materials science and device physics,” says Feng Gao.

Tre results is published in the prestigious scientific journal Advanced Materials.

AKHAN Semiconductor, a technology company specializing in the fabrication and application of lab-grown, electronics-grade diamonds, announced today that it has obtained official notifications from both the United States Patent and Trademark Office (USPTO) and Taiwan Intellectual Property Office (TIPO) for the Miraj Diamond trademark registration and patent allowance.

The official registration of the Miraj Diamond mark by the USPTO (Registration No. 5,438,740) follows nearly six years of completed filings fulfilled by the Illinois-based technology company following its launch in December 2012. The TIPO issued patent I615943 is the second AKHAN patent to be granted by the country– well-known to be strategic in the global semiconductor marketplace. The patent is a foreign counterpart of other issued and pending patents owned by AKHAN Semiconductor, Inc. that are used in the company’s Miraj Diamond® products. The claims protect uses far beyond the existing applications, including microprocessor applications. Covering the base materials common to nearly all semiconductor components, the intellectual property can be realized in everything from diodes, transistors, and power inverters, to fully functioning diamond chips such as integrated circuitry.

“The official declarations from both the USPTO and TIPO significantly add to the critical protections of the Miraj Diamond intellectual property portfolio and brand,” said Adam Khan, Founder & Chief Executive Officer of AKHAN Semiconductor. “Less than six years after our founding, the Miraj Diamond trademark is not only gaining global attention from the consumer electronics and semiconductor market places, but is also synonymous for next-generation performance, breakthrough capability, and flagship technology with diamond.”

“The notices of these issuances are very timely as we complete the construction of our cleanroom pilot production facility in northern Illinois,” added Carl Shurboff, AKHAN President and Chief Operating Officer. “With the targeted 2019 launch of our Miraj Diamond® Glass products for Smartphone devices and the concurrent development of our Miraj Diamond® electronics products for aerospace and defense, the brand equity we deliver in diamond continues unparalleled.”

“Safeguarding the technology and trademark from infringement, improper use, and other challenges, benefits not only our OEM Customers, by preserving their market value and time-based exclusivity, but also our shareholders, corporate development partners, and technology partners around the world,” said company Sales Advisor to the Board, Jeffrey G. Miller.

Silicon solar cells dominate the global photovoltaic market today with a share of 90 percent. With ever new technological developments, research and industry are nearing the theoretical efficiency limit for semiconductor silicon. At the same time, they are forging new paths to develop a new generation of even more efficient solar cells.

The Fraunhofer researchers achieved the high conversion efficiency of the silicon-based multi-junction solar cell with extremely thin 0.002 mm semiconductor layers of III-V compound semiconductors, bonding them to a silicon solar cell. To compare, the thickness of these layers is less than one twentieth the thickness of a human hair. The visible sunlight is absorbed in a gallium-indium-phosphide (GaInP) top cell, the near infrared light in gallium-arsenide (GaAs) and the longer wavelengths in the silicon subcell. In this way, the efficiency of silicon solar cells can be significantly increased.

Silicon-based multi-junction solar cell consisting of III-V semiconductors and silicon. The record cell converts 33.3 percent of the incident sunlight into electricity.  © Fraunhofer ISE/Photo: Dirk Mahler

Silicon-based multi-junction solar cell consisting of III-V semiconductors and silicon. The record cell converts 33.3 percent of the incident sunlight into electricity.
© Fraunhofer ISE/Photo: Dirk Mahler

“Photovoltaics is a key pillar for the energy transformation,” says Dr. Andreas Bett, Institute Director of Fraunhofer ISE. “Meanwhile, the costs have decreased to such an extent that photovoltaics has become an economically viable competitor to conventional energy sources. This development, however, is not over yet. The new result shows how material consumption can be reduced through higher efficiencies, so that not only the costs of photovoltaics can be further optimized but also its manufacture can be carried out in a resource-friendly manner.

Already in November 2016, the solar researchers in Freiburg together with their industry partner EVG demonstrated an efficiency of 30.2 percent, increasing it to 31.3 percent in March 2017. Now they have succeeded once again in greatly improving the light absorption and the charge separation in silicon, thus achieving a new record of 33.3 percent efficiency. The technology also convinced the jury of the GreenTec Awards 2018 and has been nominated among the top three in the category “Energy.”

The Technology

For this achievement, the researchers used a well-known process from the microelectronics industry called “direct wafer bonding” to transfer III-V semiconductor layers, of only 1.9 micrometers thick, to silicon. The surfaces were deoxidized in a EVG580® ComBond® chamber under high vacuum with a ion beam and subsequently bonded together under pressure. The atoms on the surface of the III-V subcell form bonds with the silicon atoms, creating a monolithic device. The complexity of its inner structure is not evident from its outer appearance: the cell has a simple front and rear contact just as a conventional silicon solar cell and therefore can be integrated into photovoltaic modules in the same manner.

EVG ComBond automated high-vacuum wafer bonding platform  (Photo courtesy of EV Group).

EVG ComBond automated high-vacuum wafer bonding platform
(Photo courtesy of EV Group).

The III-V / Si multi-junction solar cell consists of a sequence of subcells stacked on top of each other. So-called “tunnel diodes” internally connect the three subcells made of gallium-indium-phosphide (GaInP), gallium-arsenide (GaAs) and silicon (Si), which span the absorption range of the sun’s spectrum. The GaInP top cell absorbs radiation between 300 and 670 nm. The middle GaAs subcell absorbs radiation between 500 and 890 nm and the bottom Si subcell between 650 and 1180 nm, respectively. The III-V layers are first epitaxially deposited on a GaAs substrate and then bonded to a silicon solar cell structure. Here a tunnel oxide passivated contact (TOPCon) is applied to the front and back surfaces of the silicon. Subsequently the GaAs substrate is removed, a nanostructured backside contact is implemented to prolong the path length of light. A front side contact grid and antireflection coating are also applied.

On the way to the industrial manufacturing of III-V / Si multi-junction solar cells, the costs of the III-V epitaxy and the connecting technology with silicon must be reduced. There are still great challenges to overcome in this area, which the Fraunhofer ISE researchers intend to solve through future investigations. Fraunhofer ISE’s new Center for High Efficiency Solar Cells, presently being constructed in Freiburg, will provide them with the perfect setting for developing next-generation III-V and silicon solar cell technologies. The ultimate objective is to make high efficiency solar PV modules with efficiencies of over 30 percent possible in the future.

Project Financing

Dr. Roman Cariou, the young scientist and first author, was supported through the European Union with a Marie Curie Stipendium (HISTORIC, 655272). The work was also supported by the European Union within the NanoTandem project (641023) as well as by the German Federal Ministry for Economic Affairs and Energy BMWi in the PoTaSi project (FKZ 0324247).

Correction: A previous version of this article incorrectly state “imec” in the headline, instead of Fraunhofer ISE. Solid State Technology regrets the error.

Graphene is a two-dimensional nanocarbon material, having unique properties in electronic, optical and thermal properties, which can be applied for optoelectronic devices. Graphene-based blackbody emitters are also promising light emitters on silicon chip in NIR and mid-infrared region. However, although graphene-based blackbody emitters have been demonstrated under steady-state conditions or relatively slow modulation (100 kHz), the transient properties of these emitters under high-speed modulation have not been reported to date. Also, the optical communications with graphene-based emitters have never been demonstrated.

Square graphene sheet is connected to source and drain electrodes. Modulated blackbody emission is obtained from graphene by applying input signal. Credit: Keio University

Square graphene sheet is connected to source and drain electrodes. Modulated blackbody emission is obtained from graphene by applying input signal. Credit: Keio University

Here, a highly integrated, high-speed and on-chip blackbody emitter based on graphene in NIR region including telecommunication wavelength was demonstrated. A fast response time of ~ 100 ps, which is ~ 105 higher than the previous graphene emitters, has been experimentally demonstrated for single and few-layer graphene, the emission responses can be controlled by the graphene contact with the substrate depending on the number of graphene layers. The mechanisms of the high-speed emission are elucidated by performing theoretical calculations of the heat conduction equations considering the thermal model of emitters including graphene and a substrate. The simulated results indicate that the fast response properties can be understood not only by the classical thermal transport of in-plane heat conduction in graphene and heat dissipation to the substrate but also by the remote quantum thermal transport via the surface polar phonons (SPoPhs) of the substrates. In addition, first real-time optical communication with graphene-based light emitters was experimentally demonstrated, indicating that graphene emitters are novel light sources for optical communication. Furthermore, we fabricated integrated two-dimensional array emitters with large-scale graphene grown by chemical vapour deposition (CVD) method and capped emitters operable in air, and carried out the direct coupling of optical fibers to the emitters owing to their small footprint and planar device structure.

Graphene light emitters are greatly advantageous over conventional compound semiconductor emitters because they can be highly integrated on silicon chip due to simple fabrication processes of graphene emitters and direct coupling with silicon waveguide through an evanescent field. Because graphene can realize high-speed, small footprint and on-Si-chip light emitters, which are still challenges for compound semiconductors, the graphene-based light emitters can open new routes to highly integrated optoelectronics and silicon photonics.

Following three years of extensive research, Hebrew University of Jerusalem (HU) physicist Dr. Uriel Levy and his team have created technology that will enable our computers–and all optic communication devices–to run 100 times faster through terahertz microchips.

Until now, two major challenges stood in the way of creating the terahertz microchip: overheating and scalability.

However, in a paper published this week in Laser and Photonics Review, Dr. Levy, head of HU’s Nano-Opto Group and HU emeritus professor Joseph Shappir have shown proof of concept for an optic technology that integrates the speed of optic (light) communications with the reliability–and manufacturing scalability–of electronics.

Optic communications encompass all technologies that use light and transmit through fiber optic cables, such as the internet, email, text messages, phone calls, the cloud and data centers, among others. Optic communications are super fast but in microchips they become unreliable and difficult to replicate in large quanitites.

Now, by using a Metal-Oxide-Nitride-Oxide-Silicon (MONOS) structure, Levy and his team have come up with a new integrated circuit that uses flash memory technology–the kind used in flash drives and discs-on-key–in microchips. If successful, this technology will enable standard 8-16 gigahertz computers to run 100 times faster and will bring all optic devices closer to the holy grail of communications: the terahertz chip.

As Dr. Uriel Levy shared, “this discovery could help fill the ‘THz gap’ and create new and more powerful wireless devices that could transmit data at significantly higher speeds than currently possible. In the world of hi-tech advances, this is game-changing technology,”

Meir Grajower, the leading HU PhD student on the project, added, “It will now be possible to manufacture any optical device with the precision and cost-effectiveness of flash technology”.

Coming soon to a chip near you…

Single crystal tin selenide (SnSe) is a semiconductor and an ideal thermoelectric material; it can directly convert waste heat to electrical energy or be used for cooling. When a group of researchers from Case Western Reserve University in Cleveland, Ohio, saw the graphene-like layered crystal structure of SnSe, they had one of those magical “aha!” moments.

Electric charges in a nanostructured tin selenide (SnSe) thin film flow from the hot end to the cold end of the material and generate a voltage. Credit: Xuan Gao

Electric charges in a nanostructured tin selenide (SnSe) thin film flow from the hot end to the cold end of the material and generate a voltage. Credit: Xuan Gao

The group reports in the Journal of Applied Physics, from AIP Publishing, that they immediately recognized this material’s potential to be fabricated in nanostructure forms. “Our lab has been working on two-dimensional semiconductors with layered structures similar to graphene,” said Xuan Gao, an associate professor at Case Western.

Nanomaterials with nanometer-scale dimensions — such as thickness and grain size — have favorable thermoelectric properties. This inspired the researchers to grow nanometer-thick nanoflakes and thin films of SnSe to further study its thermoelectric properties.

The group’s work centers on the thermoelectric effect. They study how the temperature difference in a material can cause charge carriers — electrons or holes — to redistribute and generate a voltage across the material, converting thermal energy into electricity.

“Applying a voltage on a thermoelectric material can also lead to a temperature gradient, which means you can use thermoelectric materials for cooling,” said Gao. “Generally, materials with a high figure of merit have high electrical conductivity, a high Seebeck coefficient — generated voltage per Kelvin of temperature difference within a material — and low thermal conductivity,” he said.

A thermoelectric figure of merit, ZT, indicates how efficiently a material converts thermal energy to electrical energy. The group’s work focuses on the power factor, which is proportional to ZT and indicates a material’s ability to convert energy, so they measured the power factor of the materials they made.

To grow SnSe nanostructures, they used a chemical vapor deposition (CVD) process. They thermally evaporated a tin selenide powder source inside an evacuated quartz tube. Tin and selenium atoms react on a silicon or mica growth wafer placed at the low-temperature zone of the quartz tube. This causes SnSe nanoflakes to form on the surface of the wafer. Adding a dopant element like silver to SnSe thin films during material synthesis can further optimize its thermoelectric properties.

At the start, “the nanostructure SnSe thin films we fabricated had a power factor of only ~5 percent of that of single crystal SnSe at room temperature,” said Shuhao Liu, an author on the paper. But, after trying a variety of dopants to improve the material’s power factor, they determined that “silver was the most effective — resulting in a 300 percent power factor improvement compared to undoped samples,” Liu said. “The silver-doped SnSe nanostructured thin film holds promise for a high figure of merit.”

In the future, the researcher hope that SnSe nanostructures and thin films may be useful for miniaturized, environmentally friendly, low-cost thermoelectric and cooling devices.

Thousands of miles of fiber-optic cables crisscross the globe and package everything from financial data to cat videos into light. But when the signal arrives at your local data center, it runs into a silicon bottleneck. Instead of light, computers run on electrons moving through silicon-based chips — which, despite huge advances, are still less efficient than photonics.

To break through this bottleneck, researchers are trying to integrate photonics into silicon devices. They’ve been developing lasers — a crucial component of photonic circuits — that work seamlessly on silicon. In a paper appearing this week in APL Photonics, from AIP Publishing, researchers from the University of California, Santa Barbara write that the future of silicon-based lasers may be in tiny, atomlike structures called quantum dots.

Such lasers could save a lot of energy. Replacing the electronic components that connect devices with photonic components could cut energy use by 20 to 75 percent, Justin Norman, a graduate student at UC Santa Barbara, said. “It’s a substantial cut to global energy consumption just by having a way to integrate lasers and photonic circuits with silicon.”

Silicon, however, does not have the right properties for lasers. Researchers have instead turned to a class of materials from Groups III and V of the periodic table because these materials can be integrated with silicon.

Initially, the researchers struggled to find a functional integration method, but ultimately ended up using quantum dots because they can be grown directly on silicon, Norman said. Quantum dots are semiconductor particles only a few nanometers wide — small enough that they behave like individual atoms. When driven with electrical current, electrons and positively charged holes become confined in the dots and recombine to emit light — a property that can be exploited to make lasers.

The researchers made their III-V quantum-dot lasers using a technique called molecular beam epitaxy. They deposit the III-V material onto the silicon substrate, and its atoms self-assemble into a crystalline structure. But the crystal structure of silicon differs from III-V materials, leading to defects that allow electrons and holes to escape, degrading performance. Fortunately, because quantum dots are packed together at high densities — more than 50 billion dots per square centimeter — they capture electrons and holes before the particles are lost.

These lasers have many other advantages, Norman said. For example, quantum dots are more stable in photonic circuits because they have localized atomlike energy states. They can also run on less power because they don’t need as much electric current. Moreover, they can operate at higher temperatures and be scaled down to smaller sizes.

In just the last year, researchers have made considerable progress thanks to advances in material growth, Norman said. Now, the lasers operate at 35 degrees Celsius without much degradation and the researchers report that the lifetime could be up to 10 million hours.

They are now testing lasers that can operate at 60 to 80 degrees Celsius, the more typical temperature range of a data center or supercomputer. They’re also working on designing epitaxial waveguides and other photonic components, Norman said. “Suddenly,” he said, “we’ve made so much progress that things are looking a little more near term.”

Veeco Instruments Inc. (NASDAQ: VECO) today announced it has completed installation of its 100th automated Molecular Beam Epitaxy (MBE) system. The installation of Veeco’s GEN10™ MBE System last month at Silanna Semiconductor PTY Ltd. in Australia marks this significant company milestone. The company also operates a Veeco Dual GEN200® MBE System for production of advanced nitride compound semiconductor devices including ultraviolet light emitting diodes (UV-LEDs).

“Veeco has earned a reputation for consistently developing innovative and reliable MBE technology from research scale to production,” said Petar Atanackovic, Ph.D., chief scientist of Silanna Semiconductor PTY Ltd. “The flexibility and deposition capability of the GEN10 system will enable us to develop new materials at the atomic level allowing us to exploit new quantum properties. Veeco’s technology portfolio and leadership in MBE systems provides us with a clear path to easily scale to volume production in the future.”

Silanna is using the GEN10 system for advanced oxide research and development (R&D) for optoelectronic devices. The GEN10 is built upon almost 20 years of cumulative automation knowledge and derived from the company’s proven production MBE systems. Adopted by numerous leading corporations, institutions and universities for all major MBE applications, many customers choose the GEN10 because of its flexibility, which allows them to configure the system based on their application. This gives customers optimal performance with any material set, including those related to III-V group elements, oxides and nitrides.

“Silanna has achieved remarkable results on its previous MBE systems and Veeco is honored to celebrate this momentous accomplishment in our company history in partnership with Dr. Atanackovic and the Silanna team,” said Gerry Blumenstock, vice president and general manager, Veeco MBE Products. “As our customers explore novel materials and new applications, they can rely on Veeco to deliver innovative MBE systems, sources and components for use in complex R&D, as well as high-volume production environments.”

MBE is a highly precise thin-film deposition method for creating crystals by building up orderly layers of molecules on top of a substrate. MBE is used in industrial production processes as well as nanotechnology research in high-growth advanced computing, optics and photonics applications, to name a few. With over 600 systems shipped worldwide, Veeco provides the industry’s broadest portfolio of proven, reliable MBE systems, sources and components to serve a wide variety of markets and applications.

Data is only as good as humans’ ability to analyze and make use of it.

In materials research, the ability to analyze massive amounts of data–often generated at the nanoscale–in order to compare materials’ properties is key to discovery and to achieving industrial use. Jeffrey M. Rickman, a professor of materials science and physics at Lehigh University, likens this process to candy manufacturing:

“If you are looking to create a candy that has, say, the ideal level of sweetness, you have to be able to compare different potential ingredients and their impact on sweetness in order to make the ideal final candy,” says Rickman.

For several decades, nanomaterials–matter that is so small it is measured in nanometers (one nanometer = one-billionth of a meter) and can be manipulated at the atomic scale–have outperformed conventional materials in strength, conductivity and other key attributes. One obstacle to scaling up production is the fact that scientists lack the tools to fully make use of data–often in the terabytes, or trillions of bytes–to help them characterize the materials–a necessary step toward achieving “the ideal final candy.”

What if such data could be easily accessed and manipulated by scientists in order to find real-time answers to research questions?

The promise of materials like DNA-wrapped single-walled carbon nanotubes could be realized. Carbon nanotubes are a tube-shaped material which can measure as small as one-billionth of a meter, or about 10,000 times smaller than a human hair. This material could revolutionize drug delivery and medical sensing with its unique ability to penetrate living cells.

A new paper takes a step toward realizing the promise of such materials. Authored by Rickman, the article describes a new way to map material properties relationships that are highly multidimensional in nature. Rickman employs methods of data analytics in combination with a visualization strategy called parallel coordinates to better represent multidimensional materials data and to extract useful relationships among properties. The article, “Data analytics and parallel-coordinate materials property charts,” has been published in npj Computational Materials, a Nature Research journal.

“In the paper,” says Rickman, “we illustrate the utility of this approach by providing a quantitative way to compare metallic and ceramic properties–though the approach could be applied to any materials you want to compare.”

It is the first paper to come out of Lehigh’s Nano/Human Interface Presidential Engineering Research Initiative, a multidisciplinary research initiative that proposes to develop a human-machine interface to improve the ability of scientists to visualize and interpret the vast amounts of data that are generated by scientific research. It was kickstarted by a $3-million institutional investment announced last year.

The leader of the initiative is Martin P. Harmer, professor of materials science and engineering. In addition to Rickman, other senior faculty members include Anand Jagota, department chair of bioengineering; Daniel P. Lopresti, department chair of computer science and engineering and director of Lehigh’s Data X Initiative; and Catherine M. Arrington, associate professor of psychology.

“Several research universities are making major investments in big data,” says Rickman. “Our initiative brings in a relatively new aspect: the human element.”

According to Arrington, the Nano/Human Interface initiative emphasizes the human because the successful development of new tools for data visualization and manipulation must necessarily include a consideration of the cognitive strengths and limitations of the scientist.

“The behavioral and cognitive science aspects of the Nano/Human Interface initiative are twofold,” says Arrington. “First, a human-factors research model allows for analysis of the current work environment and clear recommendations to the team for the development of new tools for scientific inquiry. Second, a cognitive psychology approach is needed to conduct basic science research on the mental representations and operations that may be uniquely challenged in the investigation of nanomaterials.”

Rickman’s proposed method uses parallel coordinates, which is a method of visualizing data that makes it possible to spot outliers or patterns based on related metric factors. Parallel coordinates charts can help tease out those patterns.

The challenge, says Rickman, lies in interpreting what you see.

“If plotting points in two dimensions using X and Y axes, you might see clusters of points and that would tell you something or provide a clue that the materials might share some attributes,” he explains. “But, what if the clusters are in 100 dimensions?”

According to Rickman, there are tools that can help cut down on numbers of dimensions and eliminate non-relevant dimensions to help one better identify these patterns. In this work, he applies such tools to materials with success.

“The different dimensions or axes describe different aspects of the materials, such as compressibility and melting point,” he says.

The charts described in the paper simplify the description of high-dimensional geometry, enable dimensional reduction and the identification of significant property correlations and underline distinctions among different materials classes.

From the paper: “In this work, we illustrated the utility of combining the methods of data analytics with a parallel coordinates representation to construct and interpret multidimensional materials property charts. This construction, along with associated materials analytics, permits the identification of important property correlations, quantifies the role of property clustering, highlights the efficacy of dimensional reduction strategies, provides a framework for the visualization of materials class envelopes and facilitates materials selection by displaying multidimensional property constraints. Given these capabilities, this approach constitutes a powerful tool for exploring complex property interrelationships that can guide materials selection.”

Returning to the candy manufacturing metaphor, Rickman says: “We are looking for the best methods of putting the candies together to make what we want and this method may be one way of doing that.”

New frontier, new approaches

Creating a roadmap to finding the best methods is the aim of a 2½-day, international workshop called “Workshop on the Convergence of Materials Research and Multi-Sensory Data Science” that is being hosted by Lehigh University in partnership with The Ohio State University.

The workshop–which will take place at Bear Creek Mountain Resort in Macungie, PA from June 11-13, 2018–will bring together scientists from allied disciplines in the basic and social sciences and engineering to address many issues involved in multi-sensory data science as applied to problems in materials research.

“We hope that one outcome of the workshop will be the forging of ongoing partnerships to help develop a roadmap to establishing a common language and framework for continued dialogue to move this effort of promoting multi-sensory data science forward,” says Rickman, who is Principal Investigator on an National Science Foundation (NSF) grant, awarded by the Division of the Materials Research in support of the workshop.

Co-Principal Investigator, Nancy Carlisle, assistant professor in Lehigh’s Department of Psychology, says the conference will bring together complementary areas of expertise to allow for new perspectives and ways forward.

“When humans are processing data, it’s important to recognize limitations in the humans as well as the data,” says Carlisle. “Gathering information from cognitive science can help refine the ways that we present data to humans and help them form better representations of the information contained in the data. Cognitive scientists are trained to understand the limits of human mental processing- it’s what we do! Taking into account these limitations when devising new ways to present data is critical to success.”

Adds Rickman: “We are at a new frontier in materials research, which calls for new approaches and partners to chart the way forward.”

Working up a sweat from carrying a heavy load? That is when the textile works at its best. Researchers at Chalmers University of Technology have developed a fabric that converts kinetic energy into electric power, in cooperation with the Swedish School of Textiles in Borås and the research institute Swerea IVF. The greater the load applied to the textile and the wetter it becomes the more electricity it generates. The results are now published in the Nature Partner journal Flexible Electronics.

Chalmers researchers Anja Lund and Christian Müller have developed a woven fabric that generates electricity when it is stretched or exposed to pressure. The fabric can currently generate enough power to light an LED, send wireless signals or drive small electric units such as a pocket calculator or a digital watch.

The technology is based on the piezoelectric effect, which results in the generation of electricity from deformation of a piezoelectric material, such as when it is stretched. In the study the researchers created a textile by weaving a piezoelectric yarn together with an electrically conducting yarn, which is required to transport the generated electric current.

“The textile is flexible and soft and becomes even more efficient when moist or wet,” Lund says. “To demonstrate the results from our research we use a piece of the textile in the shoulder strap of a bag. The heavier the weight packed in the bag and the more of the bag that consists of our fabric, the more electric power we obtain. When our bag is loaded with 3 kilos of books, we produce a continuous output of 4 microwatts. That’s enough to intermittently light an LED. By making an entire bag from our textile, we could get enough energy to transmit wireless signals.”

The piezoelectric yarn is made up of twenty-four fibres, each as thin as a strand of hair. When the fibres are sufficiently moist they become enclosed in liquid and the yarn becomes more efficient, since this improves the electrical contact between the fibres. The technology is based on previous studies by the researchers in which they developed the piezoelectric fibres, to which they have now added a further dimension.

“The piezoelectric fibres consist of a piezoelectric shell around an electrically conducting core,” Lund says. “The piezoelectric yarn in combination with a commercial conducting yarn constitute an electric circuit connected in series.”

Previous work by the researchers on piezoelectric textiles has so far mainly focused on sensors and their ability to generate electric signals through pressure sensitivity. Using the energy to continuously drive electronic components is unique.

“Woven textiles from piezoelectric yarns makes the technology easily accessible and it could be useful in everyday life. It’s also possible to add more materials to the weave or to use it as a layer in a multi-layer product. It requires some modification, but it’s possible,” Lund says.

The researchers consider that the technology is, in principle, ready for larger scale production. It is now mainly up to industrial product developers to find out how to make use of the technology. Despite the advanced technology underlying the material, the cost is relatively low and is comparable with the price of Gore-Tex. Through their collaboration with the Swedish School of Textiles in Borås the researchers have been able to demonstrate that the yarn can be woven in industrial looms and is sufficiently wear-resistant to cope with the harsh conditions of mass production.