Nanoscience News (<front>)

Nature Energy, Published online: 09 June 2025; doi:10.1038/s41560-025-01790-0

Across four countries, more people agree with misinformation statements about electic vehicles than disagree with them, and conspiracist mentality is the strongest predictor of this agreement. Interactions with artificial intelligence show promise in reducing misinformation agreement.

Nature Energy, Published online: 09 June 2025; doi:10.1038/s41560-025-01791-z

The passivation of surface defects is critical in perovskite photovoltaics yet challenging to implement in practice. Wang et al. show that fluorinated isopropanol allows the use of a high concentration of passivator molecules, ensuring the complete passivation of defects.

Nature Energy, Published online: 09 June 2025; doi:10.1038/s41560-025-01787-9

Ultrapure water is usually used as a feedstock for proton exchange membrane (PEM) electrolysers because trace contaminants can cause failure. Here the authors show that PEM electrolysers can run on impure tap water when Brønsted acid oxides are used at the cathode to create a strongly acidic microenvironment.

Nature Energy, Published online: 09 June 2025; doi:10.1038/s41560-025-01792-y

Dong et al. achieve Sb2(S,Se)3 solar cells with 10.7% efficiency by increasing charge generation with a textured electrode and reducing charge recombination and transport loss with a conformal electron-selective layer.

Energy Environ. Sci., 2025, Accepted Manuscript
DOI: 10.1039/D5EE01454A, PerspectivePengfei Wang, Jiaxing Xu, Zhaoyuan Bai, Ruzhu Wang, Tingxian Li
Water crisis has emerged as one of the most severe threats to global sustainable development. The atmosphere contains approximately 13,000 trillion liters of water as an accessible natural water source...
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Context, Computation, and Continuity: Neural Mechanisms of Memory and Decision-Making

How does the brain achieve both stability and flexibility in behavior? In this journal club, we will explore two recent studies that illuminate distinct yet interconnected neural mechanisms underlying long-term motor memory and flexible decision-making. The first paper (Kim et al., Nature, 2024) demonstrates that motor memories are encoded in a combinatorial, context-specific manner in the motor cortex of mice. Using long-term two-photon imaging, the authors show that new motor skills are acquired without overwriting old ones, as new preparatory activity patterns emerge in parallel across contexts—offering a robust mechanism for continual learning.

The second paper (Pagan et al., Nature, 2024) investigates how individual variability shapes context-dependent decision-making in rats. The authors develop a behavioral paradigm and theoretical framework revealing three distinct dynamical strategies for evidence accumulation, all capable of supporting flexible behavior. Strikingly, different individuals express different combinations of these strategies, despite similar performance, highlighting substantial neural and computational diversity.

Optionally, we will also discuss findings from a third study (Mishchanchuk et al., Science, 2024), which reveals how the ventral hippocampus encodes abstract contextual states critical for hidden state inference. This study complements the others by highlighting the importance of hippocampal representations in decision-making based on latent contexts. Together, these studies provide a compelling picture of how the brain balances flexibility and stability through context-specific encoding, diverse computational strategies, and abstract contextual inference—shedding light on the neural basis of learning, memory, and cognition.

• Speaker: Máté Lengyel; Guillaume Hennequin
• Tuesday 10 June 2025, 11:00-12:30
• Venue: CBL Seminar Room, Engineering Department, 4th floor Baker building.
• Series: Computational Neuroscience; organiser: .

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Context, Computation, and Continuity: Neural Mechanisms of Memory and Decision-Making

How does the brain achieve both stability and flexibility in behavior? In this journal club, we will explore two recent studies that illuminate distinct yet interconnected neural mechanisms underlying long-term motor memory and flexible decision-making. The first paper (Kim et al., Nature, 2024) demonstrates that motor memories are encoded in a combinatorial, context-specific manner in the motor cortex of mice. Using long-term two-photon imaging, the authors show that new motor skills are acquired without overwriting old ones, as new preparatory activity patterns emerge in parallel across contexts—offering a robust mechanism for continual learning. The second paper (Pagan et al., Nature, 2024) investigates how individual variability shapes context-dependent decision-making in rats. The authors develop a behavioral paradigm and theoretical framework revealing three distinct dynamical strategies for evidence accumulation, all capable of supporting flexible behavior. Strikingly, different individuals express different combinations of these strategies, despite similar performance, highlighting substantial neural and computational diversity. Optionally, we will also discuss findings from a third study (Mishchanchuk et al., Science, 2024), which reveals how the ventral hippocampus encodes abstract contextual states critical for hidden state inference. This study complements the others by highlighting the importance of hippocampal representations in decision-making based on latent contexts. Together, these studies provide a compelling picture of how the brain balances flexibility and stability through context-specific encoding, diverse computational strategies, and abstract contextual inference—shedding light on the neural basis of learning, memory, and cognition.

• Speaker: Máté Lengyel; Guillaume Hennequin
• Tuesday 10 June 2025, 11:00-12:30
• Venue: CBL Seminar Room, Engineering Department, 4th floor Baker building.
• Series: Computational Neuroscience; organiser: .

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“Characterizing and preventing host cell entry of emerging RNA viruses”

This Cambridge Immunology Network Seminar will take place on Thursday 12 June 2025, starting at 4:00-5:00pm

Speaker: Professor Thomas Bowden, Wellcome Centre for Human Genetics, Oxford

Title: “Characterizing and preventing host cell entry of emerging RNA viruses”

Host: Yorgo Modis, CITIID , Cambridge

Location: Max Perutz Lecture Theatre, MRC LMB

Refreshments will be available following the seminar.

Please note the change of venue to: Max Perutz Lecture Theatre, MRC LMB

• Speaker: Professor Thomas Bowden, Wellcome Centre for Human Genetics, Oxford
• Thursday 12 June 2025, 16:00-17:00
• Venue: Max Perutz Lecture Theatre, MRC LMB, Francis Crick Avenue, Cambridge CB2 0QH .
• Series: Cambridge Immunology Network Seminar Series; organiser: Ruth Paton.

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Ferroelectric domains, a hallmark of ferroelectricity, are studied using temperature-dependent Raman spectroscopy to uncover characteristic phonons associated with ferroelectric phase transitions in different n-value HOIPs. Higher n-value HOIP demonstrate a reduced ferroelectric switching energy barrier, providing valuable insights for optimizing domain-related properties in ferroelectric devices.

Abstract

Hybrid organic-inorganic perovskites (HOIPs) have emerged as promising ferroelectric semiconductors, yet the phonon signatures governing their ferroelectricity remain poorly understood. Here, by analyzing the temperature-dependent Raman peak profiles of highly ordered ferroelectric domains in HOIPs, a framework to systematically investigate the dimensionality (n)-dependent phonons that are critical to ferroelectric behaviour is established. By tracking phonon evolution across the ferroelectric-to-paraelectric phase transition in HOIPs with different n, characteristic modes associated with the ferroelectric symmetry-breaking process are identified. Notably, in the ferroelectric phase of (BA)2(MA)2Pb3Br10 (n = 3), these modes exhibit a redshift compared to those in (BA)2(MA)Pb2Br7 (n = 2), reflecting a reduced energy barrier for ferroelectric switching. Density functional theory (DFT) calculations further correlate these modes with their spectral signatures in Raman spectroscopy, particularly highlighting zone-boundary modes that diminish upon transitioning to the paraelectric phase. Polarized Raman mapping further reveals adjacent ferroelectric domains with orthogonal polarization orientations, directly linking phonon activity to domain configuration. This work elucidates the role of phonons in HOIP ferroelectricity, offering insights for tailoring domain-related properties in ferroelectric devices.

Thick electrodes promise higher battery energy density but suffer from reaction heterogeneity. While typically attributed to sluggish charge transport, this study shows how thermodynamic properties of active materials also have critical influence. Through advanced X-ray characterization of LiFePO4 and LiNi0.6Mn0.2Co0.2O2 thick electrodes, stark differences in their reaction gradients are revealed and a predictive metric to guide electrode design is introduced.

Abstract

Thick electrodes present a viable strategy for enhancing energy density and reducing manufacturing costs of lithium-ion batteries. However, reaction heterogeneity during cycling compromises their rate capability and cycle life. While this nonuniformity is commonly attributed to sluggish charge transport, it is demonstrated here that the thermodynamic properties of the electrode material play an equally critical role. Through combined X-ray fluorescence microscopy and absorption near-edge structure spectroscopy, reaction distributions in LiFePO4 (LFP) and LiNi0.6Mn0.2Co0.2O2 (NMC) thick electrodes with matched porosity and tortuosity are compared. LFP electrodes develop pronounced depth-oriented state-of-charge (SOC) gradients that worsen with increasing discharge rates, whereas NMC maintains much more uniform SOC distributions under such conditions. This difference originates from their distinct SOC dependence of equilibrium potentials and is quantifiable through a dimensionless “reaction uniformity” number. Intriguingly, LFP thick electrodes also exhibit lateral SOC variations that strengthen during slow discharge. The enhanced reaction uniformity in NMC correlates with better active material utilization and slower capacity fade than LFP, highlighting electrode thermodynamics as a key design consideration for thick electrodes.

The fabrication of micro- and macro-scale 3D-printed multi-material structures incorporating photocatalytically active Ru(II) sites using a dual-function photoresin is introduced. The system utilizes a Ru(II)-functionalized monomer, enabling the assembly of 3D structures with commercially available crosslinkers. The catalytic activity is demonstrated through the C─H arylation of activated aryl bromides.

Abstract

Light-induced additive manufacturing (3D printing) has revolutionized manufacturing and its integration into the fabrication of catalysts holds key potential to enable facile access to optimized catalyst geometries and designs. Herein – for the first time – micro- and macro-sized photocatalytically active 3D printed objects are introduced via a dual-function photoresin using a ruthenium(II) complex containing monomer as both a photoinitiator for the 3D printing process and as the active photocatalyst within the printed structure. The approach leverages the spatial and temporal control afforded by light-induced 3D printing techniques during both one- and two-photon printing to precisely position the photocatalyst within intricate geometries using a pentaerythritol triacrylate (PETA) based resin. The successful incorporation of ruthenium(II) complexes is demonstrated via time-of-flight secondary-ion mass spectrometry (ToF-SIMS) into desired sections of 3D-printed objects. The one- and two-photon fabricated architectures show photocatalytic activity in the C─H arylation of activated aryl bromides. The potential of tailored catalytically active 3D objects is exemplified by one of the microscale designs. This design, utilizing only 1% of the volume of a macroscale structure fabricated from the same resin, achieved 75% of the photocatalytic performance.

Inspired by clouds' role in Earth's thermal management, this work presents disordered plasmonic metasurfaces that mimic their radiative effects. The white metasurface enhances backscattering, acting as a cooling layer with camouflage properties. The grey state suppresses backscattering and enhances light trapping, surpassing conventional black absorbers. These metasurfaces enable advancements in camouflage, low-emissivity coatings, and thermal infrared stealth technologies.

Abstract

Inspired by nature's color-driven thermal regulation mechanisms and the atmospheric radiative effects of cloud-aerosol interactions, this work presents the design of disordered metasurfaces capable of achieving white and grey plasmonic colors. This innovation advances light and thermal management technologies within the framework of stealth and camouflage applications. The white plasmonic metasurfaces emulate the cooling effects of clouds, reducing substrate temperatures by a relative −10 °C under standard solar illumination through backscattering. In contrast, transitioning to a grey state with a nanocomposite absorber suppresses backscattering and enables efficient light trapping, resulting in a relative +10  °C temperature increase compared to conventional black absorbers. These findings introduce a novel approach to localized thermal management, distinct from traditional passive cooling strategies that rely on high-emissivity materials. The metasurfaces’ low-emissivity properties and visible appearance open opportunities in advanced camouflage, stealth technologies, and thermal energy solutions. Additionally, the scalable, sustainable design, realized through all-in-chamber nanofabrication via sputtering, eliminates the need for chemically intensive synthesis methods while ensuring long-term stability.

We demonstrate dynamic control of ferroelectric order in quasi-2D CsBiNb2O7 using twisted ultraviolet light carrying orbital angular momentum. Our approach harnesses non-resonant multiphoton absorption and induced strain to modulate topological of ferroelectric polarization textures. In-situ X-ray coherent imaging and Raman spectroscopy reveal reversible, nanoscale polarization transitions, enabling efficient stabilization of topological solitons and paving the way for novel optoelectronic devices.

Abstract

The dynamic control of non-equilibrium states represents a central challenge in condensed matter physics. While intense terahertz fields drive metal-insulator transitions and ferroelectricity via soft phonon modes, recent theory suggests that twisted light with orbital angular momentum (OAM) offers a distinct route to manipulate ferroelectric order and stabilize topological excitations including skyrmions, vortices, and Hopfions. Control of ferroelectric polarization in quasi-2D CsBiNb2O7 (CBNO) is demonstrated using non-resonant twisted ultra-violet (UV) light (375 nm, 800 THz). Combining in situ X-ray Bragg coherent diffractive imaging (BCDI), twisted optical Raman spectroscopy, and density functional theory (DFT), three-dimensional (3D) ionic displacements, strain fields, and polarization changes are resolved in single crystals. Operando measurements reveal light-induced strain hysteresis under twisted light–a hallmark of nonlinear, history-dependent ferroelastic switching driven by OAM. Discrete, irreversible domain transitions emerge as the topological charge ℓ is cycled, stabilizing non-trivial domain textures including vortex-antivortex pairs, Bloch/anti-Bloch points, and merons. These persist after OAM removal, indicating a memory effect. Competing mechanisms are discussed, including multiphoton absorption, strain-mediated polarization switching, and defect-wall interactions. The findings establish structured light as a tool for deterministic, reversible control of ferroic states, enabling optically reconfigurable non-volatile devices.

Probabilistically Robust Decision Making for Uncertain Dynamical Systems

Typically, how much do we know about an uncertain dynamical system (UDS) matters a lot when we want to control them. Aiming to accurately capture the evolution of such UDS is impossible as true system uncertainties cannot be captured exactly. Lack of exact system knowledge increases the difficulty in estimating the limits of the uncertain system’s performance. As a result, we often seek to control such UDS such that the resulting control decisions from Robust Decision Making (RDM) paradigms render the UDS insensitive to what we don’t know about them. However, nature can violate the assumptions that the RDM module assume for the system uncertainties with small probability. Controlling UDS under such unforeseen events necessitate the addition of probabilistic rigour on top of the existing RDM approaches. In this talk, I shall propose a Probabilistic RDM (PRDM) approach using the uncertain gap between the dynamical system models (with and without the uncertainty) induced by appropriate distance metric. The proposed framework will allow us to analyse the potential performance degradation of a control action on an UDS when such rare violation events occur. The fertile nature of the probabilistic robust control research area will be highlighted using a list of interesting future research directions.

The seminar will be held in JDB Seminar Room, Department of Engineering, and online (zoom): https://newnham.zoom.us/j/92544958528?pwd=YS9PcGRnbXBOcStBdStNb3E0SHN1UT09

• Speaker: Venkatraman Renganathan, Cranfield University
• Thursday 12 June 2025, 14:00-15:00
• Venue: JDB Seminar Room, Department of Engineering and online (Zoom).
• Series: CUED Control Group Seminars; organiser: Fulvio Forni.

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Energy Environ. Sci., 2025, Advance Article
DOI: 10.1039/D5EE01894C, PaperKang Xu, Yangsen Xu, Feng Zhu, Zhiwei Du, Xirui Zhang, Zhuo Cheng, Yu Chen
A cost-effective interfacial engineering strategy is proposed to improve the performance of reversible protonic ceramic electrochemical cells by incorporating the design of active electrodes and the construction of nanostructured interlayers.
To cite this article before page numbers are assigned, use the DOI form of citation above.
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Title to be confirmed

Abstract not available

• Speaker: Allan McRobie, University of Cambridge
• Friday 13 June 2025, 15:00-16:00
• Venue: CivEng Seminar Room (1-33) (Civil Engineering Building).
• Series: Engineering Department Structures Research Seminars; organiser: Shehara Perera.

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Latent Concepts in Large Language Models

Large Language Models (LLMs) have achieved remarkable fluency and versatility—but understanding how they represent meaning internally remains a challenge. In this talk, we explore the emerging science of latent concepts in LLMs: the semantic abstractions implicitly encoded in their internal activations.

We examine how concepts—such as truthfulness, formality, or sentiment—can be represented as low-dimensional structures, discovered through training dynamics, and understood through the lens of linear algebra and associative memory. We discuss the implications for interpretability, robustness, and control, including how concepts can be steered at test time to adjust model behavior without retraining. Specifically, we explore empirical and theoretical evidence supporting the linear representation hypothesis, where such concepts correspond to vectors or affine subspaces, emerging naturally from training dynamics and next-token prediction objectives. We further show that LLMs behave as associative memory systems, retrieving outputs based on latent similarity rather than logical inference. This behavior underlies phenomena such as context hijacking, where semantically misleading prompts can bias the model’s response.

We introduce formal latent concept models that unify these ideas, describe conditions under which concepts are identifiable, and propose learning algorithms for extracting interpretable, controllable representations. We argue that such latent concept modeling offers a principled framework for bridging representation learning with interpretability and model alignment, and offers a promising path toward safer, more controllable, and more trustworthy AI.

• Speaker: Prof. Pradeep Ravikumar, Carnegie Mellon University
• Tuesday 10 June 2025, 14:00-15:00
• Venue: JDB Seminar Room, CUED.
• Series: Probabilistic Systems, Information, and Inference Group Seminars; organiser: Prof. Ramji Venkataramanan.

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Energy Environ. Sci., 2025, Accepted Manuscript
DOI: 10.1039/D5EE00877H, Paper Open Access &nbsp This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.Wei Zhang, Liang He, Jiantao Li, Ruohan Yu, Zhenming Xu, Yulun Wu, Haotian Qu, Qi Zhang, Jianwei Li, Xian Wu, Qingjin Fu, Yanqing Lai, Guangmin Zhou, Guanjie He, Ivan P. Parkin
Sodium-ion batteries (SIBs) are a promising solution for large-scale energy storage, but their development is hindered by the limited performance of cathode materials. NASICON (Na Superionic Conductor)-type compounds offer fast...
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Title to be confirmed

Abstract not available

• Speaker: Max Ryabinin
• Wednesday 18 June 2025, 15:00-16:00
• Venue: Computer Lab, LT1.
• Series: Cambridge ML Systems Seminar Series; organiser: Sally Matthews.

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Mixing and chemical transfers in particle clouds – implications following planetary impacts

At a late stage of its accretion, the Earth experienced high-energy planetary impacts. Following each collision, the metal core of the impactor sank as millimetric drops into a molten silicate magma ocean. The efficiency of chemical equilibration between these silicates and the metal core controlled the composition of the Earth controlled the initial temperature and composition of rocky planets, and hence the emergence of plate tectonics, the time when a solid inner core started to grow, or the driving of an early dynamo in the Earth’s core by exsolution of light elements.

In this talk I will present different experiments focusing on the interaction of settling particle clouds with their surrounding through entrainment, mixing and chemical reactions. I will first present experiments on inert clouds settling in a quiescent fluid. Then, I will discuss the implications of planetary rotation on the efficiency of chemical transfers inside particle clouds, largely disregarded despite the strong rotation rate of the proto-Earth that has been suggested by impact simulations.

• Speaker: Quentin Kriaa, Uni of Cambridge
• Thursday 12 June 2025, 11:30-12:30
• Venue: Open Plan Area, Institute for Energy and Environmental Flows, Madingley Rise CB3 0EZ.
• Series: Institute for Energy and Environmental Flows (IEEF); organiser: Catherine Pearson.

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