Recent uci_eng_mse_oapdeposits items

Characterization of dynamics of encapsulated small molecule Nile red in biodegradable polymer using 2D IR methods

Tue, 28 Apr 2026 00:00:00 +0000

Biodegradable polymers are seen as a promising option for drug delivery. Here, we applied 2D IR methods with scattering removal to characterize the vibrational dynamics of encapsulated Nile red in amphiphilic block copolymer polyethylene glycol-block-polycaprolatone. Nile red was chosen because it is a commonly used hydrophobic dye molecule. Comparing the absorptive spectra, the splitting of diagonal peaks in nonrephasing spectra confirms the encapsulation of Nile red in the presence of polymer droplets. Pump-probe lifetime data exhibit multiple exponential decays and oscillations, which were fitted to quantify the encapsulation. Waiting time dependent 2D IR spectra were acquired and simulated to characterize the dynamics of the encapsulated Nile red. From these results, we can determine that a portion of the Nile red population, in the presence of polymer, exhibits distinctly different vibrational dynamics, consistent with encapsulation within coacervate microdroplets.

Halide Ligands Control Optical and Chiroptical Response of DNA-Stabilized Ag28 Clusters in the Near-Infrared Region: Theoretical Prediction and Experimental Confirmation

Thu, 26 Mar 2026 00:00:00 +0000

Recent experiments [ Romolini ; Small Structures 2025, 2500022 ] uncovered the crystallographic structure of a near-infrared (NIR) emitting DNA-stabilized silver nanocluster, DNA2Ag28Cl2, which has two chloridos bound to the silver core. Here, we study the role of the halido in the cluster’s photophysical properties by replacing X = Cl with X = Br, I, H2O, or OH in a computational model for density functional theory (DFT) calculations. The calculations predict a systematic red shift of the NIR absorption and enhancement of a negative circular dichroism (CD) signal in the range of 810–860 nm when Cl, Br, and I are used as halide ligands, respectively. Leaving the two halido sites empty but coordinated by water molecules blue-shifts the linear absorption and CD signal from 810 nm and dramatically switches the CD sign. The explanations for this behavior are found by a detailed analysis of the electronic structure and the impact of the X ligands to the frontier orbitals. We directly...

A nanoporous capacitive electrochemical ratchet for continuous ion separations

Wed, 25 Mar 2026 00:00:00 +0000

Directed ion transport in liquid electrolyte solutions underlies many phenomena in natural and industrial settings. While nature has evolved structures that drive continuous ion flow without Faradaic redox reactions, establishing this process in synthetic systems has been challenging. Here we report an ion pump that drives aqueous ions against a force using a capacitive ratchet mechanism independent of redox reactions. Modulation of an electric potential between thin metallic layers on either face of a nanoporous alumina wafer immersed in solution results in persistent voltages and ionic currents. This occurs due to the nonlinear capacitive nature of electric double layers, whose repeated charging and discharging sustains a continuous ion flux. Using this approach, we demonstrate ratchet-driven electrodialysis that reaches a 50% decrease in the conductivity of the solution in a dilution cell. These ratchet-based ion pumps can enable continuous desalination and selective ion separation...

Gerischer Electrochemistry Today

Fri, 13 Mar 2026 00:00:00 +0000

Semiconductor photoelectrochemistry is a dynamic and interdisciplinary field at the forefront of research in solar fuels, energy conversion, and catalysis. This Perspective captures the collective insights from the second Gerischer Electrochemistry Today Symposium, held at Colorado State University in Fort Collins, CO, in August 2024, which convened leading researchers, early-career scientists, and industry partners to define the critical next steps for the field. Through interactive sessions, technical talks, panel discussions, and training initiativesincluding a Semiconductor Electrochemistry Bootcampthe symposium emphasized three pillars of advancement: (i) facilitating the exchange of new ideas in semiconductor electrochemistry and charge separation; (ii) fostering the development of future researchers, research topics, and participation in the semiconductor workforce; and (iii) building community. This Energy Focus distills key themes from the meeting and identifies major...

Effect of cell compression on the performance and the structure of proton exchange membrane water electrolyzer (PEMWE) assembly

Thu, 12 Mar 2026 00:00:00 +0000

In the field of water electrolysis, the proton exchange membrane water electrolyzer (PEMWE) is currently the most advanced technology for producing hydrogen without emitting CO2. Although PEMWE plants are already in operation, further research is needed to improve cell efficiency and reduce the use of rare materials, such as iridium oxide catalysts for the oxygen evolution reaction (OER). One of the main causes of performance loss in PEMWE is the relatively low electric conductivity of the porous transport layer (PTL) and of the anode catalyst layer, which results in ohmic losses and low catalyst utilization during high current density operation. The objective of this study is to investigate how optimization of the PTL and electrode interface can increase the cell performance. To this end, we tested different cell assemblies using fibrous and sintered PTLs, decreasing membrane thickness, reducing iridium loading, and inserting a microporous layer to increase contact surface area....

Xeno-nucleic acids support formation of Ag(I)-mediated duplexes and silver nanoclusters

Thu, 12 Mar 2026 00:00:00 +0000

The expanded backbone chemistries of xeno-nucleic acids (XNAs) hold significant promise for emerging areas of synthetic biology and nanomaterials, but metal-mediated XNA interactions remain largely unexplored. Here, we use a combination of circular dichroism spectroscopy and mass spectrometry to show that XNAs can form Ag+-mediated duplex structures resembling their DNA counterparts. XNAs with a range of different backbone compositions are found to stabilize photoluminescent silver nanoclusters with spectral properties that can be tuned based on their respective backbone chemistry. The resistance of silver nanoclusters to nuclease digestion is also compared for DNA and XNAs. These results show that XNA backbone chemistry provides a new tool beyond nucleobase sequence for controlling and expanding the properties of nucleic acid-stabilized silver nanoclusters and metal-mediated DNA duplexes.

Using X-ray radiography to study oxygen flow in a proton exchange membrane electrolyzer operating under balanced pressure conditions

Wed, 11 Mar 2026 00:00:00 +0000

Of the various water electrolyzer technologies, the proton exchange membrane electrolyzer (PEMWE) is one of the best solutions for producing clean hydrogen without releasing CO2. In order to allow for widespread use of clean hydrogen, it is necessary to decrease its cost, which is intrinsically related to system operation. Current PEMWE plants operate in differential mode, directly pressurizing hydrogen and benefiting from thermodynamic compression, which increases overall system efficiency. However, high differential pressure above 30 bar can cause membrane stress, resulting in membrane creeping and failure. Pressurizing the water and operating at balanced pressure allows hydrogen to be produced at higher pressures while preserving the integrity of the membrane and porous layers. Nevertheless, the impact of pressurizing water on PEMWE performance must be better understood to maximize performance under balanced pressure conditions. This study examined the impact of water...

Synergizing Chemical and AI Communities for Advancing Laboratories of the Future

Thu, 12 Feb 2026 00:00:00 +0000

The development of automated experimental facilities and the digitization of experimental data have introduced numerous opportunities to radically advance chemical laboratories. As many laboratory tasks involve predicting and understanding previously unknown chemical relationships, machine learning (ML) approaches trained on experimental data can substantially accelerate the conventional design-build-test-learn process. This outlook article aims to help chemists understand and begin to adopt ML predictive models for a variety of laboratory tasks, including experimental design, synthesis optimization, and materials characterization. Furthermore, this article introduces how artificial intelligence (AI) agents based on large language models can help researchers acquire background knowledge in chemical or data science and accelerate various aspects of the discovery process. We present three case studies in distinct areas to illustrate how ML models and AI agents can be leveraged to...

Unlocking Two‐Photon Chiral Signatures in DNA‐Stabilized Silver Nanoclusters: Two‐Photon Circular Dichroism and Circularly Polarized Luminescence

Thu, 12 Feb 2026 00:00:00 +0000

ABSTRACT Near‐infrared (NIR) emitters with chiroptical properties are a novel class of materials with significant promise for chiral sensing and optoelectronic applications. Chiral nanoparticles, in particular, offer distinct advantages over molecular chiral agents. However, their practical applications remain significantly hindered due to challenges to precisely control nanoparticle chirality and reduce heterogeneity. Here, we investigate one‐photon (1P) and two‐photon (2P) chiroptical properties of DNA‐stabilized silver nanoclusters (DNA‐Ag N ) as atomically defined, water‐soluble chiral nanoprobes. We perform a detailed analysis of 1P and 2P circular dichroism (1P‐CD and 2P‐CD, respectively) and circularly polarized luminescence (CPL) of (DNA) 2 [Ag 16 Cl 2 ] 8+ , a NIR emissive DNA‐Ag N with solved crystal structure, over a broad wavelength range. We observe that (DNA) 2 [Ag 16 Cl 2 ] 8+ exhibits 2P‐CD two orders of magnitude higher than 1P anisotropy factor, with additional...

Foundation Models for Zero-Shot Segmentation of Scientific Images without AI-Ready Data

Fri, 2 Jan 2026 00:00:00 +0000

Zero-shot and prompt-based models have excelled at visual reasoning tasks by leveraging large-scale natural image corpora, but they often fail on sparse and domain-specific scientific image data. We introduce Zenesis, a no-code interactive computer vision platform designed to reduce data readiness bottlenecks in scientific imaging workflows. Zenesis integrates lightweight multimodal adaptation for zero-shot inference on raw scientific data, human-in-the-loop refinement, and heuristic-based temporal enhancement. We validate our approach on Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) datasets of catalyst-loaded membranes. Zenesis outperforms baselines, achieving an average accuracy of 0.947, Intersection over Union (IoU) of 0.858, and Dice score of 0.923 on amorphous catalyst samples; and 0.987 accuracy, 0.857 IoU, and 0.923 Dice on crystalline samples. These results represent a significant performance gain over conventional methods such as Otsu thresholding and standalone...

Physical model and experimental validation of a high temperature proton exchange membrane electrochemical hydrogen pump cell for efficient single-stage extraction of low concentration hydrogen gas

Tue, 16 Dec 2025 00:00:00 +0000

There is interest in valorization of existing natural gas infrastructure to facilitate the co-transportation of hydrogen via blending of hydrogen gas initially at limited concentrations of 1–20 vol% H2 and to subsequently extract hydrogen at fuel cell quality standards (SAE J2719/ISO14687-2). High temperature proton exchange membrane electrochemical hydrogen pump (HT-PEM EHP) based on phosphoric acid doped polybenzimidazole (PA-PBI) exhibits good performance at elevated temperatures (>120 °C), which provides desirable tolerance to non-methane natural gas constituents that are problematic for lower temperature based EHP. To better understand the suitability of the HT-PEM EHP for such gas separation processes, a two-dimensional model of EHP based on PA-PBI was developed. The model is validated for several relevant operating conditions and across cells with differing amounts of phosphoric acid content in the electrodes. Operando micro x-ray computed tomography (CT) imaging...

Surface Charge in Electrical Double Layer as a Kinetic Descriptor of Electrocatalytic Reactions

Mon, 15 Dec 2025 00:00:00 +0000

The successful commercialization of electrochemical energy-conversion systems hinges on a deeper understanding of electrocatalytic reaction kinetics. Despite extensive research, a key descriptor that characterizes electrolyte effects on reaction kinetics remains elusive. Here, surface charge in electrical double layers (EDLs) is introduced as a descriptor for electrolyte-dependent kinetics. The surface charge is calculated with a continuum EDL model parameterized by density-functional theory. The model is validated by reproducing the anomalously low slope of Pt(111) in Parsons-Zobel plots. Strong correlations are observed between calculated surface charge and experimental kinetic currents for hydrogen evolution, oxygen reduction, and CO2-reduction reactions across various pH levels and cationic species. These correlations can be either promotional or inhibitory, depending on solute-intermediate interactions. In acidic media, incorporating adsorbate charge captures specific adsorption...

Lithium diffusion-controlled Li-Al alloy negative electrode for all-solid-state battery

Thu, 20 Nov 2025 00:00:00 +0000

Metal alloy negative electrodes are promising candidates for lithium all-solid-state batteries due to their high specific capacity and low cost. However, chemo-mechanical degradation and atomic transport limitations in the solid state remain unresolved challenges. Herein, we demonstrate a lithium-aluminum alloy negative electrode design (LixAl1, x = molar ratio of lithium to aluminum) based on a comprehensive understanding of the underlying diffusion mechanisms within the lithium-poor α (0 ≤ x ≤ 0.05) and lithium-rich β phases (0.95 ≤ x ≤ 1). The lithium-aluminum alloy negative electrodes with a higher lithium to aluminum ratio facilitate lithium migration through the β-LiAl phases, which serve as highly lithium-conductive channels with a lithium diffusion coefficient that is ten orders of magnitude higher than that of the α phase. In addition, a bulk dense negative electrode and an intimate negative electrode-electrolyte interface is demonstrated in the cross-sections...

Complementary biomolecular coassemblies direct energy transport for cardiac photostimulators

Wed, 8 Oct 2025 00:00:00 +0000

Charge and energy transport within living systems are fundamental processes that enable the autonomous function of excitable cells and tissues. To date, localized control of these transport processes has been enabled by genetic modification approaches to render light sensitivity to cells. Here, we present peptidic nanoassemblies as constituents of a cardiac biomaterial platform that leverages complementary sequence interactions to direct photoinduced energy transport at the cellular interface. Photophysical characterizations and conductivity measurements confirm the occurrence of energy/charge transfer and photocurrent generation upon optical excitation in both dry and electrolytic environments. Comparing an electrostatic sequence pair against a sequence-matched donor-acceptor coassembly, we demonstrate that the sequence design with charge complementarity shows more prominent photocurrent behavior. With the flanking bioadhesive units, the primary and stem cell-derived cardiomyocytes...

Enhancing water and oxygen transport through electrode engineering for AEM water electrolyzers

Tue, 9 Sep 2025 00:00:00 +0000

Anion-exchange membrane water electrolyzers (AEMWEs) can accelerate the deployment of more efficient and affordable hydrogen production solutions. Here, electrode structure is shown to affect water back-diffusion and oxygen transport, which, in return, governs overpotential behaviors in AEMWEs. Measurements indicate that electrode with copious catalytic sites produces water close to the AEM, creating a higher water gradient and driving water back-diffusion, which improves membrane hydration and mass transport. In situ measurement reveals a high pH gradient near the anode surface, which affects anode kinetics. Operando measurement shows reduced oxygen accumulation when decoupling oxygen production and transport on anode. Catalyst ink rheology and stability are tuned with additives to realize scalable fabrication of electrodes with enhanced transport features, allowing AEMWE to operate at 2 A cm−2 for over 1,000+ h at a 2.3 μV h−1 degradation rate. Analysis during and post-durability...

Spin Frustration and Unconventional Surface Spin Canting State in Van der Waals Ferromagnet/Antiferromagnet Heterostructures

Mon, 8 Sep 2025 00:00:00 +0000

Atomically flat surfaces of van der Waals (vdW) materials pave an avenue for addressing a long-standing fundamental issue of how a compensated antiferromagnet (AFM) surface frustrates a ferromagnetic (FM) overlayer in FM/AFM heterostructures. We investigate Fe₅GeTe₂/NiPS₃ vdW heterostructures by characterizing AFM and FM spins separately. We find that in-plane zig-zag AFM NiPS₃ develops three equivalent AFM domains, which are robust against external magnetic field and magnetic coupling with Fe₅GeTe₂. Moreover, evidence is provided of in-plane-AFM-induced perpendicular magnetic anisotropy (PMA) in adjacent Fe₅GeTe₂, and an unconventional out-of-plane surface spin canting state with the Fe₅GeTe₂ spins spatially turn from out-of-plane direction near the interface to in-plane direction away from the interface in Fe₅GeTe₂/NiPS₃. The out-of-plane...

Long-lived photoinduced polar states in metal halide perovskites

Mon, 8 Sep 2025 00:00:00 +0000

Ferroic polarization in hybrid perovskites is crucial for enhancing photovoltaic performance and developing potential electronic applications. Controlling ferroic polarization with an optical field enables probing of ferroic polarization without the unwanted interface ionic effects caused by electronic contacts. This study employs ultrafast near-infrared photoexcitation to control dynamic structural transitions in soft single crystalline hybrid Cu (II) halide perovskites, achieving a long-lived polar state (beyond 104 s) at room temperature. We probe reversible long-lived polar domains under near-infrared photoexcitation using in-situ second harmonic generation microscopy. Theoretical calculation informs the polar lattice microstrain likely induced by anisotropic structure deformation in octahedral copper halide under near-infrared photoexcitation. The reversible slow structure deformation is further confirmed by in-situ photo-induced X-ray diffraction measurement. This work provides...

Anion-Exchange-Membrane Electrolysis with Alkali-Free Water Feed

Mon, 8 Sep 2025 00:00:00 +0000

Hydrogen is a green and sustainable energy vector that can facilitate the large-scale integration of intermittent renewable energy, renewable fuels for heavy transport, and deep decarbonization of hard-to-abate industries. Anion-exchange-membrane water electrolyzers (AEM-WEs) have several achieved or expected competitive advantages over other electrolysis technologies, including the use of precious metal-free electrocatalysts at both electrodes, fluorine-free hydrocarbon-based ionomeric membranes and bipolar plates based on inexpensive materials. Contrasting the analogous proton-exchange-membrane system (PEM-WE), where pure water is circulated (no support electrolyte), the current generation of AEM-WEs necessitates the circulation of a dilute aqueous alkaline electrolyte for reaching high energy efficiency and durability. For several reasons, including but not limited to lower cost of balance-of-plant, lower operating cost and improved device's lifetime, achieving high cell efficiency...

Radular teeth matrix protein 1 directs iron oxide deposition in chiton teeth

Wed, 27 Aug 2025 00:00:00 +0000

Nature builds multiscale mineral structures with impressive mechanical properties through spatially and temporally orchestrated organic-mineral assembly. One example of regulated mineralization is found in hypermineralized and ultrahard magnetic teeth of chiton, which grind on rock to feed on algae. At early stages of tooth formation, iron oxide deposition is controlled using a chiton-specific radular teeth matrix protein 1 (RTMP1), which is transported into teeth through microvilli. RTMP1 spatially and temporally guides and enhances mineralization on chitinous fibers within the tooth, providing a hard, tough, and strong architecture that enables the organism to perform repetitive abrasive events to survive.

PyRESP: A flexible program for polarizable force field parameterizations

Wed, 13 Aug 2025 00:00:00 +0000

PyRESP: A flexible program for polarizable force field parameterizations

The effect of grain boundary yield and disconnections on grain boundary fracture strength

Wed, 13 Aug 2025 00:00:00 +0000

During high-temperature interfacial strain, e.g., creep or sintering, grain boundaries will sample non-equilibrium states associated with the non-equilibrium disconnections that mediate strain. This work tests the hypothesis that those non-equilibrium states should affect the mechanical properties of the grain boundary. High-temperature bicrystal tensile strain experiments performed on Sc-doped ZrO2 as a function of strain rate enable the observation of fracture before and after grain boundary yield. Yielded boundaries exhibit a median fracture strength ≈ 50 % lower than those that did not yield. Molecular dynamics simulations performed on boundaries with and without interstitial-type disconnection loops indicate that the presence of those loops reduce the failure stress.

Ion Transport at Polymer–Argyrodite Interfaces

Wed, 30 Jul 2025 00:00:00 +0000

Solid-state electrolytes, particularly polymer/ceramic composite electrolytes, are emerging as promising candidates for lithium-ion batteries due to their high ionic conductivity and mechanical flexibility. The interfaces that arise between the inorganic and organic materials in these composites play a crucial role in ion transport mechanisms. While lithium ions are proposed to diffuse across or parallel to the interface, few studies have directly examined the quantitative impact of these pathways on ion transport and little is known about how they affect the overall conductivity. Here, we present an atomistic study of lithium-ion (Li⁺) transport across well-defined polymer-argyrodite interfaces. We present a force field for polymer-argyrodite interfacial systems, and we carry out molecular dynamics and enhanced sampling simulations of several composite systems, including poly(ethylene oxide) (PEO)/Li₆PS₅Cl, hydrogenated nitrile butadiene rubber...

Precision Synthesis of a Single Chain Polymorph of a 2D Solid within Single‐Walled Carbon Nanotubes

Wed, 30 Jul 2025 00:00:00 +0000

The discovery and synthesis of atomically precise low-dimensional inorganic materials have led to numerous unusual structural motifs and nascent physical properties. However, access to low-dimensional van der Waals (vdW)-bound analogs of bulk crystals is often limited by chemical considerations arising from structural factors like atomic radii, bonding or coordination, and electronegativity. Using single-walled carbon nanotubes (SWCNTs) as confinement templates, we demonstrate the synthesis of a short-wave infrared-absorbing quasi-1D (q-1D) chain polymorph of Sb₂Te₃ ([Sb₄Te₆]_n) that is structurally and electronically distinct from its 2D counterpart. It is found that the q-1D chain polymorph has both three- and five-coordinate Sb atoms covalently bonded to Te and is thermodynamically stabilized by the electrostatic interaction between the encapsulated chain and the model SWCNT. The complementary experimental and computational...

The origin and control of interstitial impurities in refractory complex concentrated alloys

Wed, 30 Jul 2025 00:00:00 +0000

Interstitial impurities, primarily O and N, inadvertently introduced during the processing of refractory complex concentrated alloys (RCCAs) significantly limit the mechanical properties of the alloys at room temperature. Plasma arc melting (PAM) has facilitated the quest for RCCAs, showcasing remarkable combinations of strength and ductility. In this work, the composition and chemistry of residual gases in the PAM chamber environment during arc melting and the interstitial impurities in elemental feedstocks were analyzed to quantify the origin of O and N during synthesis. Moreover, the thermodynamic mechanisms governing the origin of interstitial impurities in arc-melted MoNbTaW RCCAs were discussed. With an understanding of the mechanisms governing the content of interstitial impurities in RCCAs during PAM, arc-melted MoNbTaW RCCAs with fewer than 100 ppm O were synthesized. The arc-melted MoNbTaW RCCAs were then characterized using electron microscopy and atom probe tomography...

Non‐Uniform Electric Field Manipulation of Chromogenic Peptide Amphiphile Assemblies

Tue, 29 Jul 2025 00:00:00 +0000

This work investigates the influence of dielectrophoretic forces on the structural features and the resulting aggregates of a chromogenic model system, peptide-diacetylene (D₃GV-DA) amphiphiles. Here, we systematically investigate how non-uniform electric fields impact the (i) peptide-directed supramolecular assembly stage and (ii) topochemical photopolymerization stage of polydiacetylenes (PDAs) in a quadrupole-based dielectrophoresis (DEP) device, as well as the (iii) manipulation of D₃GV-DA aggregates in a light-induced DEP (LiDEP) platform. The conformation-dependent chromatic phases of peptide-PDAs are utilized to probe the chain-level effect of DEP exposure after the supramolecular assembly or after the topochemical photopolymerization stage. Steady-state spectroscopic and microscopy analyses show that structural features such as the chirality and morphologies of peptidic 1-D nanostructures are mostly conserved upon DEP exposure, but applying mild,...

Micropatterning Photoconductive Peptide Assemblies on Stiff and Soft Biomaterial Substrates

Tue, 29 Jul 2025 00:00:00 +0000

The propagation of electrical signals in the human heart relies on organized conduction pathways to optimally function and pump blood into the rest of the body. Mimicking this directionality across interconnected myocytes in vitro is currently achieved by patterning the cells themselves, which are often subjected to external stimulatory cues that are rarely localized or have controlled anisotropy. Here, we demonstrate an approach to interface micropatterned optoelectronic peptides with cardiomyocytes, whereby the engineered biomolecular structures dictate the organization of cells in a substrate, while also presenting photocurrent-generating electrodes of defined microscale geometries. To this end, we utilized surface modification strategies that allowed for the creation of stable micropatterns of quaterthiophene-bearing peptide assemblies on both glass (∼GPa range) and gelatin hydrogel (∼20 kPa) substrates that last for multiple days within an aqueous environment. The...

Levelized cost and carbon intensity of solar hydrogen production via water splitting using a scalable and intrinsically safe photocatalytic Z-scheme raceway system

Tue, 22 Jul 2025 00:00:00 +0000

Schematic of photocatalytic type 2 Z-scheme raceway design with hydrogen reactor cylinders floating on an oxygen reactor raceway pool. The raceway concept enables a scalable, low-cost, and low-carbon intensity method of hydrogen production. Generating hydrogen from local energy resources such as solar or wind would unlock a low-carbon energy carrier that could be used to reduce greenhouse gas emissions in sectors such as industry and transportation. Yet, the allocation of new or existing power generation solely to hydrogen production remains contentious due to disputes regarding emissions accounting. Photocatalytic (PC) hydrogen production technologies offer a unique solution, as hydrogen is produced directly from solar energy and water, without the need for electricity generation. However, cost projections for all photocatalytic designs to date have suggested that they are not cost competitive compared to conventional electrolysis systems manufactured at scale. Herein, we offer...

Carbon mineralization pathways in interfacial adsorbed water nanofilms

Thu, 17 Jul 2025 00:00:00 +0000

Abstract: Carbon mineralization in humidified carbon dioxide offers a promising route to mitigate anthropogenic emissions in a world stressed by water security. Despite its technological importance, our understanding of carbonation in water-poor environments lags, as traditional dissolution-precipitation pathways struggle to explain the adsorbed water nanofilm-mediated reactivity. Here, we utilize in operando X-ray diffraction (XRD) and advanced molecular simulations to investigate nanoconfined reactions driving forsterite carbonation, the magnesium-rich olivine. By examining magnesium ion dissolution and transport in atomistic simulations of the forsterite-water-carbon dioxide interface and comparing these with the in operando XRD activation energies, we identify both processes as rate-limiting at saturation. Our simulations reveal a mechanistic view of interfacial carbonation, where dissolution and precipitation are mediated by anomalous quasi two-dimensional diffusion....

Proton Exchange Membrane (PEM) Water Electrolysis: Cell-Level Considerations for Gigawatt-Scale Deployment

Thu, 10 Jul 2025 00:00:00 +0000

Hydrogen produced with no greenhouse gas emissions is termed "green hydrogen" and will be essential to reaching decarbonization targets set forth by nearly every country as per the Paris Agreement. Proton exchange membrane water electrolyzers (PEMWEs) are expected to contribute substantially to the green hydrogen market. However, PEMWE market penetration is insignificant, accounting for less than a gigawatt of global capacity. Achieving substantive decarbonization via green hydrogen will require PEMWEs to reach capacities of hundreds of gigawatts by 2030. This paper serves as an overarching roadmap for cell-level improvements necessary for gigawatt-scale PEMWE deployment, with insights from three well-established hydrogen technology companies included. Analyses will be presented for economies of scale, renewable energy prices, government policies, accelerated stress tests, and component-specific improvements.

Quantum light: creation, integration, and applications

Wed, 2 Jul 2025 00:00:00 +0000

In today's rapidly evolving quantum landscape, the generation and manipulation of quantum light not only represent fundamental challenges but also herald unprecedented opportunities in communication, computing, sensing, and imaging. This special issue brings together a collection of contributions that span the entire journey, from the creation of quantum light using novel materials and emitters to its seamless integration into photonic architectures and eventual deployment in advanced quantum applications. This special issue, "Quantum Light: Creation, Integration, and Applications," features a collection of three review articles, five perspectives, and 23 original research papers, highlighting both the timeliness of the topic and the remarkable breadth and richness of ongoing advancements in the field.

Enabling magnetoelectric spin-orbit logic and memory

Tue, 1 Jul 2025 00:00:00 +0000

The interplay between the spin and charge degrees of freedom is an extremely exciting area of research, from both a fundamental science and an applications perspective, and it has the potential to revolutionize the world of computing. However, realizing this potential requires a multitude of breakthroughs that range from fundamental scientific exploration to practical implementation of these discoveries. In this context, we use a magnetoelectric, spin-orbit-coupled (MESO) device to underscore the critical materials physics challenges, striving to bridge the divide between condensed matter physics and tangible applications. In this review article, through the elucidation of the pivotal role played by magnetoelectric coupling mediated by spin-orbit physics of this device, we aim to catalyze further translational research across the broad materials physics community. We discuss the recent development of MESO and possible routes to solve the existing issues with the materials with...

Colossal enhancement of spin transmission through magnon confinement in an antiferromagnet

Tue, 1 Jul 2025 00:00:00 +0000

Since Felix Bloch's introduction of the concept of spin waves in 1930, magnons (the quanta of spin waves) have been extensively studied in a range of materials for spintronics, particularly for non-volatile logic-in-memory devices. Controlling magnons in conventional antiferromagnets and harnessing them in practical applications, however, remains a challenge. In this letter, we demonstrate highly efficient magnon transport in an LaFeO$_3$/BiFeO$_3$/LaFeO$_3$ all-antiferromagnetic system which can be controlled electrically, making it highly desirable for energy-efficient computation. Leveraging spin-orbit-driven spin-charge transduction, we demonstrate that this material architecture permits magnon confinement in ultrathin antiferromagnets, enhancing the output voltage generated by magnon transport by several orders of magnitude, which provides a pathway to enable magnetoelectric memory and logic functionalities. Additionally, its non-volatility enables ultralow-power logic-in-memory...

Photo-induced force microscopy

Mon, 30 Jun 2025 00:00:00 +0000

Photo-induced force microscopy (PiFM) has emerged as a transformative technique in nanoscale imaging, providing insights into the chemical composition and spatial organization of materials at the nanometre scale. PiFM enables innovation in surface science, geological research, biological studies, materials science, photonics and beyond. Compared with other probe-based spectroscopic methods, the nature of tip–sample interaction in PiFM can offer superior spatial resolution and surface sensitivity. This Primer offers the reader an introduction to the fundamentals of PiFM, discusses the configuration of the method, as well as advanced modalities and modifications, such as ultrahigh vacuum and nonlinear techniques. Results and scenarios are summarized, including those in surface chemistry, biology, polymer science and nanophotonics, offering a unique perspective for researchers across multiple disciplines. The Primer concludes with a discussion of PiFM’s limitations and points of...

Chemical Mapping of Nanoparticle–Ligand Interfaces in Optical Nanocavities

Mon, 30 Jun 2025 00:00:00 +0000

Understanding processes in photon-phonon scattering, absorption, and chemical reactions in optical nanocavities is important for single-molecule sensors, single-photon emitters, and photocatalysis. However, the influence of electromagnetic fields, charge transfer, and molecular geometry is challenging to probe by ensemble-averaged spectroscopic techniques over multiple nanocavities. Photoinduced force microscopy (PiFM), which measures photoinduced polarizability under infrared excitation of a sample in the nanocavity between the scanning probe microscopy tip and sample surface, is used here for simultaneous nanoscale topological and chemical characterization. First-principles density functional theory (DFT) simulations of the vibrational spectra of gold nanoparticle surfaces functionalized with benzenedithiol (Au-BDT) elucidate molecular orientation, charge transfer, and oxidation state for understanding molecular and adatom reconfiguration in optical nanocavities in response...

Atomic‐Scale Mechanisms of Nucleation and Stabilization in CuCrO2 and CuFeO2 Delafossite Thin Films on Al2O3

Mon, 23 Jun 2025 00:00:00 +0000

Abstract Delafossite thin films exhibit a range of intriguing physical properties derived from their layered structure, which consists of alternating noble metal ( A + ) and ( B O 2 − ) sublayers in an AB O 2 stoichiometry. The integration of these properties into functional devices requires the successful epitaxial growth of delafossites as thin films on appropriate substrates. Unfortunately, their unique lattice geometry complicates growth, as different delafossites display variable behavior on the same substrate, often unrelated to lattice mismatch. This suggests the presence of yet unidentified stabilization mechanisms that enable the selective growth of certain delafossites, allowing them to be grown either as films themselves or to be used as buffer layers for subsequent deposition. In this study, advanced scanning transmission electron microscopy (STEM) is employed to investigate the nucleation mechanisms governing the stable growth of Cu‐based delafossites on Al 2 O 3...

Proton-Transfer Kinetics at Liquid–Liquid Interfaces

Tue, 17 Jun 2025 00:00:00 +0000

Proton transfer at electrochemical interfaces is fundamentally important across science and technology, yet kinetic measurements of this elementary step at electrode|electrolyte interfaces are convoluted with other electron-transfer steps and by inhomogeneous electrode surfaces. We use facilitated proton transfer at the interface between two immiscible electrolyte solutions (ITIES) as a platform to study proton-transfer kinetics in the absence of interfacial electron transfer and without the defects at solid|electrolyte interfaces. Diffusion-controlled micropipette voltammetry revealed that 2,6-diphenylpyridine (DPP) facilitates proton transfer across the HCl(aq)|trifluorotoluene interface, while voltammetry at nanopipette-supported interfaces yielded activation-controlled ion-transfer currents. We extract kinetic parameters k_app⁰ and α_app, 3.0 ± 1.8 cm/s and 0.3 ± 0.2, respectively, for DPP-facilitated proton transfer by fitting quasi-reversible...

Morphogenesis of spin cycloids in a noncollinear antiferromagnet

Mon, 9 Jun 2025 00:00:00 +0000

Pattern formation in spin systems with continuous-rotational symmetry (CRS) provides a powerful platform to study emergent complex magnetic phases and topological defects in condensed-matter physics. However, its understanding and correlation with unconventional magnetic order along with high-resolution nanoscale imaging are challenging. Here, we employ scanning nitrogen vacancy (NV) magnetometry to unveil the morphogenesis of spin cycloids at both the local and global scales within a single ferroelectric domain of (111)-oriented BiFeO₃, which is a noncollinear antiferromagnet, resulting in formation of a glassy labyrinthine pattern. We find that the domains of locally oriented cycloids are interconnected by an array of topological defects and exhibit isotropic energy landscape predicted by first-principles calculations. We propose that the CRS of spin-cycloid propagation directions within the (111) drives the formation of the labyrinthine pattern and the associated...

Cost-effective urine recycling enabled by a synthetic osteoyeast platform for production of hydroxyapatite

Tue, 3 Jun 2025 00:00:00 +0000

Recycling human urine offers a sustainable solution to environmental challenges posed by conventional wastewater treatment. While it is possible to recover nutrients like nitrogen and phosphorus from urine, the low economic value of these products limits large-scale adoption. Here, we show that engineered yeast can convert urine into hydroxyapatite (HAp), a high-value biomaterial widely used in bone and dental applications. Inspired by the biological mechanisms of bone-forming cells, we develop a synthetic yeast platform osteoyeast, which uses enzymes to break down urea and increase the pH of the surrounding environment. This triggers the yeast vacuoles to accumulate calcium and phosphate as amorphous calcium phosphate, which is then secreted in vesicles and crystallized into HAp. We achieve HAp production at titers exceeding 1 g/L directly from urine. Techno-economic analysis demonstrates that this process offers clear economic and environmental advantages, making it a compelling...

Predicting Pulsed-Laser Deposition SrTiO3 Homoepitaxy Growth Dynamics Using High-Speed Reflection High-Energy Electron Diffraction

Wed, 21 May 2025 00:00:00 +0000

Pulsed-laser deposition (PLD) is a powerful technique for growing complex oxides with controlled stoichiometry. To understand growth dynamics therein, it is common to leverage in situ spectroscopies, such as reflection high-energy electron diffraction (RHEED), to monitor surface crystallinity. Most commercial systems rely on video-rate cameras operating at 60-120 Hz that lack sufficient temporal resolution to capture growth dynamics at practical deposition frequencies. Here, a high-speed platform to record in situ dynamics via RHEED at >500 Hz is implemented. An open-source analysis package is designed to fit diffraction spots to 2D Gaussians, allowing single-pulse surface reconstruction kinetics extraction. Using homoepitaxially deposited (001)-oriented SrTiO₃ as a model system, we demonstrate how high-speed RHEED can provide real-time insight into growth processes obscured by slower acquisition systems. By fitting the single-pulse intensity to a set...

JPL: Designing Crushable Lattices for Terrestrial Hard Impactors

Fri, 16 May 2025 00:00:00 +0000

As space exploration continues to evolve, researchers have been investigating ways to develop low-cost landing systems. Lattice structures are an attractive option for reducing costs during terrestrial landings due to their lightweight character and energy absorption capacity. The ability to produce complex geometries, specifically lightweight lattice structures, makes additive manufacturing an attractive method for producing energy absorbing lattices. During this project, various stereolithography 3D printed lattice structures were designed, manufactured, and tested for their energy absorption capacities. The findings from this study could significantly advance low-cost, high-performance landing solutions for future terrestrial missions, enabling more efficient space exploration.

Epitaxial strain tuning of Er3+ in ferroelectric thin films

Mon, 12 May 2025 00:00:00 +0000

Er 3 + color centers are promising candidates for quantum science and technology due to their long electron and nuclear spin coherence times, as well as their desirable emission wavelength. By selecting host materials with suitable, controllable properties, we introduce new parameters that can be used to tailor the Er3+ emission spectrum. PbTiO3 is a well-studied ferroelectric material with known methods of engineering different domain configurations through epitaxial strain. By distorting the structure of Er3+-doped PbTiO3 thin films, we can manipulate the crystal fields around the Er3+ dopant. This is resolved through changes in the Er3+ resonant fluorescence spectra, tying the optical properties of the defect directly to the domain configurations of the ferroelectic matrix. Additionally, we are able to resolve a second set of peaks for films with in-plane ferroelectric polarization. We hypothesize these results to be due to either the Er3+ substituting different sites of the...

Low-Field Regime of Magnon Transport in PLD-Grown YIG Films

Mon, 12 May 2025 00:00:00 +0000

The diffusive propagation of magnons in the archetypal magnetic insulator yttrium iron garnet (YIG) is being actively explored for low-power and low-loss data communication. However, operation under external magnetic fields reduces the magnon diffusion length and attenuates the voltage amplitude at measurement terminals of magnonic devices. Here, we explore the low-field and field-free regime of diffusive magnon transport in YIG films, demonstrating that the field-induced suppression of magnon diffusion length can be fully inhibited only at the zero-field limit. Even a modest field of 10 mT attenuates the nonlocal spin voltage by ∼20% in an ∼1 μm long transport channel. We further identify the often overlooked in-plane uniaxial magnetic anisotropy as the dominant factor governing magnon transport in the low-field regime. Using Stoner-Wohlfarth macrospin simulations, we quantify the anisotropy parameters and reveal a 10-fold enhancement at low temperatures, a key finding for field-free...

Transient Slope: A Metric for Assessing Heterogeneity from the Dielectrophoresis Spectrum

Fri, 9 May 2025 00:00:00 +0000

Cellular heterogeneity, an inherent feature of biological systems, plays a critical role in processes such as development, immune response, and disease progression. Human mesenchymal stem cells (hMSCs) exemplify this heterogeneity due to their multi-lineage differentiation potential. However, their inherent variability complicates clinical use, and there is no universally accepted method for detecting and quantifying cell population heterogeneity. Dielectrophoresis (DEP) has emerged as a powerful electrokinetic technique for characterizing and manipulating cells based on their dielectric properties, offering label-free analysis capabilities. Quantitative information from the DEP spectrum, such as transient slope, measure cells’ transition between negative and positive DEP behaviors. In this study, we employed DEP to estimate transient slope of various cell populations, including relatively homogeneous HEK-293 cells, heterogeneous hMSCs, and cancer cells (PC3 and DU145). Our analysis...

Electrical Phenotyping of Aged Human Mesenchymal Stem Cells Using Dielectrophoresis

Fri, 9 May 2025 00:00:00 +0000

Human mesenchymal stem cells (hMSCs) are widely used in regenerative medicine, but large-scale in vitro expansion alters their function, impacting proliferation and differentiation potential. Currently, a predictive marker to assess these changes is lacking. Here, we used dielectrophoresis (DEP) to characterize the electrical phenotype of hMSCs derived from bone marrow (BM), adipose tissue (AT), and umbilical cord (UC) as they aged in vitro from passage 4 (P4) to passage 9 (P9). The electrical phenotype was defined by the DEP spectra, membrane capacitance, and cytoplasm conductivity. Cell morphology and size, growth characteristics, adipogenic differentiation potential, and osteogenic differentiation potential were assessed alongside label-free biomarker membrane capacitance and cytoplasm conductivity. Differentiation was confirmed by histological staining and RT-qPCR. All hMSCs exhibited typical morphology, though cell size varied, with UC-hMSCs displaying the largest variability...

Phenotypic Characterization of 2D and 3D Prostate Cancer Cell Systems Using Electrical Impedance Spectroscopy

Fri, 9 May 2025 00:00:00 +0000

Prostate cancer is the second leading cause of death in men. A challenge in treating prostate cancer is overcoming cell plasticity, which links cell phenotype changes and chemoresistance. In this work, a microfluidic device coupled with electrical impedance spectroscopy (EIS), an electrode-based cell characterization technique, was used to study the electrical characteristics of phenotype changes for (1) prostate cancer cell lines (PC3, DU145, and LNCaP cells), (2) cells grown in 2D monolayer and 3D suspension cell culture conditions, and (3) cells in the presence (or absence) of the anti-cancer drug nigericin. To validate observations of phenotypic change, we measured the gene expression of two epithelial markers, E-cadherin (CDH1) and Tight Junction Protein 1 (ZO-1). Our results showed that PC3, DU145, and LNCaP cells were discernible with EIS. Secondly, moderate phenotype changes based on differences in cell culture conditions were detected with EIS and supported by the gene...

Electrical Impedance Spectroscopy as a Tool to Detect the Epithelial to Mesenchymal Transition in Prostate Cancer Cells

Fri, 9 May 2025 00:00:00 +0000

Prostate cancer (PCa) remains a significant health threat, with chemoresistance and recurrence posing major challenges despite advances in treatment. The epithelial to mesenchymal transition (EMT), a biochemical process where cells lose epithelial features and gain mesenchymal traits, is linked to chemoresistance and metastasis. Electrical impedance spectroscopy (EIS), a novel label-free electrokinetic technique, offers promise in detecting cell phenotype changes. In this study, we employed EIS to detect EMT in prostate cancer cells (PCCs). PC3, DU145, and LNCaP cells were treated with EMT induction media for five days. EIS characterization revealed unique impedance spectra correlating with metastatic potential, distinguishing DU145 EMT+ and EMT- cells, and LNCaP EMT+ and EMT- cells (in combination with dielectrophoresis), with comparisons made to epithelial and mesenchymal controls. These changes were supported by shifts in electrical signatures, morphologies, and protein expression,...

Divergent evolution of slip banding in CrCoNi alloys

Sat, 26 Apr 2025 00:00:00 +0000

Metallic materials under high stress often exhibit deformation localization, manifesting as slip banding. Over seven decades ago, Frank and Read introduced the well-known model of dislocation multiplication at a source, explaining slip band formation. Here, we reveal two distinct types of slip bands (confined and extended) in compressed CrCoNi alloys through multi-scale testing and modeling from microscopic to atomic scales. The confined slip band, characterized by a thin glide zone, arises from the conventional process of repetitive full dislocation emissions at Frank–Read source. Contrary to the classical model, the extended band stems from slip-induced deactivation of dislocation sources, followed by consequent generation of new sources on adjacent planes, leading to rapid band thickening. Our findings provide insights into atomic-scale collective dislocation motion and microscopic deformation instability in advanced structural materials.

Machine Learning‐Guided Discovery of Factors Governing Deformation Twinning in Mg–Y Alloys

Thu, 24 Apr 2025 00:00:00 +0000

Magnesium (Mg) alloys are promising lightweight structural materials whose limited strength and room-temperature ductility limit applications. Precise control of deformation-induced twinning through microstructural alloy design is being investigated to overcome these deficiencies. Motivated by the need to understand and control twin formation during deformation in Mg alloys, a series of magnesium-yttrium (Mg–Y) alloys are investigated using electron backscatter diffraction (EBSD). Analysis of EBSD maps produces a large dataset of microstructural information for >40000 grains. To quantitatively determine how processing parameters and microstructural features are correlated with twin formation, interpretable machine learning (ML) is employed to statistically analyze the individual effects of microstructural features on twinning. An ML classifier is trained to predict the likelihood of twin formation, given inputs including grain microstructural information and synthesis...

Room-temperature multiferroicity in sliding van der Waals semiconductors with sub-0.3 V switching

Thu, 24 Apr 2025 00:00:00 +0000

The search for van der Waals (vdW) multiferroic materials has been challenging but also holds great potential for the next-generation multifunctional nanoelectronics. The group-IV monochalcogenide, with an anisotropic puckered structure and an intrinsic in-plane polarization at room temperature, manifests itself as a promising candidate with coupled ferroelectric and ferroelastic order as the basis for multiferroic behavior. Unlike the intrinsic centrosymmetric AB stacking, we demonstrate a multiferroic phase of tin selenide (SnSe), where the inversion symmetry breaking is maintained in AA-stacked multilayers over a wide range of thicknesses. We observe that an interlayer-sliding-induced out-of-plane (OOP) ferroelectric polarization couples with the in-plane (IP) one, making it possible to control out-of-plane polarization via in-plane electric field and vice versa. Notably, thickness scaling yields a sub-0.3 V ferroelectric switching, which promises future low-power-consumption...

Ferroelectric tunnel junctions integrated on semiconductors with enhanced fatigue resistance

Thu, 24 Apr 2025 00:00:00 +0000

Oxide-based ferroelectric tunnel junctions (FTJs) show promise for nonvolatile memory and neuromorphic applications, making their integration with existing semiconductor technologies highly desirable. Furthermore, resistance fatigue in current silicon-based integration remains a critical issue. Understanding this fatigue mechanism in semiconductor-integrated FTJ is essential yet unresolved. Here, we systematically investigate the fatigue performance of ultrathin bismuth ferrite BiFeO₃ (BFO)-based FTJs integrated with various semiconductors. Notably, the BFO/gallium arsenide FTJ exhibits superior fatigue resistance characteristics (>10⁸ cycles), surpassing the BFO/silicon FTJ (>10⁶ cycles) and even approaching epitaxial oxide FTJs (>10⁹ cycles). The atomic-scale fatigue mechanism is revealed as lattice structure collapse caused by oxygen vacancy accumulation in BFO near semiconductors after repeated switching. The enhanced fatigue-resistant...

Opportunities for Nanomaterials in Stretchable and Free‐Form Displays

Mon, 21 Apr 2025 00:00:00 +0000

Stretchable and free-form displays receive significant attention as they hold immense potential for revolutionizing future display technologies. These displays are designed to conform to irregular surfaces and endure mechanical strains, making them well suited for applications in wearable electronics, biomedical devices, and interactive displays. Traditional light-emitting devices typically employ brittle inorganic and metallic materials, which are not conducive to stretchability. However, replacing these nonflexible components with flexible/stretchable nanomaterials, soft organic materials, or their composites improves the overall flexibility and stretchability of devices. In this review, the roles and opportunities of nanomaterials, such as thin films, 1D nanofibrous materials, and micro/nanoparticles, are highlighted for enhancing the stretchability and overall performance of various types of light-emitting devices. By leveraging the unique mechanical and electrical properties...

Durability of Pt‐Alloy Catalyst for Heavy‐Duty Polymer Electrolyte Fuel Cell Applications under Realistic Conditions

Thu, 10 Apr 2025 00:00:00 +0000

Abstract As an emerging technology, polymer electrolyte fuel cells (PEFCs) powered by clean hydrogen can be a great source of renewable power generation with flexible utilization because of high gravimetric energy density of hydrogen. To be used in real‐life applications, PEFCs need to maintain their performance for long‐term use under a wide range of conditions. Therefore, it's important to understand the degradation of the PEFC under protocols that are closely related to the catalyst lifetime. Alloying Pt with transitional metal improves catalyst activity. It is also crucial to understand Pt alloys degradation mechanisms to improve their durability. To study durability of Pt alloys, accelerated stress tests (ASTs) are performed on Pt−Co catalyst supported on two types of carbon. Two different AST protocols were being studied: Membrane Electrolyte Assembly (MEA) AST based on the protocol introduced by the Million Mile Fuel Cell Truck consortium in 2023 and Catalyst AST, adopted...

Hierarchical Assembly of Conductive Fibers from Coiled-Coil Peptide Building Blocks

Thu, 10 Apr 2025 00:00:00 +0000

Biology provides many sources of inspiration for synthetic and multifunctional nanomaterials. Naturally evolved proteins exhibit specialized, sequence-defined functions and self-assembly behavior. Recapitulating their molecularly defined self-assembly behavior, however, is challenging in de novo proteins. Peptides, on the other hand, represent a more well-defined and rationally designable space with the potential for sequence-programmable, stimuli-responsive design for structure and function, making them ideal building blocks of bioelectronic interfaces. In this work, we design peptides that exhibit stimuli-responsive self-assembly and the capacity to transport electrical current over micrometer-long distances. A lysine-lysine (KK) motif inserted at solvent-exposed positions of a coiled-coil-forming peptide sequence introduces pH-dependent control over a transition from unordered to α-helical peptide structure. The ordered state of the peptide serves as a building block...

Nonlinear Nanophotonics: feature issue introduction

Mon, 7 Apr 2025 00:00:00 +0000

We introduce the feature issue of Optical Materials Express on Nonlinear Nanophotonics. This collection highlights recent advances in the design, fabrication, and application of nanophotonic systems that exploit nonlinear optical phenomena, spanning topics from high-harmonic generation and soliton microcombs to plasmon-enhanced emission and mid-infrared nonlinear optics.

Fluorescence Lifetime Imaging Detects Long-Lifetime Signal Associated with Reduced Pyocyanin at the Surface of Pseudomonas aeruginosa Biofilms and in Cross-Feeding Conditions

Mon, 7 Apr 2025 00:00:00 +0000

Understanding bacterial physiology in real-world environments requires noninvasive approaches and is a challenging yet necessary endeavor to effectively treat infectious disease. Bacteria evolve strategies to tolerate chemical gradients associated with infections. The DIVER (Deep Imaging Via Enhanced Recovery) microscope can image autofluorescence and fluorescence lifetime throughout samples with high optical scattering, enabling the study of naturally formed chemical gradients throughout intact biofilms. Using the DIVER, a long fluorescent lifetime signal associated with reduced pyocyanin, a molecule for electron cycling in low oxygen, was detected in low-oxygen conditions at the surface of Pseudomonas aeruginosa biofilms and in the presence of fermentation metabolites from Rothia mucilaginosa, which cocolonizes infected airways with P. aeruginosa. These findings underscore the utility of the DIVER microscope and fluorescent lifetime for noninvasive studies...

Evidence of cooperative effect on the enhanced superconducting transition temperature at the FeSe/SrTiO3 interface

Fri, 4 Apr 2025 00:00:00 +0000

At the interface between monolayer FeSe films and SrTiO3 substrates the superconducting transition temperature (Tc) is unexpectedly high, triggering a surge of excitement. The mechanism for the Tc enhancement has been the central question, as it may present a new strategy for seeking out higher Tc materials. To reveal this enigmatic mechanism, by combining advances in high quality interface growth, 16O ↔$$\leftrightarrow$$18O isotope substitution, and extensive data from angle resolved photoemission spectroscopy, we provide striking evidence that the high Tc in FeSe/SrTiO3 is the cooperative effect of the intrinsic pairing mechanism in the FeSe and interactions between the FeSe electrons and SrTiO3 phonons. Furthermore, our results point to the promising prospect that similar cooperation between different Cooper pairing channels may be a general framework to understand and design high-temperature superconductors.

Evolution of spin excitations from bulk to monolayer FeSe

Fri, 4 Apr 2025 00:00:00 +0000

In ultrathin films of FeSe grown on SrTiO3 (FeSe/STO), the superconducting transition temperature Tc is increased by almost an order of magnitude, raising questions on the pairing mechanism. As in other superconductors, antiferromagnetic spin fluctuations have been proposed to mediate SC making it essential to study the evolution of the spin dynamics of FeSe from the bulk to the ultrathin limit. Here, we investigate the spin excitations in bulk and monolayer FeSe/STO using resonant inelastic x-ray scattering (RIXS) and quantum Monte Carlo (QMC) calculations. Despite the absence of long-range magnetic order, bulk FeSe displays dispersive magnetic excitations reminiscent of other Fe-pnictides. Conversely, the spin excitations in FeSe/STO are gapped, dispersionless, and significantly hardened relative to its bulk counterpart. By comparing our RIXS results with simulations of a bilayer Hubbard model, we connect the evolution of the spin excitations to the Fermiology of the two systems...

Improving the fast-charging capability of NbWO-based Li-ion batteries

Thu, 3 Apr 2025 00:00:00 +0000

The discovery of Nb-W-O materials years ago marks the milestone of charging a lithium-ion battery in minutes. Nevertheless, for many applications, charging lithium-ion battery within one minute is urgently demanded, the bottleneck of which largely lies in the lack of fundamental understanding of Li+ storage mechanisms in these materials. Herein, by visualizing Li+ intercalated into representative Nb16W5O55, we find that the fast-charging nature of such material originates from an interesting rate-dependent lattice relaxation process associated with the Jahn-Teller effect. Furthermore, in situ electron microscopy further reveals a directional, [010]-preferred Li+ transport mechanism in Nb16W5O55 crystals being the “bottleneck” toward fast charging that deprives the entry of any desolvated Li+ through the prevailing non-(010) surfaces. Hence, we propose a machine learning-assisted interface engineering strategy to swiftly collect desolvated Li+ and relocate them to (010) surfaces...

Fluorescence Lifetime Imaging Detects Long-Lifetime Signal Associated with Reduced Pyocyanin at the Surface of Pseudomonas aeruginosa Biofilms and in Cross-Feeding Conditions

Thu, 3 Apr 2025 00:00:00 +0000

Unravelling the structure-stability interplay of O3-type layered sodium cathode materials via precision spacing engineering

Wed, 2 Apr 2025 00:00:00 +0000

The O3-type layered oxide represents a highly promising candidate for sodium-ion batteries (SIBs). However, the intrinsic stability law of these cathodes remains elusive due to the complex phase transition mechanism and migration of transition metal (TM) ions. Here, we underscore how the ratio between the spacings of alkali metal layer and TM layer (R = dO-Na-O/dO-TM-O) plays a critical role in determining the structural stability and the corresponding electrochemical performance. We design a peculiar family of NaxMn0.4Ni0.3Fe0.15Li0.1Ti0.05O2 (0.55 ≤ x ≤ 1) composition that is thermodynamically stable as an O3-type structure even when R is as high as 1.969, far exceeding 1.62 that normal O3-type structures can reach at most. The high R-value puts the O3 cathode in the preparatory stage for the O3-P3 phase transition, resulting in a rapid yet smooth phase transition process. It also induces a significantly stretched interstitial tetrahedral structure to the Na layer, thus effectively...

Performance Tuning of Polarizable Gaussian Multipole Model in Molecular Dynamics Simulations

Tue, 1 Apr 2025 00:00:00 +0000

Molecular dynamics (MD) simulations are essential for understanding molecular phenomena at the atomic level, with their accuracy largely dependent on both the employed force field and sampling. Polarizable force fields, which incorporate atomic polarization effects, represent a significant advancement in simulation technology. The polarizable Gaussian multipole (pGM) model has been noted for its accurate reproduction of ab initio electrostatic interactions. In this study, we document our effort to enhance the computational efficiency and scalability of the pGM simulations within the AMBER framework using MPI (message passing interface). Performance evaluations reveal that our MPI-based pGM model significantly reduces runtime and scales effectively while maintaining computational accuracy. Additionally, we investigated the stability and reliability of the MPI implementation under the NVE simulation ensemble. Optimal Ewald and induction parameters for the pGM model are also...

Anomalous correlation effects and unique phase diagram of electron-doped FeSe revealed by photoemission spectroscopy

Fri, 28 Mar 2025 00:00:00 +0000

FeSe layer-based superconductors exhibit exotic and distinctive properties. The undoped FeSe shows nematicity and superconductivity, while the heavily electron-doped KxFe2−ySe2 and single-layer FeSe/SrTiO3 possess high superconducting transition temperatures that pose theoretical challenges. However, a comprehensive study on the doping dependence of an FeSe layer-based superconductor is still lacking due to the lack of a clean means of doping control. Through angle-resolved photoemission spectroscopy studies on K-dosed thick FeSe films and FeSe0.93S0.07 bulk crystals, here we reveal the internal connections between these two types of FeSe-based superconductors, and obtain superconductivity below ∼46 K in an FeSe layer under electron doping without interfacial effects. Moreover, we discover an exotic phase diagram of FeSe with electron doping, including a nematic phase, a superconducting dome, a correlation-driven insulating phase and a metallic phase. Such an anomalous phase diagram...

Understanding Performance Limitation of Liquid Alkaline Water Electrolyzers

Tue, 25 Mar 2025 00:00:00 +0000

Liquid alkaline water electrolyzers (LAWEs), being the most commercially mature electrolysis technology, play a pivotal role in large-scale hydrogen production. However, LAWEs suffer from low operational efficiency, primarily due to un-optimized electrode structure and chemical compositions. Thus, we investigated how various electrode configurations could impact LAWE performance. Our results show that Ni felt electrodes outperform the conventional Ni foam thanks to improved electrochemical active surface area (ECSA) and preferred electrode surface structure that minimizes the micro-gaps in between the electrode and separator. By comparing the stainless steel (SS) felt electrodes with Ni felt electrodes, SS not only shows better oxygen evolution reaction activity but also improved hydrogen evolution reaction activity, which is less studied in the literature. We also show that a bilayer structure with small pore radius facing the separator could further improve LAWE performance...

Photoelectrochemical characterization of infrared-absorbing osmium-polypyridyl dyes bound to TiO2