Nanoscience News (<front>)

A time-division multiplexing physical unclonable function (TDM-PUF) label based on multicolor phosphorescent carbon dots (CDs) is proposed, which leverages the variations in wavelengths and lifetimes of the phosphorescent CDs to construct time-resolved multidimensional cryptographic protocols. This study provides a competitive anti-counterfeiting label and inspires the development of novel anti-counterfeiting strategies.

Abstract

Phosphorescent materials offer a promising approach to information encryption due to their long luminescence lifetimes and high signal-to-noise ratios. However, fixed phosphorescent patterns are vulnerable to imitation over time, limiting their effectiveness in advanced encryption. Here, a time-division multiplexing physical unclonable function (TDM-PUF) label utilizing multicolor phosphorescent carbon dots (CDs) is proposed that leverages variations in wavelength and lifetime to construct time-resolved, multidimensional cryptographic protocols. Efficient multi-color phosphorescence in CDs is achieved by enhancing intersystem crossing, suppressing non-radiative transitions through confinement effects, and regulating emission spectra via energy transfer. The random spatial distribution and unpredictable emissions of phosphorescent CDs significantly enhance the complexity of the PUF system, thereby fortifying its defenses against mimicry attacks. Furthermore, this PUF system exhibits multiple optical responses over time, allowing correct information recognition only at specified time nodes, achieving time-resolved anti-counterfeiting. Finally, by segmenting PUF labels based on emission color and time channels, non-overlapping multicolor and multi-time segments are achieved, enabling highly secure time-division multiplexed encryption. The study provides a competitive anti-counterfeiting label and inspires the development of novel anti-counterfeiting strategies.

Understanding the complex interplay between local structure and physical properties is a key challenge in high entropy oxide (HEO) research, particularly concerning electronic transport. This work demonstrates the profound influence of local chemical inhomogeneity and underlying epitaxial strain on the electronic transport properties of HEO thin film with perovskite structure, paving pathways to tailor electronic properties in high-entropy regime.

Abstract

Understanding the electronic transport properties of thin films of high-entropy oxide (HEO), having multiple elements at the same crystallographic site, is crucial for their potential electronic applications. However, very little is known about the metallic phase of HEOs even in bulk form. This work delves into the interplay between global and local structural distortion and electronic properties of single crystalline thin films of (La0.2Pr0.2Nd0.2Sm0.2Eu0.2)NiO3, which exhibit metal-insulator transition under tensile strain. Employing electron microscopy and elemental resolved electron energy loss spectroscopy, we provide direct evidence of nanoscale chemical inhomogeneities at the rare-earth site, leading to a broad distribution of Ni–O–Ni bond angles. However, the octahedral rotation pattern remains the same throughout. The metallic phase consists of insulating patches with more distorted Ni–O–Ni bond angles, responsible for higher resistance exponents with increased compositional complexity. Moreover, a rare, fully metallic state of HEO thin film is achieved under compressive strain. We further demonstrate a direct correlation between the suppression of the insulating behavior and increased electronic hopping. Our findings provide a foundation for exploring Mott-Anderson electron localization physics in the high-entropy regime.

A core-shell perovskite composite with a highly durable electrochemical activity for oxygen catalysis is developed as an air electrode for reversible protonic ceramic cells (RPCCs) via a unique solid-state reaction. This work also demonstrates a new pathway to developing highly durable air electrode materials for RPCCs technology, accelerating RPCCs’ commercialization.

Abstract

Reversible protonic ceramic cells (RPCCs) offer a promising pathway to efficient and reversible energy conversion, accelerating the global shift to renewables. However, the RPCCs’ commercialization faces limitations in air electrode materials. Traditional cobalt-based perovskite air electrodes, while effective, suffer from high cost and environmental concerns. Alternative materials, such as SrFeO3-δ (SF)-based perovskites, offer potential, yet durability issues, including thermal-expansion mismatch and mechanical instability, hinder their practical application. Here, a unique solid-state reaction between SF and negative-thermal-expansion (NTE) material is demonstrated to yield a core-shell perovskite composite as a highly durable RPCCs air electrode. Specifically, by calcining a mixture of SF and an NTE material, ZrW2O8 (ZWO), the in situ incorporation of ZWO into the SF lattice is achieved, resulting in a non-closed core-shell composite, comprising single perovskite SraFebZrcWdO3-δ (SP-SFZW) core and B-site cation ordered double perovskite SrxFeyZrmWnO6-δ (DP-SFZW) shell. Both SP-SFZW and DP-SFZW serve as oxygen catalysts, while DP-SFZW shell additionally acts as a thermal expansion suppressor and mechanical support structure, effectively mitigating electrode cracking and delamination from other cell components during RPCC operation. Consequently, the composite electrode demonstrates comparable catalytic activity to SF, coupled with significantly enhanced durability. This work illustrates a novel approach for developing robust RPCCs air electrode.

An AEM-derived proton acceptor-electron donor mechanism is proposed in RuO2 by constructing an interstitial-substitutional mixed solid solution structure (C,Ta-RuO2), in which the interstitial C as the proton acceptor decreases the deprotonation energy barrier, while the substitutional Ta as the electron donor weakens the Ru─O bond covalency, thereby breaking the activity-stability trade-off of RuO2 in acidic OER.

Abstract

The acidic oxygen evolution reaction (OER) electrocatalysts for proton exchange membrane electrolyzer (PEMWE) often face a trade-off between activity and stability due to inherent linear relationship and overoxidation of metal atoms in highly oxidative environments, while following the conventional adsorbate evolution mechanism (AEM). Herein, a favorable AEM-derived proton acceptor-electron donor mechanism (PAEDM) is proposed in RuO2 by constructing interstitial-substitutional mixed solid solution structure (denoted as C,Ta-RuO2), which can effectively break the activity-stability trade-off of RuO2 in acidic OER. In situ spectroscopy experiments and theoretical calculations reveal that the interstitial C as the proton acceptor reduces the deprotonation energy barrier, enhancing catalytic activity, while the substitutional Ta as the electron donor donates electrons to the Ru sites via bridging oxygen, weakening the Ru─O bond covalency and preventing over-oxidation of surface Ru, thereby ensuring long-term stability. Under the guidance of this mechanism, the optimized C,Ta-RuO2 simultaneously achieves far low overpotential (η10 = 171 mV) and ultra-long stability (over 1300 h) for the acidic OER. More remarkably, a homemade PEMWE using C,Ta-RuO2 as the anode also shows high water splitting performance (1.63 V@1 A cm−2). This work supplies a novel strategy to guide future developments on efficient OER electrocatalysts toward water oxidation.

Breaking Quantum Confinement in Yb3⁺-Doped ZnSe QDs: Surface-energy engineering enables scalable growth beyond the exciton Bohr radius with high-purity blue emission (453 nm), narrow full width at half maximum (FWHM) of 46 nm, and exceptional photoluminescence quantum yield (PLQY) of 67.5%.

Abstract

Large ZnSe quantum dots (QDs) with an emission peak ≈450 nm hold significant promise for display technologies. However, achieving efficient pure-blue emission through the enlargement of ZnSe nanocrystals remains a significant challenge. In this study, a breakthrough is reported in growing large-size ZnSe QDs well beyond the exciton Bohr radius through Yb3+ doping strategy. Yb3+ doping reduces the surface energy of the ZnSe (220) crystal plane and alleviates interface strain in the ZnSe/ZnS structure, enabling the QDs to grow larger while maintaining enhanced crystal stability. The resulting Yb: ZnSe/ZnS QDs exhibit pure-blue emission at 453 nm, with a full width at half maximum (FWHM) of 46 nm and a high photoluminescence quantum yield (PLQY) of 67.5%. When integrated into quantum dot light-emitting diodes (QLEDs), the devices display electroluminescence (EL) at 455 nm, with an external quantum efficiency (EQE) of 1.35%, and a maximum luminance of 1337.08 cd m−2.

A heterogeneous microgel–hydrogel hybrid is developed to construct a multiscale vascular network through embedded bioprinting and guided vascular morphogenesis. With a high density of hepatocytes, a bioengineered thick vascularized liver tissue model achieves a rapid and promising functional compensation in rats with 85% hepatectomy via direct vascular integration, providing a theraputi paradigm for physiological-related engineered tissue in animals with acute disease.

Abstract

3D bioprinting of liver tissue with high cell density (HCD) shows great promise for restoring function in cases of acute liver failure, where a substantial number of functional cells are required to perform essential physiological tasks. Direct vascular anastomosis is critical for the successful implantation of these bioprinted vascularized tissues into the host vasculature, allowing for rapid functional compensation and addressing various acute conditions. However, conventional hydrogels used to encapsulate high-density cells often lack the mechanical properties needed to withstand the shear forces of physiological blood flow, often resulting in implantation failure. In this study, a heterogeneous microgel–hydrogel hybrid is developed to carry HCD hepatocytes and support the embedded bioprinting of hierarchical vascular structures. By optimizing the ratio of microgel to biomacromolecule, the covalently crosslinked network offers mechanical integrity and enables direct vascular anastomosis, ensuring efficient nutrient and oxygen exchange. The bioprinted thick, vascularized constructs, containing HCD hepatocytes, are successfully implanted in rats after 85% hepatectomy, leading to swift functional recovery and prolonged survival. This study presents a strategy to enhance regenerative therapy outcomes through advanced bioprinting and vascular integration techniques.

The α-FAPbI3 perovskite, ideal for high-efficiency solar cells, suffers from impurity phases causing defects and instability. Using FAI/MASCN vapors repairs impurities into α-FAPbI3, enhancing charge transport and morphology. This achieves 26.05% efficiency, with large-area devices (24.52% for 1 cm2, 22.35% for 17.1 cm2). Cyclic repair retains 94.3% efficiency after two cycles, significantly boosting device durability.

Abstract

The photoactive α-phase of formamidinium lead iodide perovskite (α-FAPbI3) is regarded as one of the ideal materials for high-efficiency perovskite solar cells (PSCs) due to its superior optoelectronic properties. However, during the deposition of α-FAPbI3 perovskite films, the presence of impurity phases, such as PbI2 and δ-FAPbI3, can cause the formation of inherent defects, which leads to suboptimal charge transport and extraction properties, as well as inadequate long-term stability in the film's morphology and structure. To address these issues, an impurity phase repair strategy is employed using FAI/MASCN mixed vapors to convert the impurity phases into light-absorbing α-FAPbI3. Meanwhile, this recrystallization process also facilitates the recovery of its characteristic morphology, thereby improving efficiency and enhancing the durability of PSCs. This approach promotes the PSCs to obtain an efficiency of 26.05% (with a certified efficiency of 25.67%, and steady-state PCE of 25.41%). Additionally, this approach is suitable for the fabrication of large-area devices, obtaining a 1 cm2 device with a PCE of 24.52% and a mini-module (with an area of 17.1 cm2) with a PCE of 22.35%. Furthermore, it is found that this strategy enables cyclic repair of aged perovskite films, with the perovskite solar cells retaining ≈ 94.3% of their initial efficiency after two cycles of repair, significantly enhancing the lifetime of the perovskite solar cells.

A self-assembled interface orthogonal strategy is first applied to construct pseudo-planar heterojunction organic photovoltaics with controllable vertical gradient distribution morphology. Introducing low surface-energy N2200 to self-assemble molecular layer on PM6 surface overcomes erosion effect and modulates phase morphology, thus achieving the highest efficiency of 19.86% via air-printing process.

Abstract

Precisely regulating vertically distributed morphology by blade-coating process is crucial to realize high-performance large-scale pseudo-planar heterojunction organic photovoltaics (OPVs). However, the thermodynamic motion and random diffusion of donor/acceptor (D/A) generated from the differences in surface energy and concentration during sequentially blade-coating process will cause great challenges for obtaining ideal active layer morphology. Herein, this study have proposed a self-assembled interface orthogonal strategy by introducing low surface energy guest (N2200) to form protective layer on PM6 surface, which counteracts erosion from orthogonal solution of acceptor to enhance continuity of D/A phases, thus promoting directional carrier migration and effectively suppressing energetic disorder. Finally, N2200-modified device achieves the highest power conversion efficiency (PCE) of 19.86%, and large-area module (16.94 cm2) exhibits exceptional PCE (16.43%). This investigation presents innovative insights into morphology issue triggered by molecular motion and provides an effective method for air-printing large-scale OPVs with precisely controlled morphology based on non-halogenated solvent.

A novel copper-sulfur-nitrogen cluster Cu8SN is synthesized by using a strong anchoring ability protective ligand (2-mercaptopyrimidine) and a relatively weak monodentate tert-butyl mercaptan ligand. Then, a precise thermal-resection strategy is applied to only peel the targeted weak ligands off, which induces a structural transformation of the initial Cu8SN cluster into a new and more stable Cu–S–N cluster (Cu8SN–T). Cu8SN–T exhibits greatly enhanced light-harvesting abilities and full-spectrum responsive overall CO2 photoreduction with ≈100% CO2-to-CO selectivity.

Abstract

Atomically precise copper clusters are desirable as catalysts for elaborating the structure–activity relationships. The challenge, however, lies in their tendency to sinter when protective ligands are removed, resulting in the destruction of the structural integrity of the model system. Herein, a copper-sulfur-nitrogen cluster [Cu8(StBu)4(PymS)4] (denoted as Cu8SN) is synthesized by using a mixed ligand approach with strong chelating 2-mercaptopyrimidine (PymSH) ligands and relatively weak monodentate tert-butyl mercaptan ligands. A precise thermal-resection strategy is applied to selectively peel only the targeted weak ligands off, which induces a structural transformation of the initial Cu8 cluster into a new and more stable Cu–S–N cluster [Cu8(S)2(PymS)4] (denoted as Cu8SN-T). The residual bridging S2− within the metal core forms asymmetric Cu-S species with a near-infrared (NIR) response, which endows Cu8SN-T with the capability for full-spectrum responsive CO2 photoreduction, achieving a ≈100% CO2-to-CO selectivity. Especially for NIR-driven CO2 reduction, it has a CO evolution of 42.5 µmol g−1 under λ > 780 nm. Importantly, this work represents the first NIR light-responsive copper cluster for efficient CO2 photoreduction and opens an avenue for the precise manipulation of metal cluster structures via a novel thermolysis strategy to develop unprecedented functionalized metal cluster materials.

Completeness Theorems for Variations of Higher-Order Logic

Mike Gordon’s Higher-Order Logic (HOL) is one of the most important logical foundations for interactive theorem proving. The standard semantics of HOL , due to Andrew Pitts, employs a downward closed universe of sets, and interprets HOL ’s Hilbert choice operator via a global choice function on the universe.

In this talk, I introduce a natural Henkin-style notion of general model corresponding to the standard models. By following the Henkin route of proving completeness, I discover an enrichment of HOL deduction that is sound and complete w.r.t. these general models. Variations of my proof also yield completeness results for weaker deduction systems located between standard and (fully) enriched HOL deduction, relative to less constrained models.

=== Hybrid talk ===

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

Meeting ID: 871 4336 5195

Passcode: 541180

• Speaker: Andrei Popescu (University of Sheffield)
• Thursday 15 May 2025, 17:00-18:00
• Venue: MR14 Centre for Mathematical Sciences.
• Series: Formalisation of mathematics with interactive theorem provers ; organiser: Anand Rao Tadipatri.

Add to your calendar or Include in your list

In-Context Learning

TBC

• Speaker: Yashar Ahmadian; Nandini Shiralkar
• Tuesday 15 April 2025, 15:00-16:30
• Venue: CBL Seminar Room, Engineering Department, 4th floor Baker building.
• Series: Computational Neuroscience; organiser: .

Add to your calendar or Include in your list

bla bla

bla bla

• Speaker: Lukas pertl
• Monday 12 May 2025, 17:00-17:45
• Venue: Lecture Theatre 2, Computer Laboratory, William Gates Building.
• Series: Foundation AI; organiser: Pietro Lio.

Add to your calendar or Include in your list

Title to be confirmed

Abstract not available

• Speaker: Rajalakshmi Nandakumar, Cornell University
• Tuesday 03 June 2025, 16:00-17:00
• Venue: Online.
• Series: Mobile and Wearable Health Seminar Series; organiser: Cecilia Mascolo.

Add to your calendar or Include in your list

Title to be confirmed

Abstract not available

• Speaker: Paul Röttger (Bocconi University)
• Friday 16 May 2025, 12:00-13:00
• Venue: Room FW26 with Hybrid Format. Here is the Zoom link for those that wish to join online: https://cam-ac-uk.zoom.us/j/4751389294?pwd=Z2ZOSDk0eG1wZldVWG1GVVhrTzFIZz09.
• Series: NLIP Seminar Series; organiser: Suchir Salhan.

Add to your calendar or Include in your list

The Case for Decentralized Scheduling in Modern Datacenters

Join on MS Teams

The growing demand for data centre resources and the slower evolution of their hardware have led to clusters operating at high utilisation. In this talk, I will examine how current schedulers perform under such conditions. I will discuss how centralised schedulers struggle to scale under high load due to the significant network traffic caused by continuously transferring up-to-date node data. Conversely, distributed schedulers scale well but lack a global cluster view, leading to suboptimal task allocations. As a result, existing schedulers impose up to three times longer wait times on tail tasks, which increases job completion times.

I will then introduce our work on decentralised scheduling, focusing on performance, scalability, and load balancing. These schedulers have been largely under-explored due to their design complexity. However, we demonstrate that Murmuration, our job-aware decentralised scheduler, achieves high performance under both normal and high load despite its simple approach using approximate load information. It reduces communication overhead between nodes and schedulers while still achieving balanced cluster load distribution. By the end of this talk, I hope to convince you that decentralised schedulers with approximate knowledge strike the right balance between performance and scalability, making them a practical solution for today’s highly utilised data centres.

Bio: Smita Vijayakumar recently completed her PhD from the Department of Computer Science and Technology at the University of Cambridge, under the supervision of Evangelia Kalyvianaki. As a part of her thesis, she developed a novel decentralised scheduling framework to reduce tail task latencies in highly utilised data centres. She has over twelve years of industry experience working on networking, cloud computing, and distributed systems. She also has an MS from The Ohio State University, where her work investigated cloud resource allocation to bottleneck stages for processing streaming applications. Her research has been published in top-tier conferences, and also as a book. She has also been actively involved in mentoring, teaching, and community leadership, including founding Women Who Go, India.

• Speaker: Smita Vijayakumar, Systems Research Group, Cambridge University Computer Laboratory
• Thursday 01 May 2025, 15:00-16:00
• Venue: Computer Lab, FW11 and Online (MS Teams link below).
• Series: Computer Laboratory Systems Research Group Seminar; organiser: Richard Mortier.

Add to your calendar or Include in your list

A chlorine-substituted aromatic polycyclic compound is introduced into perovskite solar cells to regulate perovskite crystallization, passivate various defects, and enhance hole transport at the HTL/perovskite interface. This approach achieved high efficiencies of 25.04% for 1 cm2 cells and 22.81% for 12 cm2 modules, with excellent stability (maintaining 80% of initial efficiency after 2500 h of MPP tracking under ISOS-L-1 standards).

Abstract

Film morphology and surface/interface defect density play a critical role in determining the efficiency and stability of perovskite solar cells (PSCs). Here, a chlorine-substituted aromatic polycyclic derivative (BNCl) is reported, which shows strong interaction with both lead iodide and dimethyl sulfoxide, to regulate the crystallization of perovskite, along with effective passivation of grain boundaries and surface. In addition, the extruded BNCl molecule at the hole transport layer (HTL)/perovskite interface can facilitate the hole transport, leading to better charge transfer. As a result, certified power conversion efficiencies (PCEs) of 25.04% and 22.81% are achieved for PSCs and minimodules with aperture areas of 1 cm2 and 12 cm2 respectively. In addition, the device maintained 80% of its initial efficiency after 2500 h of maximum power point (MPP) tracking under ISOS-L-1 standard.

Energy Environ. Sci., 2025, Accepted Manuscript
DOI: 10.1039/D5EE01058F, CommunicationFan Bu, Shaofei La, Wenbo Zhao, Yifan Deng, Yong Gao, Jizhang Jiang, Qinghe Cao, Jipeng Chen, Pei Song Chee, Salah A. Makhlouf, Cao Guan
Zn-based batteries have been considered as promising alternatives for Li-ion batteries, in terms of high safety, low cost and rich natural resources. Unfortunately, their practical application is greatly limited by...
The content of this RSS Feed (c) The Royal Society of Chemistry

Energy Environ. Sci., 2025, Accepted Manuscript
DOI: 10.1039/D5EE00812C, PaperChangjing Xu, Jie Yang, Sergio Gámez-Valenzuela, Jin-Woo Lee, Jiaxu Che, Peng Chen, Guodong Zhang, Hu Dingqin, Yufei Wang, Jichen Lv, Zhicheng Zhong, Xihan Chen, Guangye Zhang, Fuwen Zhao, Bumjoon Kim, Xugang Guo, Bin Liu
Ternary organic solar cells (TOSCs) based on dual polymer donors offer enhanced absorption and stability by broadening spectral coverage and refining phase morphology. However, the inherent chain entanglement of dual...
The content of this RSS Feed (c) The Royal Society of Chemistry

Bioelectronic Medicine

Neurological conditions affect one in six people, imposing significant health, economic and societal burden. Bioelectronic medicine aims to restore or replace neurological function with the help of implantable electronic devices. Unfortunately, significant technological limitations prohibit these devices from reaching patients at scale, as implants are bulky, require invasive implantation procedures, elicit a pronounced foreign body response, and show poor treatment specificity and off-target effects. Over the past decade, novel materials and fabrication methods inspired from the microelectronics industry have been shown to overcome these limitations. Recent literature provides powerful demonstrations of thin film implants that are miniaturised, ultra-conformal, stretchable, multiplexed, integrated with different sensors and actuators, bioresorbable, and minimally invasive. This talk discuss the state-of-the-art of these new technologies and the barriers than need to be overcome to reach patients at scale.

More details here.

• Speaker: Professor George Malliaras FRS, Prince Philip Professor of Technology, Department of Engineering, Cambridge University
• Monday 12 May 2025, 19:30-21:00
• Venue: Location: Wolfson Lecture Theatre, Churchill College, and Zoom.
• Series: Cambridge Society for the Application of Research (CSAR); organiser: John Cook.

Add to your calendar or Include in your list

An Introduction to The Alan Turing Institute, the National Institute for Data Science, and Artificial Intelligence

The Alan Turing Institute was established ten years ago and, in this time, it has delivered a number of worlds firsts such as the first 3D printed stainless steel pedestrian bridge, a digital twin of the United Kingdom’s air space, digital twins of cardiac systems in patients, as well as the research vessel the Sir David Attenborough. This talk will focus on some of the achievements of the institute and describe the Grand Challenges it has defined to address contemporary societal issues we face globally namely in the Environment and Sustainability, Defence and Security, and Health and Medicine.

More details here.

• Speaker: Professor Mark Girolami, Chief Scientist, The Alan Turing Institute; RAE Research Chair in Data Centric Engineering, Cambridge University Engineering Department
• Monday 16 June 2025, 19:30-21:00
• Venue: Location: Wolfson Lecture Theatre, Churchill College, and Zoom.
• Series: Cambridge Society for the Application of Research (CSAR); organiser: John Cook.

Add to your calendar or Include in your list