Feed aggregator

Nature Materials, Published online: 03 May 2024; doi:10.1038/s41563-024-01892-2

The shape of things

Nature Materials, Published online: 03 May 2024; doi:10.1038/s41563-024-01861-9

A wide range of zero-dimensional powders can be converted into versatile, high-performance one-dimensional micro-/nanofibres by using two-dimensional cellulose sheets as a mediator, preserving the particles’ nanostructural features and acting as building blocks for complex geometric shapes to satisfy application requirements.

Nature Materials, Published online: 03 May 2024; doi:10.1038/s41563-024-01869-1

‘Two colour’ pump–probe experiments on yttrium iron garnet discs demonstrate how to harness dissipation of magnetic oscillations. This may have important implications for the use of magnetic materials for information processing.

Nature Materials, Published online: 03 May 2024; doi:10.1038/s41563-024-01902-3

A synthesis method for large-scale conjugated polymers as well as studies under operational conditions show that research on organic mixed ionic–electronic conductors continues to progress.

Nature Materials, Published online: 03 May 2024; doi:10.1038/s41563-024-01881-5

Physical vapour deposition of small-molecule glass formers onto soft substrates enhances the local dynamics at the top free surface, leading to the formation of denser glasses and providing access to states deeper in the potential energy landscape.

Nature Materials, Published online: 03 May 2024; doi:10.1038/s41563-024-01872-6

Strong bulk van der Waals materials can be created from water-mediated densification of two-dimensional nanosheets by near-room-temperature moulding, establishing a pathway for the energy-efficient fabrication of a wide range of bulk van der Waals materials and even composites for various applications.

Nature Materials, Published online: 03 May 2024; doi:10.1038/s41563-024-01863-7

Modified Suzuki–Miyaura polymerization procedures provide a scalable and reproducible route to regioregular conjugated polymers.

Nature Energy, Published online: 03 May 2024; doi:10.1038/s41560-024-01526-6

Achieving good electrical contact without damaging underlying layers is critical to the performance of photovoltaic modules. Research now reports a silver electrode embedded into a polymer matrix and a silver/chromium protection layer, enabling over 14%-efficient flexible organic photovoltaic modules with improved stability under illumination.

Nature Materials, Published online: 03 May 2024; doi:10.1038/s41563-024-01899-9

Degradation is one of the most common causes of capacity deterioration in high-energy-density cathodes. Rotational stacking faults in layered lithium transition-metal oxides are shown to play a critical role in determining their structural and electrochemical stabilities.

Nature Materials, Published online: 03 May 2024; doi:10.1038/s41563-024-01882-4

Efficient phononic nonlinear processes are demonstrated in an acoustoelectric heterostructure combining a high-mobility semiconductor indium gallium arsenide film heterogeneously integrated onto a lithium niobate thin film.

Abstract

Rechargeable all-solid-state lithium metal batteries (ASSLMBs) utilizing inorganic solid-state electrolytes (SSEs) are promising for electric vehicles and large-scale grid energy storage. However, the Li dendrite growth in SSEs still constrains the practical utility of ASSLMBs. To achieve a high dendrite-suppression capability, SSEs must be chemically stable with Li, possess fast Li transfer kinetics, and exhibit high interface energy. Herein, we design a class of low-cost, eco-friendly, and sustainable oxyhalide-nitride solid electrolytes (ONSEs), denoted as Li x N y I z -qLiOH (where x = 3y + z, 0 ≤ q ≤ 0.75) to fulfil all the requirements. As-prepared oxyhalide-nitride fast conductors demonstrate chemically stable against Li and high interface energy (> 43.08 meV Å−2), effectively restraining Li dendrite growth and the self-degradation at the LMA interfaces. Furthermore, improved thermodynamic oxidation stability of ONSEs (> 3 V versus Li+/Li, 0.45 V for pure Li3N), arising from the increased ionicity of Li-N bonds, contributes to the stability in ASSLMBs. As a proof-of-concept, the optimized ONSEs possess high ionic conductivity of 0.52 mS cm−1 and achieve long-term cycling of Li||Li symmetric cell for over 500 h. When coupled with the Li3InCl6 SSE for high-voltage cathodes, the bi-layer oxyhalide-nitride/Li3InCl6 electrolyte imparts 90% capacity retention over 500 cycles for Li||1 mAh cm−2 LiCoO2 cells. This work heralds a class of stable ONSEs with exceptional Li compatibility, good oxidative resistance, as well as high ionic conductivity to significantly ASSLMBs advance.

This article is protected by copyright. All rights reserved

Abstract

Slippery surfaces, which originate in nature with special wettability, have drawn a great deal of attention for both fundamental research and practical applications in a variety of fields due to their unique characteristics of super-low liquid friction and adhesion. Although the research of bioinspired slippery surfaces is in its infancy, it is a rapidly growing and enormously promising field. Herein, we present a systematic review of recent progress in bioinspired slippery surfaces, beginning with a brief introduction of several typical creatures with slippery property in nature. Subsequently, a detailed discussion the basic concepts of the wetting, friction and drag from micro and macro aspects and focus on the underlying slippery mechanism. We next summarize state-of-the-art developments of the three categories of slippery surfaces of air-trapped, liquid-infused and liquid-like slippery surfaces, including materials, design principles and preparation methods of slippery surfaces and highlight the emerging applications. Finally, the current challenges and future prospects of various slippery surfaces are addressed.

This article is protected by copyright. All rights reserved

Abstract

The processing of visual information occurs mainly in the retina, and the retinal preprocessing function greatly improves the transmission quality and efficiency of visual information. The artificial retina system provides a promising path to efficient image processing. Here, we propose graphene/InSe/h-BN heterogeneous structure, which exhibits negative and positive photoconductance effects by altering the strength of a single wavelength laser. Moreover, we present a modified theoretical model based on the power-dependent photoconductivity effect of laser: Iph=−mPα1+nPα2$\rm I_{\rm ph}\,=\,\rm {-mP}^{\rm \alpha _{1}} + \rm {nP}^{\rm \alpha _{2}}$, which can reveal the internal physical mechanism of negative/positive photoconductance effects. The present two-dimensional (2D) structure design allows the field effect transistor (FET) to exhibit excellent photoelectric performance (RNPC = 1.1× 104 A/w, RPPC = 13 A/w) and performance stability. Especially, the retinal pretreatment process is successfully simulated based on the negative and positive photoconductive effects. Moreover, the pulse signal input improves the device responsivity by 167%, and the transmission quality and efficiency of the visual signal can also be enhanced. This work provides a new design idea and direction for the construction of artificial vision, and lay a foundation for the integration of the next generation of optoelectronic devices.

This article is protected by copyright. All rights reserved

Abstract

Biological olfaction relies on a large number of receptors that function as sensors to detect gaseous molecules. It has been challenging to realize artificial olfactory systems that contain similarly large numbers of sensory materials. We show that combinatorial materials processing with vapor deposition can be used to fabricate large arrays of distinct chemiresistive sensing materials. By combining these with light-emitting diodes, we obtain an array of chemiresistively-modulated light-emitting diodes, or ChemLEDs, that permit a simultaneous optical read-out in response to an analyte. The optical nose uses a common voltage source and ground for all sensing elements and thus eliminates the need for complex wiring of individual sensors. Our optical nose contains one hundred ChemLEDs and generates unique light patterns in response to gases and their mixtures. Optical pattern recognition methods enable the quantitative prediction of the corresponding concentrations and compositions, thereby paving the way for massively parallel artificial olfactory systems. ChemLEDs open the possibility to explore demanding gas sensing applications, including in environmental, food quality monitoring, and potentially diagnostic settings.

This article is protected by copyright. All rights reserved

Group rings and hyperbolic geometry

Given a closed hyperbolic manifold M, are there lower bounds on the number of k-cells c_k(M) in a cell decomposition in terms of the geometry of the manifold? Gromov showed that if the manifold has injectivity radius at least 10^6 times (n log n), then there are at least n 1-cells, and conjectured that injectivity radius const times log n should be enough. In this talk I will describe a result providing a lower bound on the number of k-cells for each 0 < k < dim (M). The main input is a freedom theorem for ideals in group rings of hyperbolic groups, which also has other applications. Joint work with Thomas Delzant.

• Speaker: Grigori Avramidi (MPIM)
• Wednesday 08 May 2024, 16:00-17:00
• Venue: MR13.
• Series: Differential Geometry and Topology Seminar; organiser: Oscar Randal-Williams.

Add to your calendar or Include in your list

Abstract

Although evidence indicates that the abnormal accumulation of α-synuclein (α-syn) in dopamine neurons of the substantia nigra is the main pathological feature of Parkinson's disease (PD), no compounds that have both α-syn anti-aggregation and α-syn degradation functions have been successful in treating the disease in the clinic. Here, we show that black phosphorus nanosheets (BPNSs) interact directly with α-syn fibrils to trigger their disaggregation for PD treatment. Moreover, BPNSs have a specific affinity for α-syn through van der Waals forces. And BPNSs are found to activate autophagy to maintain α-syn homeostasis, improve mitochondrial dysfunction, reduce reactive oxygen species levels, and rescue neuronal death and synaptic loss in PC12 cells. We have also observed that BPNSs penetrate the blood-brain barrier and protect against dopamine neuron loss, alleviating behavioral disorders in MPTP induced mouse model and hA53T α-syn transgenic mice. Together, our study reveals that BPNSs have the potential as a novel integrated nanomedicine for clinical diagnosis and treatment of neurological diseases.

This article is protected by copyright. All rights reserved

Abstract

An abrupt cessation of antidepressant medication can be challenging due to the appearance of withdrawal symptoms. A slow hyperbolic tapering of an antidepressant, such as citalopram hydrobromide (CHB), can mitigate the withdrawal syndrome. However, there are no viable dosage forms on the market to implement the tapering scheme. A solution using a modular design approach to produce flexible and accurate doses of CHB is proposed. This design consists of two parts: (1) a module with a fixed amount of preloaded CHB in a freeze-dried polymer matrix, and (2) fine-tuning the CHB dose by inkjet printing. A non-contact food-grade printer, used for the first time for printing pharmaceuticals, is modified to allow for accurate printing of the highly concentrated CHB ink on the porous CHB-free or CHB-preloaded modules. The produced modules with submicron precision are bench-marked with commercially available CHB tablets that are manually divided. The proposed tunable modular design (TMD) covers the entire range of doses needed for the tapering (0.5-23.8 mg). The greatest variance is 13% and 88% when comparing TMD and self-tapering, respectively. Self-tapering is proven inaccurate and showcases the need for the TMD to make available accurate and personalized doses to wean off treatment with CHB.

This article is protected by copyright. All rights reserved

Energy Environ. Sci., 2024, Advance Article
DOI: 10.1039/D4EE00349G, Communication Open Access &nbsp This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.Darci K. Collins, Zebulon G. Schichtl, Nathan T. Nesbitt, Ann L. Greenaway, Valentin D. Mihailetchi, Daniel Tune, Emily L. Warren
Demonstration of a new three-terminal semiconductor photoabsorber architecture for photoelectrochemical fuel production that enables protection of the semiconductor in the dark.
To cite this article before page numbers are assigned, use the DOI form of citation above.
The content of this RSS Feed (c) The Royal Society of Chemistry

Interferometric measurements of the 21-cm signal with SKA

The Cosmic Dawn marks the first star formations and preceded the Epoch-of-Reionization, when the Universe underwent a fundamental transformation propelled by the radiation from these first stars and galaxies. Interferometric 21-cm experiments aim to probe redshifted neutral hydrogen signals from these periods, constraining the conditions of the early Universe. The SKA -LOW instrument of the Square Kilometre Array telescope is envisaged to be the largest and most sensitive radio telescope at m and cm wavelengths. In this talk we present a full SKA pipeline that consist of forward modelling and data analysis that were also tested in the SKA Science Data Challenge 3a: Epoch of Reionisation (SKA SDC3a) to process the novel data products expected from the SKA . The forward modelling enables simulation of the astrophysical signals from the Epoch of Reionization and chosen systematic effects of the SKA -LOW. In the analysis part we implement predictive foreground and Bayesian Gaussian Process Regression models alongside a foreground avoidance strategy to isolate the 21-cm signal from that of the astrophysical radio frequency (RF) foregrounds. Together these will determine whether a successful 21-cm detection is possible with the envisaged SKA .

• Speaker: Yuchen Liu and Oscar O'Hara (Cavendish Astrophysics)
• Tuesday 07 May 2024, 11:15-12:00
• Venue: Coffee area, Battcock Centre.
• Series: Hills Coffee Talks; organiser: Charles Walker.

Add to your calendar or Include in your list

Abstract

Ultrapure deep-blue emitters are in high demand for organic light-emitting diodes (OLEDs). Although color coordinates serve as straightforward parameters for assessing color purity, precise control over the maximum wavelength and full-width at half-maximum is necessary to optimize OLED performance, including luminance efficiency and luminous efficacy. Multiple-resonance (MR) emitters are promising candidates for achieving ideal luminescence properties; consequently, a wide variety of MR frameworks have been developed. However, most of these emitters experience a wavelength displacement from the ideal color, which limits their practical applicability. Therefore, a molecular design that is compatible with MR emitters for modulating their energy levels and color output is particularly valuable. Here, we demonstrate that the azepine donor unit induces an appropriate blue-shift in the emission maximum while maintaining efficient MR characteristics, including high photoluminescence quantum yield, narrow emission, and a fast reverse intersystem crossing rate. OLEDs using newly developed MR emitters based on the ν-DABNA framework simultaneously exhibit a high quantum efficiency of ∼30%, luminous efficacy of ∼20 lm W−1, exceptional color purity with Commission Internationale de l’Éclairage coordinates as low as (0.14, 0.06), and notably high operational stability. These results demonstrate unprecedentedly high levels compared with those observed in previously reported deep-blue emitters.

This article is protected by copyright. All rights reserved