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Tag: Materials

  • High-Tech Materials Boost The Efficiency of Flexible Digital Screens

    High-Tech Materials Boost The Efficiency of Flexible Digital Screens

    High-end screens in our digital devices—such as TVs, smartphones, laptops, and gaming consoles—are driven by organic light-emitting diodes (OLEDs).
    A paper from the lab of Assoc. Prof. Sihong Wang at the University of Chicago Pritzker School of Molecular Engineering clears two major hurdles for creating the next generation of stretchable OLED screens. Image Credits: UChicago Pritzker School of Molecular Engineering / Jason Smith

    High-end screens in our digital devices—such as TVs, smartphones, laptops, and gaming consoles—are driven by organic light-emitting diodes (OLEDs).

    If these displays could conform to any 3D or irregular surface, they could enable technologies such as wearable electronics, medical implants, and humanoid robots that more seamlessly integrate with—or mimic—the soft human body.

    “While displays are the most obvious application, stretchable OLEDs could also serve as light sources for devices used in monitoring, detection, and diagnosis of major health issues like diabetes, cancer, and heart conditions,” said Wei Liu, a former postdoctoral researcher in the lab of University of Chicago Pritzker School of Molecular Engineering Associate Professor Sihong Wang.

    Pioneering Stretchable OLEDs

    Now a professor at Soochow University, Liu is the first author of a paper published today in Nature Materials that showcases the next generation of OLED screens.

    Wang’s UChicago PME team developed a high-efficiency electroluminescent material that stretches over twice its length while maintaining a fluorescent pattern. However, the screen still required two rigid layers—the cathode and the electron transport layer—for proper function.

    “Our ultimate aim is to create a high-performance, fully stretchable, light-emitting device,” said co-author Cheng Zhang, Ph.D. ’25, now a display engineer at Apple. “This study focuses on the cathode and electron transport layers, which had remained major, unsolved challenges for stretchable OLED screens.”

    In this latest work, the team overcame these final rigid barriers using an innovative aluminum gel and a new class of conductive polymers.

    UChicago Pritzker School of Molecular Engineering Assoc. Prof. Sihong Wang and his team aspire to advance stretchable OLEDs into a commercially viable technology with performance on par with today’s rigid OLEDs, enabling their use across a wide range of smart, human-integrated electronics and humanoid systems. Image Credits: UChicago Pritzker School of Molecular Engineering / Jason Smith

    New strategy makes reactive aluminum stretchable for cathodes

    Electrons enter an OLED device through the cathode, typically composed of aluminum. However, creating a stretchable form of aluminum is extremely difficult.

    After experimenting with multiple unsatisfactory substitutes and reviewing the scientific literature, the team made an unexpected discovery: to make aluminum stretchable, it actually had to be rendered brittle.

    Liquid-Metal Embrittlement

    Metals that are liquid at room temperature tend to be highly corrosive to most other metals. Engineers learn to avoid the well-known phenomenon called “liquid-metal embrittlement.”

    “If you put a droplet of this liquid metal on aluminum foil, the foil will quickly break apart,” Wang explained. “Normally, this is undesirable because it damages materials, and engineers actively avoid it.”

    However, the UChicago PME team aimed to harness, rather than prevent, this embrittlement—embedding a thin layer of aluminum within a stretchable substrate.

    “Even when the embrittlement occurs, and the aluminum fractures into small pieces, the material as a whole remains structurally intact,” Wang said.

    Liquid Metal Keeps Devices Intact

    The aluminum no longer breaks apart—it crackles. Tiny cracks appear when the material stretches and close when it returns to shape, like folded paper. Any larger gaps are filled by the surrounding liquid metal, maintaining the device’s overall functionality.

    The team created an alloy of gallium and indium and pre-mixed aluminum particles to improve bonding with the aluminum film.

    “Gallium-indium alloy is a liquid metal that flows like water,” explained UChicago PME Ph.D. student Zhiming Zhang. “Our aluminum-infused liquid metal behaves more like a gel.”

    After a month of aging tests, the aluminum liquid metal’s electrical properties remained stable.

    Polymer Family Transports Electrons to the Emissive Layer

    For an OLED to shine, electrons must flow smoothly from the cathode to the light-emitting layer, hopping across “energy steps.” If any step is too high, electrons get stuck and brightness drops.

    Electron transport layers (ETLs) reduce these barriers and enable efficient flow. To make a stretchable version of this normally brittle layer, the team designed a new family of polymers with conductive triazine rings connected by flexible alkyl chains. The rings carry electrons, while the chains provide stretchiness.

    “The balance is key,” Wang said. “More alkyl chains increase stretchability but lower conductivity; fewer chains boost conductivity but reduce flexibility.”

    By adjusting the ratio of chains to rings, the team created an optimized ETL. Paired with their stretchable aluminum cathode, these innovations advance the development of flexible OLEDs.

    Stretchable Screens for Wearables and Robotics

    Looking ahead, Wang’s team aims to make stretchable OLEDs commercially viable, matching the performance of rigid screens and enabling integration into wearable electronics and humanoid systems.

    Read the original article on: For an OLED to shine, electrons must flow smoothly from the cathode to the light-emitting layer, hopping across “energy steps.” If any step is too high, electrons get stuck and brightness drops.

    Electron transport layers (ETLs) reduce these barriers and enable efficient flow. To make a stretchable version of this normally brittle layer, the team designed a new family of polymers with conductive triazine rings connected by flexible alkyl chains. The rings carry electrons, while the chains provide stretchiness.

    “The balance is key,” Wang said. “More alkyl chains increase stretchability but lower conductivity; fewer chains boost conductivity but reduce flexibility.”

    By adjusting the ratio of chains to rings, the team created an optimized ETL. Paired with their stretchable aluminum cathode, these innovations advance the development of flexible OLEDs.

    Looking ahead, Wang’s team aims to make stretchable OLEDs commercially viable, matching the performance of rigid screens and enabling integration into wearable electronics and humanoid systems.

    Read the original article on: Tech Xplore

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  • Affordable Materials Turn Waste Carbon into High-Energy Compounds

    Affordable Materials Turn Waste Carbon into High-Energy Compounds

    Converting waste carbon into valuable products is essential for sustainable manufacturing. We can recycle carbon dioxide into carbon monoxide and then convert it into energy-dense compounds using electricity. However, current systems rely on anion exchange membranes that degrade over time when exposed to organic substances, reducing their overall efficiency.
    Feng Jiao’s lab created a diaphragm-based carbon monoxide electrolyzer design using a gas-diffusion electrode with copper nanoparticles as a cathode and nickel-iron oxide as an anode. The results show that diaphragms can be a scalable and durable solution for carbon monoxide conversion, making the process cheaper and more compatible with renewable energy sources. Image Credits: Jiao lab

    Converting waste carbon into valuable products is essential for sustainable manufacturing. We can recycle carbon dioxide into carbon monoxide and then convert it into energy-dense compounds using electricity. However, current systems rely on anion exchange membranes that degrade over time when exposed to organic substances, reducing their overall efficiency.

    Low-Cost Diaphragms Offer Efficient Alternative for Carbon Conversion

    A research team led by Feng Jiao, the Lauren and Lee Fixel Distinguished Professor at the McKelvey School of Engineering, Washington University in St. Louis, discovered that durable, low-cost materials known as porous diaphragms can serve as effective substitutes for traditional membranes in the carbon monoxide conversion process.

    Through testing multiple types of diaphragms, the team found that some matched or even outperformed commercial polymer-based membranes under various operating conditions.

    The study, published on September 26 in Nature Communications, lists postdoctoral researcher Wanyu Deng and doctoral student Siyang Xing as the paper’s first authors.

    Zirfon Diaphragms Enhance Electrolyzer Performance

    Diaphragms efficiently block the crossover of gas products between the cathode and anode while being made from inexpensive materials. Jiao’s team created a carbon monoxide electrolyzer using Zirfon diaphragms, which ran over 250 hours at 60°C—outlasting commercial membranes (~150 hours). A larger Zirfon-based electrolyzer also operated reliably for 700 hours.

    “These findings demonstrate that diaphragms offer a scalable and durable option for carbon monoxide conversion, reducing costs and improving compatibility with renewable energy systems,” said Jiao, who also serves as director of the Center for Carbon Management and associate director of the NSF CURB Engineering Research Center.

    The researchers plan to further enhance their electrolysis technologies to improve efficiency, recognizing that making the waste-gas conversion process more cost-effective and efficient will accelerate the transition toward circular and sustainable manufacturing systems.

    Read the original article on: Tech Xplore

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  • PHNX Materials Found a Way to Cut Concrete’s Carbon Footprint Using Coal Waste

    PHNX Materials Found a Way to Cut Concrete’s Carbon Footprint Using Coal Waste

    Coal-fired power plants have caused considerable harm over the last hundred years, contributing to everything from climate change and acid rain to black lung disease and heart conditions. Overall, their impact has been overwhelmingly negative.
    Credit: Pixabay

    Coal-fired power plants have caused considerable harm over the last hundred years, contributing to everything from climate change and acid rain to black lung disease and heart conditions. Overall, their impact has been overwhelmingly negative.

    However, hidden within the ashes they produce lies a surprising environmental benefit.

    Up to 30% Cement Replacement: How Fly Ash Helps Curb Carbon Emissions

    “Fly ash can substitute for up to 30% of cement,” explained Krish Mehta, co-founder and CEO of PHNX Materials, in an interview with TechCrunch. Since cement production is highly carbon-intensive, using fly ash in its place can substantially lower concrete’s carbon emissions.

    PHNX Materials has developed a method to remove sulfur and carbon—unwanted impurities for concrete manufacturers—from fly ash. This not only makes the ash more suitable for use in concrete but also yields recoverable sulfur and aluminum, both valuable byproducts found in the ash.

    PHNX Materials Secures $2.5M Seed Round Backed by Top Climate Investors

    TechCrunch has learned exclusively that the startup recently secured a $2.5 million seed investment. The funding round was led by Divergent Capital, KdT Ventures, and Overture, with additional backing from Jane Woodward.

    Ash has played a role in concrete production for thousands of years. The Ancient Romans utilized volcanic ash, and more recently, fly ash from coal-fired power plants has been adopted by state transportation agencies. For instance, Caltrans mandates that concrete used in its projects contain at least 25% fly ash.

    According to Jorge Osio-Norgaard, co-founder and CTO of PHNX Materials, fly ash contributes to the stability of concrete mixtures. Without it, a specific chemical reaction may cause the aggregate—the small stones within the concrete—to transform into a gel that expands and ultimately cracks the structure.

    Fly Ash Enhances Infrastructure Longevity, Says PHNX Co-Founder

    “When you’re investing a billion dollars into infrastructure like highways or bridges, you expect it to endure for a century,” said Osio-Norgaard. “Fly ash plays a key role in making that possible.”

    The shutdown of coal-fired power plants has significantly reduced the supply of ash available to the concrete industry. While coal once accounted for 51% of electricity production in the U.S., it now contributes only 15%.

    This decline has given rise to a new sector focused on recovering coal ash. Companies are now excavating ash pits to extract usable fly ash, lightly processing it, and selling it to concrete producers. However, not all of the recovered ash meets quality standards, according to Mehta, which has led to a supply shortage and rising prices.

    As a consequence, concrete manufacturers have been reducing the amount of fly ash in their mixes to around 8%, Mehta said. Though they could incorporate as much as 30%, they’re compensating for the shortfall with extra cement — a substitute that costs nearly twice as much per ton as fly ash.

    That trade-off not only compromises the longevity of concrete but also contributes significantly to its carbon emissions. Cement production emits CO2 both from the chemical reaction involved in its creation and from the burning of fossil fuels needed to generate the high temperatures required. According to the EPA, manufacturing one ton of cement in the U.S. results in about 0.8 tons of carbon dioxide emissions.

    “We saw the potential to decarbonize the industry quickly and at scale by tapping into a new source of ash,” Mehta explained.

    PHNX Unlocks Value from Landfill Fly Ash, Recovering Key Materials for Multiple Industries

    PHNX’s method involves recovering fly ash from landfills and extracting materials like sulfur and aluminum. The company is also exploring the recovery of rare earth elements. The processed ash will be sold to concrete producers, while the extracted compounds—such as sulfur, which has applications in fertilizer—will be marketed to other industries.

    By turning the contaminants found in the roughly 843 fly ash landfills across the U.S. into valuable resources, PHNX believes it can provide the concrete industry with a more sustainable, lower-emission alternative. “We saw the potential to decarbonize the industry quickly and at scale by tapping into a new source of ash,” Mehta reiterated.

    Read the original article on: TechCrunch

    Read more: How to Greatly Reduce Industrial Mercury Emissions

  • A Unique Method for Manipulating Atomic Layers to Create Cutting-Edge Materials

    A Unique Method for Manipulating Atomic Layers to Create Cutting-Edge Materials

    Physics and materials science comprehensively understand the interaction of light with naturally occurring materials. However, over the last few decades, scientists have engineered metamaterials capable of interacting with light in unconventional ways, surpassing the inherent physical limitations of naturally occurring materials.
    Interfacial nonlinear susceptibility in twisted bilayer WS2. Credit: Nature Photonics (2023). DOI: 10.1038/s41566-023-01318-6

    Physics and materials science comprehensively understand the interaction of light with naturally occurring materials. However, over the last few decades, scientists have engineered metamaterials capable of interacting with light in unconventional ways, surpassing the inherent physical limitations of naturally occurring materials.

    A metamaterial typically consists of arrays of “meta-atoms,” structured at a scale of around a hundred nanometers. While the precise arrangements of these meta-atoms allow for specific light-matter interactions, the large size of meta-atoms compared to regular atoms, which are smaller than a nanometer, has restricted the practical applications of metamaterials.

    Bo Zhen’s Team Unveils Groundbreaking Method for Engineering Atomic Structures

    In a breakthrough, a collaborative research team led by Bo Zhen at the University of Pennsylvania has introduced a new method. This approach involves engineering the atomic structures of materials by stacking two-dimensional arrays in spiral formations, enabling novel light-matter interactions. This innovative technique overcomes existing technical limitations and opens avenues for advanced lasers, imaging, and quantum technologies. The study’s findings were published in the journal Nature Photonics.

    Zhen, a senior author and assistant professor in the School of Arts & Sciences at Penn, explains the analogy: “It’s similar to stacking a deck of cards but twisting each card slightly before adding it to the pile. This twist changes how the entire ‘deck’ responds to light, enabling it to exhibit new properties that individual layers, or traditional stacks, do not possess.”

    Bumho Kim, the paper’s first author and a postdoctoral researcher in the Zhen Lab, elucidates that by stacking layers of tungsten disulfide (WS2) and twisting them at specific angles, they introduced screw symmetries.

    Kim emphasizes the crucial aspect of this technique, stating, “The key is in manipulating the twist. By twisting the layers at precise angles, you alter the symmetry of the stack. Symmetry, in this context, pertains to the limitations imposed on certain material properties—such as their interaction with light—based on their spatial arrangement.“


    Through precise control of the atomic-scale arrangement, the researchers have altered the capabilities of these materials. By manipulating the twist across multiple layers of WS2, they have created 3D nonlinear optical materials.

    WS2 Single Layer’s Symmetry and Second-Harmonic Generation Explained by Kim

    Kim clarifies that a single layer of WS2 exhibits specific symmetries that enable particular interactions with light, such as second-harmonic generation (SHG), where two photons at a given frequency can interact with the material to produce a new photon at double the frequency.

    However, when two layers of WS2 are stacked with a twist angle different from the conventional 0° or 180°, the mirror symmetries present in the single layer are disrupted. This broken mirror symmetry is crucial, leading to a chiral response—an entirely novel aspect not observed in individual layers.

    The chiral response is significant because it results from the coupling between the electronic wavefunctions of the two layers, a phenomenon unique to twisted interfaces. Zhen notes an intriguing property: the sign of the chiral nonlinear response flips when the twist angle is reversed, showcasing direct control over nonlinear properties by adjusting the twist angle between layers, a level of tunability with revolutionary potential for designing optical materials with custom responses.

    Unraveling SHG Responses in Multi-Layered Stacks with Twist Angles

    Progressing from bilayers to trilayers and beyond, the researchers observed how interfacial SHG responses can constructively or destructively interfere based on the twist angles between layers. In stacks with layers in multiples of four, the chiral responses from all interfaces add up, while the in-plane responses cancel out, resulting in a material that exhibits only chiral nonlinear susceptibilities—an achievement requiring precise stacking and twisting of the layers.

    The researchers discovered that screw symmetry introduces new selectivity for the light’s electric field in the material, influencing its direction and intensity. Kim highlights how they identified that screw symmetry enables a new type of light generation in twisted four- and eight-layer stacks: counter-circularly polarized third harmonic generation, where light travels in the opposite spiral direction—a quality absent in constituent WS2 monolayers.

    In experimental tests, the researchers validated the predicted nonlinearities in various configurations of twisted WS2 stacks. They observed new nonlinear responses and circular selectivity in twisted WS2 stacks, presenting possibilities not found in naturally occurring WS2 and potentially revolutionizing the field of nonlinear optics.

    Read the original article on: Phys Org

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