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Category: engineering

Encapsulated PbS quantum dots boost solar water splitting without sacrificial agents

A research team affiliated with UNIST has developed stable and efficient chalcogenide-based photoelectrodes, addressing a longstanding challenge of corrosion. This advancement paves the way for the commercial viability of solar-driven water splitting technology—producing hydrogen directly from sunlight without electrical input.

Jointly led by Professors Ji-Wook Jang and Sung-Yeon Jang from the School of Energy and Chemical Engineering, the team reported a highly durable, corrosion-resistant metal-encapsulated PbS quantum dot (PbS-QD) solar cell-based photoelectrode that delivers both high photocurrent and long-term operational stability for photoelectrochemical (PEC) water splitting without the need for sacrificial agents. The research is published in the journal Nature Communications.

PEC water splitting is a promising route for sustainable hydrogen production, where sunlight is used to drive the decomposition of water into hydrogen and oxygen within an electrolyte solution. The efficiency of this process depends heavily on the stability of the semiconductor material in the photoelectrode, which absorbs sunlight and facilitates the electrochemical reactions. Although chalcogenide-based sulfides, like PbS are highly valued for their excellent light absorption and charge transport properties, they are prone to oxidation and degradation when submerged in water, limiting their operational stability.

Quantum defects in carbon nanotubes as single-photon sources

This Review surveys progress in the development of carbon nanotubes as single-photon sources for emerging quantum technologies, with a focus on chemical synthesis and quantum defect engineering, computational studies of structure-property relationships, and experimental investigations of quantum optical properties.

Stabilized iron catalyst could replace platinum in hydrogen fuel cells

Japan and California have embraced hydrogen fuel-cell technologies, a form of renewable energy that can be used in vehicles and for supplying clean energy to manufacturing sectors. But the technology remains expensive due to its reliance on precious metals such as platinum. Engineers at Washington University in St. Louis are working on this challenge, finding ways to stabilize ubiquitous iron components for use in fuel cells to replace the expensive platinum metals, which would make hydrogen fuel-cell vehicles more affordable.

Cost challenges for fuel-cell vehicles

“The hydrogen fuel cell has been successfully commercialized in Japan and California in the U.S.,” said Gang Wu, a professor of energy, environmental and chemical engineering at the McKelvey School of Engineering. “But these vehicles struggle to compete with the battery vehicle and combustion engine vehicle, with cost being the main issue.”

Study reveals microscopic origins of surface noise limiting diamond quantum sensors

A new theoretical study led by researchers at the University of Chicago and Argonne National Laboratory has identified the microscopic mechanisms by which diamond surfaces affect the quantum coherence of nitrogen-vacancy (NV) centers—defects in diamond that underpin some of today’s most sensitive quantum sensors. The study has appeared in Physical Review Materials and was selected to be an Editors’ Suggestion paper.

“One long-standing challenge has been understanding why shallow NV centers lose coherence so quickly,” said Giulia Galli, professor at the University of Chicago Pritzker School of Molecular Engineering (UChicago PME) and senior scientist at Argonne National Laboratory. “By combining first-principles surface models with quantum dynamics simulations, we understood that the culprit of decoherence is not just which spins live on the diamond surface, but how they move: surface noise is dynamical.”

The findings of the study provide clear, physics-based guidelines for engineering diamond surfaces that help preserve quantum coherence, a key requirement for quantum sensing and emerging quantum information technologies.

Tuning topological superconductors into existence by adjusting the ratio of two elements

Today’s most powerful computers hit a wall when tackling certain problems, from designing new drugs to cracking encryption codes. Error-free quantum computers promise to overcome those challenges, but building them requires materials with exotic properties of topological superconductors that are incredibly difficult to produce. Now, researchers at the University of Chicago Pritzker School of Molecular Engineering (UChicago PME) and West Virginia University have found a way to tune these materials into existence by simply tweaking a chemical recipe, resulting in a change in many-electron interactions.

The team adjusted the ratio of two elements— tellurium and selenium —that are grown in ultra-thin films. By doing so, they found they could switch the material between different quantum phases, including a highly desirable state called a topological superconductor.

The findings, published in Nature Communications, reveal that as the ratio of tellurium and selenium changes, so too do the correlations between different electrons in the material—how strongly each electron is influenced by those around it. This can serve as a sensitive control knob for engineering exotic quantum phases.

Dream engineering can help solve ‘puzzling’ questions: Study offers insights to optimizing sleep

We’ve all heard the best approach to solve a problem is to “sleep on it.” It turns out there may be more truth to this adage than previously thought. While stories abound of eureka moments surfacing from dreams, scientific evidence has remained elusive, due to the challenge of systematically manipulating dreams.

A new study by neuroscientists at Northwestern University validates the possibility of influencing dreams and offers a crucial step to support the theory that dreams in REM sleep—the rapid eye movement phase of sleep in which lucid dreaming can occur—may be especially conducive to helping individuals come up with creative solutions to a problem.

The study has been published in the journal Neuroscience of Consciousness.

Peppermint oil plasma coating could cut catheter infections without releasing drugs

Australian researchers have developed a high‑performance coating made from peppermint essential oil that can be applied to the surfaces of many commonly used medical devices, offering a safer way to protect patients from infection and inflammation.

Matthew Flinders Professor and senior author of the new study, Professor Krasimir Vasilev, says the idea emerged after noticing that eating peppermint leaves from his drink significantly relieved his sore throat, inspiring him to explore whether its bioactivity could be converted into a durable coating using plasma technology—something he has been researching for more than two decades.

The team from Flinders’s Biomedical Nanoengineering Laboratory—including Professor Vasilev (Director), Associate Professor Vi‑Khanh Truong, Dr. Andrew Hayes, and Ph.D. candidates Trong Quan Luu and Tuyet Pham—created a nanoscale peppermint‑oil coating that protects against infection, inflammation and oxidative stress, while remaining compatible with human tissue and suitable for medical materials.

New design tool 3D-prints woven metamaterials that stretch and fail predictably

Metamaterials—materials whose properties are primarily dictated by their internal microstructure, and not their chemical makeup—have been redefining the engineering materials space for the last decade. To date, however, most metamaterials have been lightweight options designed for stiffness and strength.

New research from the MIT Department of Mechanical Engineering introduces a computational design framework to support the creation of a new class of soft, compliant, and deformable metamaterials. These metamaterials, termed 3D woven metamaterials, consist of building blocks that are composed of intertwined fibers that self-contact and entangle to endow the material with unique properties.

Physicists achieve near-zero friction on macroscopic scales

For the first time, physicists in China have virtually eliminated the friction felt between two surfaces at scales visible to the naked eye. In demonstrating “structural superlubricity,” the team, led by Quanshui Zheng at Tsinghua University, have resolved a long-standing debate surrounding the possibility of the effect. Published in Physical Review Letters, the result could potentially lead to promising new advances in engineering.

When two objects slide over each other, any roughness on their surfaces will almost inevitably resist the motion, creating the force of friction. Yet in 2004, physicists showed that friction can be virtually eliminated between two graphite surfaces, simply by rotating their respective molecular structures.

Named structural superlubricity (SSL), the effect is highly desired by engineers; in principle, allowing them to eliminate wear on both surfaces and minimize energy lost as waste heat.

Ultra-thin metasurface can generate and direct quantum entanglement

Quantum technologies, devices and systems that process, store, detect, or transfer information leveraging quantum mechanical effects, have the potential to outperform classical technologies in a variety of tasks. An ongoing quest within quantum engineering is the realization of a so-called quantum internet: a network conceptually analogous to today’s internet, in which distant nodes are linked through shared quantum resources, most notably quantum entanglement.

Researchers at Nanjing University and University of Science and Technology of China have developed a new ultra-thin metasurface that could contribute to this goal, as it can control the behavior of light, while also generating and directing entanglement across many channels.

This metasurface, presented in a paper published in Physical Review Letters, has so far proved to be promising for the development of scalable and integrated quantum technologies.

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