Nanoscience News (<front>)

Electrocatalytic liquid HCOOH and NO3 − synthesis of urea with high Faraday efficiency at high current density is successfully achieved by synthesizing the Cu4Pt tandem catalyst loaded on copper foam. The doped Pt sites can enrich liquid HCOOH reactants, promote HCOOH intermolecular dehydration, and form a large number of *CO key intermediates to lay the foundation for subsequent C─N coupling.

Abstract

The formation of urea by electrocatalytic reduction of C1-reactants and NO3 − is an attractive way to store renewable electricity, close the carbon cycle, and eliminate nitrate contaminants from wastewater. Involving insufficient supply of C1 reactants and multiple electron transfers makes the reaction difficult to achieve high Faraday efficiency and high yield at high current density. Here, a urea synthesis approach is presented via electrocatalytic reductive coupling between liquid HCOOH and NO3 − on copper foam (CF) loaded Cu4Pt catalyst with optimized ratios. A urea yield of 40.08 mg h−1 cm−2 is achieved with FE up to 58.1% at a current density of −502.3 mA cm−2, superior to the productivity of previously reported catalysts. No degradation is observed over 120-h continuous operation at such a high yield rate. The highly efficient activity of Cu4Pt/CF can be attributed to the synergetic effect between Pt and Cu sites via tandem catalysis, in which the doped Pt sites enrich liquid HCOOH reactants, promote HCOOH intermolecular dehydration, and form and adsorb large amounts of *CO key intermediates. The Cu sites can generate large quantities of the key intermediate *NH2. The Cu4Pt/CF adsorbed intermediates *CO and *NH2 are the basis for subsequent thermodynamic spontaneous C─N coupling.

An efficient high-entropy strategy is developed to produce 1T-phase quantum sheets of transition-metal disulfides based on controllable introduction of multiple metal atoms with large size differences to retard the sliding of basal plane. The key is the topological conversion of in-plane ordered carbide laminates (i-MAX) compatible with multiple atoms to high-strained high-entropy transition-metal disulfides with 1T phase, which facilely triggers the fracture into 1T-phase quantum sheets during the exfoliation process. The resultant 1T-phase disulfide quantum sheets show high electrocatalytic activities for lithium polysulfides, achieving good electrochemical properties in lithium-sulfur batteries.

Abstract

Quantum sheets of transition-metal dichalcogenides (TMDs) are promising nanomaterials owing to the combination of both 2D nanosheets and quantum dots with distinctive properties. However, the quantum sheets usually possess semiconducting behavior associated with 2H phase, it remains challenging to produce 1T-phase quantum sheets due to the easy sliding of the basal plane susceptible to the small lateral sizes. Here, an efficient high-entropy strategy is developed to produce 1T-phase quantum sheets of transition-metal disulfides based on controllable introduction of multiple metal atoms with large size differences to retard the sliding of basal plane. The key is the topological conversion of in-plane ordered carbide laminates (i-MAX) compatible with multiple atoms to high-entropy transition-metal disulfides with high strains and 1T phase, which facilely triggers the fracture into 1T-phase quantum sheets with average size of 4.5 nm and thickness of 0.7 nm during the exfoliation process. Thus, the 1T-phase disulfide quantum sheets show high electrocatalytic activities for lithium polysulfides, achieving a good rate performance of 744 mAh g−1 at 5 C and a long cycle stability in lithium-sulfur batteries.

This study investigates the internal and external cooling-induced strains in monolayer MoSe2 at cryogenic temperatures, focusing on strain effects arising from thermal expansion coefficient mismatch at 2D-bulk interfaces. Interface engineering demonstrates that compressive strain induces direct-to-indirect bandgap transitions. Notably, hexagonal boron nitride encapsulation effectively mitigates external strain via 2D–2D interfaces, yielding performance comparable to suspended samples.

Abstract

2D materials exhibit unique properties for next-generation electronics and quantum devices. However, their sensitivity to temperature variations, particularly concerning cooling-induced strain, remains underexplored systematically. This study investigates the effects of cooling-induced strain on monolayer MoSe2 at cryogenic temperatures. It is emphasized that the mismatch in thermal expansion coefficients between the material and bulk substrate leads to significant external strain, which superimposes the internal strain of the material. By engineering the material-substrate 2D-bulk interface, the resulting strain conditions are characterized and reveal that substantial compressive strain induces new emission features linked to direct-to-indirect bandgap transition, as confirmed by photoluminescence and transient absorption spectroscopy studies. Finally, it is demonstrated that encapsulation with hexagonal boron nitride can mitigate the external strain by 2D–2D interfaces, achieving results similar to those of suspended samples. The findings address key challenges in quantifying and characterizing strain types across different 2D-bulk interfaces, distinguishing cooling-induced strain effects from other temperature-dependent phenomena, and designing strain-sensitive 2D material devices for extreme temperature conditions.

The epitaxial growth of hexagonal boron nitride (h-BN) multilayer films on graphene, synthesized on a miscut SiC (0001) substrate, is demonstrated using nitrogen plasma-assisted molecular-beam epitaxy. Robust ferroelectricity with switchable out-of-plane polarization via interlayer sliding is supported by theoretical and experimental insights, providing a scalable pathway for integrating ferroelectric vdW materials into advanced 2D devices with diverse functionalities.

Abstract

Ferroelectricity realized in van der Waals (vdW) materials with non-centrosymmetric stacking configurations holds promise for future 2D devices with nonvolatile and reconfigurable functionalities. However, the epitaxial growth of ferroelectric vdW materials often struggles to achieve an energetically unfavorable stacking configuration that enables electric polarization. This challenge is particularly evident when performing heteroepitaxy on another vdW substrate to create versatile and scalable ferroelectric building blocks designed for large-area, atomic-scale thicknesses. Here, epitaxial hexagonal boron nitride (h-BN) multilayer films are successfully grew on single-crystal graphene synthesized on a miscut SiC (0001) substrate. Theoretical calculations illustrate that the moiré-patterned h-BN/graphene hetero-interface intrinsically exhibits polarization, leading to a polarized AB stacking in multilayer h-BN films to minimize the total formation energy, which is validated experimentally by the layer-dependent band dispersions. The as-grown multilayer h-BN layers demonstrated robust, homogeneous ferroelectricity with switchable out-of-plane polarization via interlayer sliding. This study establishes an effective route for stacking-controlled heteroepitaxy, enabling the large-scale integration of vdW materials with ferroelectricity and versatile functionalities, offering a promising platform for next-generation 2D ferroelectric devices.

This perspective provides a systematic discussion on the challenges and solutions in designing materials for intrinsically stretchable organic light-emitting diodes (ISOLEDs). It also highlights prospective challenges and offers insights into the development of highly efficient and stable ISOLEDs for practical applications.

Abstract

Wearable electronics require stretchable displays that can withstand large and repeated mechanical deformation without failure. Intrinsically stretchable organic light-emitting diodes (ISOLEDs) that operate under DC voltage provide promising candidates for wearable display applications. However, the lack of sophisticated stretchable materials and processing techniques suitable for ISOLEDs results in a significant deficit in the efficiency of state-of-the-art ISOLEDs compared to industrial standards. The design of stretchable conducting and semiconducting materials poses a significant challenge because of trade-off relationships between stretchability and properties such as conductivity and charge carrier mobility. To increase the efficiency of ISOLEDs to meet industrial standards, strategies to overcome these trade-offs must be developed. This perspective discusses recent progress and challenges in designing stretchable electrodes, light-emitting materials, transport materials, and potential applications of ISOLEDs. It provides a useful guide in this field to develop efficient ISOLEDs for system-level integration.

Pure Organic red persistent phosphorescent materials, possessing high-temperature resistance and superior tissue penetration, can be efficiently fabricated using a host–guest doping strategy. The triplet-to-triplet Dexter energy transfer process plays a crucial role in modulating the luminescent properties of both the host and the guest. These materials hold promise for applications in advanced information encryption and bioimaging.

Abstract

Organic materials with red persistent phosphorescence hold immense promise for biotechnology due to their excellent tissue permeability and high signal-to-background ratios. However, inefficient spin-orbit coupling, high triplet susceptibility, and narrow energy gapspromoted nonradiative deactivations, pose a formidable obstacle to achieving efficient red phosphorescence. This study addresses these challenges by introducing xanthone (Xan)-based host–guest systems. Utilizing polyaromatic hydrocarbons (PAHs) as guests, efficient red to near-infrared (NIR) phosphorescent materials with ultralong lifetimes and high quantum yields of up to 821 ms and 2.32%, respectively, are successfully developed. Ultrafast spectroscopy and theoretical studies reveal that Dexter energy transfer (DET) is the dominant mechanism responsible for red phosphorescence. This DET process between Xan and PAHs not only effectively utilizes the dark triplet state of the Xan host but also significantly enhances the triplet generation of the PAH guests, transforming them into potent phosphorescent luminophores. Furthermore, the inherent rigidity of Xan and PAHs endows the resulting materials with excellent phosphorescence performance, even at elevated temperatures (e.g., 423 K). This strategy, proven to be general, paves the way for designing efficient red/NIR phosphorescent materials through the DET mechanism, enabling their applications in molecular imaging and advanced high-temperature encryption.

Title to be confirmed

Abstract not available

• Speaker: Manon Thbaut, Ecole polytechnique
• Friday 09 May 2025, 14:00-15:00
• Venue: Oatley 1 Meeting Room, Department of Engineering.
• Series: Engineering - Mechanics and Materials Seminar Series; organiser: div-c.

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Liquid-phase transmission electron microscopy enables visualization of nanoscale processes involving liquid media. Yet, it suffers from beam effects, such as radiolysis of the liquid, sample heating, and membrane charging. This review summarizes beam effect fundamentals, describes modeling and assessment, and illustrates handling strategies. The findings are transferable to other ionizing radiation techniques using, for example, γ- or X-rays.

Abstract

The ionizing radiation harnessed in electron microscopes or synchrotrons enables unique insights into nanoscale dynamics. In liquid-phase transmission electron microscopy (LP-TEM), irradiating a liquid sample with electrons offers access to real space information at an unmatched combination of temporal and spatial resolution. However, employing ionizing radiation for imaging can alter the Gibbs free energy landscape during the experiment. This is mainly due to radiolysis and the corresponding shift in chemical potential; however, experiments can also be affected by irradiation-induced charging and heating. In this review, the state of the art in describing beam effects is summarized, theoretical and experimental assessment guidelines are provided, and strategies to obtain quantitative information under such conditions are discussed. While this review showcases these effects on LP-TEM, the concepts that are discussed here can also be applied to other types of ionizing radiation used to probe liquid samples, such as synchrotron X-rays.

Along the thread of the mosquito ovary: apprehending malarias lost and regained

Abstract not available

• Speaker: Ann Kelly (University of Oxford)
• Tuesday 25 February 2025, 17:00-18:30
• Venue: Seminar Room 1, Department of History and Philosophy of Science.
• Series: History of Modern Medicine and Biology; organiser: Nick Hopwood.

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2025 Scott Lectures - Lecture 3 Title tbc

Abstract not available

• Speaker: Professor Mikhail Lukin, Harvard University
• Thursday 06 March 2025, 11:00-12:00
• Venue: Ray Dolby Auditorium, Ray Dolby Centre, Cavendish Laboratory, JJ Thomson Avenue, CB3 0US.
• Series: Scott Lectures; organiser: Leona Hope-Coles.

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2025 Scott Lectures - Lecture 1 Title tbc

Abstract not available

Drinks and nibbles will be served after the lecture

• Speaker: Professor Mikhail Lukin, Harvard University
• Monday 03 March 2025, 16:00-17:00
• Venue: Ray Dolby Auditorium, Ray Dolby Centre, Cavendish Laboratory, JJ Thomson Avenue, CB3 0US.
• Series: Scott Lectures; organiser: Leona Hope-Coles.

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2025 Scott Lectures - Lecture 2 Title tbc

Abstract not available

Drinks and nibbles will be served after the lecture

• Speaker: Professor Mikhail Lukin, Harvard University
• Wednesday 05 March 2025, 16:00-17:00
• Venue: Ray Dolby Auditorium, Ray Dolby Centre, Cavendish Laboratory, JJ Thomson Avenue, CB3 0US.
• Series: Scott Lectures; organiser: Leona Hope-Coles.

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Title to be confirmed

=== Hybrid talk ===

Join Zoom Meeting https://cam-ac-uk.zoom.us/j/87143365195?pwd=SELTNkOcfVrIE1IppYCsbooOVqenzI.1

Meeting ID: 871 4336 5195

Passcode: 541180

POSTPONED

• Speaker: Andrei Popescu (University of Sheffield)
• Thursday 06 March 2025, 17:00-18:00
• Venue: MR14 Centre for Mathematical Sciences.
• Series: Formalisation of mathematics with interactive theorem provers ; organiser: Anand Rao Tadipatri.

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Nature Nanotechnology, Published online: 21 February 2025; doi:10.1038/s41565-025-01867-7

Delivering therapeutics to the brain is challenging because of the hard-to-cross blood–brain barrier. Here, the authors show that HER3, which is expressed on the surface of many metastatic tumours, is associated with the brain endothelium and can drive accumulation of HER3-targeted nanoparticles within the brain, for therapy against HER3-positive tumours.

Nature Nanotechnology, Published online: 21 February 2025; doi:10.1038/s41565-025-01865-9

Neutron scattering on a model system of highly concentrated solutions of charged carbon nanotubes reveals a strong solvent ordering up to ∼40 Å around the charged nanoscale surface.

Nature Materials, Published online: 21 February 2025; doi:10.1038/s41563-025-02151-8

A method is reported to create chiral rolls from two-dimensional atomic layers such as graphene with controlled rolling angles, which show optical activity and spin-selective transport dependent on the chiral lattice structures.

Nature Materials, Published online: 21 February 2025; doi:10.1038/s41563-025-02157-2

The high-frequency elastic response reveals interpenetrated and polycatenated structures in DNA nanostar network materials.

Nature Materials, Published online: 21 February 2025; doi:10.1038/s41563-025-02133-w

Elasticity is ubiquitous in everyday life, but the molecular origin of the restoring force remains elusive. Here the authors use a series of density functional theory calculations to understand how interaction energies change as a result of the bending of molecular crystals.

Nature Materials, Published online: 21 February 2025; doi:10.1038/s41563-025-02127-8

A wax-aided immersion methodology is developed to yield graphene rolls with tunable chiral angles; these graphene rolls exhibit promising chiral electronic properties beyond those of other carbon allotropes.

Nature Energy, Published online: 21 February 2025; doi:10.1038/s41560-025-01715-x

Increasing solar photovoltaic and wind generation capacity beyond European 2030 targets could make electricity prices more stable, with reductions in sensitivity to fluctuations in the price of natural gas possibly outweighing the increasing influence of weather effects. Energy policies should account for the macroeconomic benefits of more stable energy prices as an important motivation for the deployment of renewables, in addition to their contribution to the mitigation of climate change.