Thu 08 May 14:00: Title to be confirmed
Abstract not available
- Speaker: Prof. Nikos Nikiforakis (Cambridge)
- Thursday 08 May 2025, 14:00-15:30
- Venue: Seminar Room 2, RDC.
- Series: Theory of Condensed Matter; organiser: Bo Peng.
Deciphering the Interplay between Tin Vacancies and Free Carriers in the Ion Transport of Tin-Based Perovskites
DOI: 10.1039/D5EE00632E, Paper Open Access   This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.Luis Huerta Hernandez, Luis Lanzetta, Anna M. Kotowska, Ilhan Yavuz, Nikhil Kalasariya, Badri Vishal, Martí Gibert-Roca, Matthew Piggott, David J Scurr, Stefaan De Wolf, Martin Stolterfoht, Derya Baran
Mixed ionic-electronic conduction is a prevalent phenomenon in metal halide perovskites, having a critical impact in multiple optoelectronic applications. In Sn-based halide perovskites, their higher hole density ([p]) owing to...
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Porous Single‐Crystalline Molybdenum Nitride Monoliths at the Centimeter Scale Surpass Platinum for all pH Hydrogen Evolution
Centimeter-sized porous single-crystalline MoN monoliths with unsaturated Mo–N coordination structures are fabricated through solid-state phase transformation. The porous single-crystalline MoN integrates the structural features, suitable hydrogen adsorption energy, high electronic conductivity and intrinsic catalytic activity, demonstrating low Tafel slopes, minimal charge transfer resistances and long-term stability across all-pH conditions, significantly surpassing traditional Pt/C electrodes.
Abstract
Platinum is widely used in the important components in most electrochemical energy conversion systems while as a noble metal it faces the inevitable challenge of limited reserves. Herein, porous single–crystalline (PSC) molybdenum nitride (MoN) monoliths are reported at the centimeter scale that surpass platinum for all–pH hydrogen evolution. Free–standing PSC MoN electrode with the pore size of ≈6 nm and porosity of ≈72% present both noble–metal–like electronic structure and unsaturated Mo─N coordination structures at surface, contributing to remarkably high intrinsic electrocatalytic activity. The unprecedented overpotentials of as low as 13 and 11 mV are presented at the geometrical current density of 10 mA cm−2 for hydrogen evolution in H2SO4 (pH 0) and KOH (pH 14) media, respectively, which is dramatically superior to commercial Pt electrodes. As a result of the structural stability, the outstanding long–term durability for all pH hydrogen evolution is demonstrated without visible degradation in a continuous operation for 300 h.
Micro‐ and Nano‐Bots for Infection Control
This review presents a strategic vision for integrating micro- and nanobots in the pipeline for infection diagnosis, prevention, and treatment. To develop these robots as a practical solution for infection management, their design principles are clarified based on their propulsion mechanisms and then categorized infection management domains based on usage scenarios.
Abstract
Medical micro- and nano-bots (MMBs and MNBs) have attracted a lot of attention owing to their precise motion for accessing difficult-to-reach areas in the body. These emerging tools offer the promise of non-invasive diagnostics and therapeutics for a wide range of ailments. Here, it is highlighted how MMBs and MNBs can revolutionize infection management. The latest applications of MMBs and MNBs are explored for infection prevention, including their use as accurate, minimally invasive surgeons and diagnosis, where they function as sensitive and rapid biosensors or carriers for contrast agents for real-time imaging of infected tissue. Further, the applications are outlined in treatment serving as anti-biofilm agents and smart carriers for antibiotics and anti-infective biologics. The current challenges in designing MMBs and MNBs are highlighted for overcoming immune barriers, moving to deep infected tissue, and swimming in low Reynolds numbers and discuss mitigating strategies. Finally, as a future perspective, the potential advantages of multi-drive propulsion, bioinspired, and artificial-intelligence-trained MMBs and MNBs are discussed, with a special focus on challenges and opportunities for their commercialization.
Charge Density Wave and Ferromagnetism in Intercalated CrSBr
Soft chemical intercalation of the van der Waals magnetic semiconductor CrSBr induces a quasi-1D charge density wave (CDW) phase. The combination of this CDW with ferromagnetism from a spin-polarized band generates an unusual coupling of the charge and spin modulations in the intercalated material.
Abstract
In materials with 1D electronic bands, electron–electron interactions can produce intriguing quantum phenomena, including spin-charge separation and charge density waves (CDW). Most of these systems, however, are non-magnetic, motivating a search for anisotropic materials where the coupling of charge and spin may affect emergent quantum states. Here, chemical intercalation of the van der Waals magnetic semiconductor CrSBr yields Li0.17(2)(tetrahydrofuran)0.26(3)CrSBr, which possesses an electronically driven quasi-1D CDW with an onset temperature above room temperature. Concurrently, electron doping increases the magnetic ordering temperature from 132 to 200 K and switches its interlayer magnetic coupling from antiferromagnetic to ferromagnetic. The spin-polarized nature of the anisotropic bands that give rise to this CDW enforces an intrinsic coupling of charge and spin. The coexistence and interplay of ferromagnetism and charge modulation in this exfoliatable material provide a promising platform for studying tunable quantum phenomena across a range of temperatures and thicknesses.
Thermoresponsive solid electrolyte interphase enables safe lithium-sulfur batteries with high energy density
DOI: 10.1039/D5EE00412H, PaperFeng Jiang, Yun-Fei Du, Jia-Xin Guo, Nai-Lu Shen, Zi-Xian Chen, Mei Geng, Dongsheng Ren, Bo-Quan Li, Xue-Qiang Zhang, Tao Wang, Yuan Ma, Yiren Zhong, Jiarui He, Zhi Zhu, Faxing Wang, Jia-Qi Huang, Xin-Bing Cheng, Yuping Wu
The high-activity lithium metal anode limits the practical application of lithium-sulfur batteries in terms of both electrochemical performance and thermal safety. Solid electrolyte interphase (SEI) as a physical barrier between...
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Cross-linked nanoflower network and Se-doping enabling sulfur rich SPAN towards lithium‒sulfur batteries beyond 600 Wh kg‒1
DOI: 10.1039/D5EE00500K, PaperQiang Wu, Yuanke Wu, Hui Yan, Wei Zhong, Mingsheng Qin, Haolin Zhu, Shijie Cheng, Jia Xie
Sulfurized polyacrylonitrile (SPAN) is one of the most promising cathodes for high-energy-density lithium‒sulfur batteries since its distinctive organic skeleton and covalent sulfur storage mechanism effectively prevent polysulfide dissolution and mitigate...
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Combining the use of CO<sub>2</sub> and H<sub>2</sub> networks benefits carbon management in Europe
Nature Energy, Published online: 11 April 2025; doi:10.1038/s41560-025-01753-5
An analysis of European carbon management shows that CO2 and H2 networks can complement each other. Transporting CO2 and H2 from low-cost regions with high availability to areas that process the two molecules into clean fuels or sequester CO2 could reduce total energy system costs by up to 5.3%.H<sub>2</sub> and CO<sub>2</sub> network strategies for the European energy system
Nature Energy, Published online: 11 April 2025; doi:10.1038/s41560-025-01752-6
This study on European carbon management shows how H2 and CO2 networks influence whether CO2 is transported to renewable hubs and sequestration sites or H2 is delivered to industrial sites for producing clean fuels from captured CO2.Inversion of supramolecular chirality by photo-enhanced secondary nucleation
Nature Nanotechnology, Published online: 11 April 2025; doi:10.1038/s41565-025-01882-8
By controlling the contribution of secondary nucleation in the self-assembly of chiral photoswitch molecules using light, it is possible to preferentially generate metastable aggregates, thereby reversing the supramolecular chirality.From small batteries to big claims
Nature Nanotechnology, Published online: 11 April 2025; doi:10.1038/s41565-025-01906-3
In battery research, the areas of the electrodes and cell dimensions affect the energy storage performance. Here the authors discuss the factors that influence the reliability of electrochemical measurements and battery performance in lithium-ion cells with different electrode areas.Locating dislocations in organic crystals
Nature Materials, Published online: 11 April 2025; doi:10.1038/s41563-025-02203-z
The formation of dislocations upon slip–slide events in organic crystals has been revealed by advanced electron microscopy and data-mining techniques.Galvanic Corrosion Underlies Coulombic Efficiency Differences in High-Performing Lithium Metal Battery Electrolytes
DOI: 10.1039/D5EE00071H, PaperSolomon T. Oyakhire, Sang Cheol Kim, Wenbo Zhang, Sanzeeda Baig Shuchi, Yi Cui, Stacey Bent
Current guidelines for electrolyte engineering in lithium metal batteries are based on design metrics such as lithium morphology, electrolyte transport properties, solid electrolyte interphase (SEI) characteristics, and lithium-electrolyte reactivity. In...
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Fluorine-Free Electrolytes in Batteries: Principles, Strategies, and Advances
DOI: 10.1039/D4EE04820B, Review ArticleBoligarla Vinay, Yosef Nikodimos, Tripti Agnihotri, Shadab Ali Ahmed, Teklay Mezgebe Hagos, Rehbar Hasan, Elango Balaji Tamilarasan, Wei-Nien Su, Bing Joe Hwang
Electrolytes play a pivotal role in battery technologies, influencing performance and safety. However, electrolytes containing fluorine present adverse environmental risks due to their high greenhouse gas emissions and caution of...
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Fri 09 May 14:00: Title to be confirmed
Abstract not available
- Speaker: Mikael Rechtsman, Penn State
- Friday 09 May 2025, 14:00-15:00
- Venue: Seminar Room 3, RDC.
- Series: Theory of Condensed Matter; organiser: Gaurav.
Thu 08 May 14:00: Title to be confirmed
Abstract not available
- Speaker: Prof. Nikos Nikiforakis (Cambridge)
- Thursday 08 May 2025, 14:00-15:30
- Venue: Seminar Room 3, RDC.
- Series: Theory of Condensed Matter; organiser: Bo Peng.
High‐Performance 721 nm‐Excitable Photon Upconversion Porous Aromatic Frameworks for Broad‐Range Oxygen Sensing and Efficient Heterogeneous Photoredox Catalysis
High-performance 721 nm-excitable solid upconversion porous aromatic frameworks (UC PAFs) was constructed and applied to a broad-range oxygen sensing and efficient heterogeneous photoredox catalysis. Moreover, homogeneous triple exciton energy is recognized to facilitate exciton diffusion, resulting in a high upconversion quantum yield (1.5% with an upper limit of 50%).
Abstract
The development of long-wavelength excitable solid upconversion materials and the regulation of exciton behavior is important for solar energy harvesting, photocatalysis, and other emerging applications. However, the approaches for regulating exciton diffusion are very limited, resulting in extremely poor photonic upconversion performance in solid-state. Here, the annihilation unit is integrated into porous aromatic frameworks (PAFs) and loaded with photosensitizer to construct efficient 721 nm-excitable solid upconversion material (upconversion quantum yield up to 1.5%, upper limit 50%). Most importantly, we found that the steric hindrance of annihilator units breaks the π-conjugation between the annihilation unit and the PAFs framework to form the homogeneous triplet exciton energy, which is conducive to the exciton diffusion. After increasing the exciton diffusion constant from 2.0 × 10−6 to 1.34 × 10−5 cm2 s−1, the upconversion quantum yield is increased ≈ 50-fold. Further, this solid upconversion material is utilized to demonstrate, for the first time, a broad-range oxygen sensing and 721 nm-driven heterogeneous and recyclable photoredox catalysis. These findings provide an important approach for regulating the behavior of triplet exciton in disorder solid materials to gain better upconversion performance, which will advance practical applications of organic photon upconversion in energy, chemistry, and photonics.
Imaging the 4D Chemical Heterogeneity of Single V2O5 Particles During Charging/Discharging Processes
A spectrally-resolved dual-mode spinning-disk confocal microscopy is developed to monitor the 4D chemical heterogeneity of single V2O5 particles during cycling. A unique and irreversible transformation of V5+ to V3+ on a particle's bottom electric contact points has been unveiled for the first time. The coordination strategy between ethylene diamine tetraacetic acid and V3+ is proposed to inhibit V3+ precipitation effectively.
Abstract
Microparticle cathode materials are widely used in secondary batteries. However, obtaining dynamic chemical heterogeneities of these microparticles is challenging, hindering in-depth mechanistic investigation of the underlying processes. For example, although vanadium pentoxide shows promise as an electrode material for zinc ion batteries, its poor performance's root cause is elusive. Herein, a fluorescence/scattering dual-mode spinning disk confocal microscopy-based approach is developed to visualize the 4D chemical heterogeneity of single V2O5 particles during cycling. Dual-mode in situ imaging identifies valence state changes of vanadium ions with high spatiotemporal resolution. A unique difference is observed between the scattering intensities of a particle's bottom electric contact points and the rest parts during the discharging process. In contrast, fluorescence intensity variation suggests high consistency across the particles. Correlative Raman, UV–Vis spectroscopy, and electrochemical impedance spectroscopy analyses suggest the precipitation of V3+ species at the bottom interface of the V2O5 electrode, leading to increased electron transfer resistance and compromised overall performance. A coordination strategy between ethylene diamine tetraacetic acid and V3+ is proposed for inhibiting V3+ precipitation, and its effectiveness is further verified by imaging and electrochemical impedance spectroscopy analyses. Insights from the imaging approach presented herein will enable the rational design of high-performance batteries.
Achieving >23% Efficiency Perovskite Solar Minimodules with Surface Conductive Coordination Polymer
This study addresses a critical challenge in the commercialization of perovskite solar modules by reducing photovoltage loss through the in situ formation of a surface conductive coordination polymer at the surface/interface of the perovskite film.
Abstract
Despite the reported high efficiencies of small-area perovskite photovoltaic cells, the deficiency in large-area modules has impeded the commercialization of perovskite photovoltaics. Enhancing the surface/interface conductivity and carrier-transport in polycrystalline perovskite films presents significant potential for boosting the efficiency of perovskite solar modules (PSMs) by mitigating voltage losses. This is particularly critical for multi-series connected sub-cell modules, where device resistance significantly impacts performance compared to small-area cells. Here, an effective approach is reported for decreasing photovoltage loss through surface/interface modulation of perovskite film with a surface conductive coordination polymer. With post-treatment of meso-tetra pyridine porphyrin on perovskite film, PbI2 on perovskite film reacts with pyridine units in porphyrins to generate an iso-structural 2D coordination polymer with a layered surface conductivity as high as 1.14 × 102 S m−1, due to the effect of surface structure reconstruction. Modified perovskite film exhibits greatly increased surface/interface conductivity. The champion PSM obtains a record efficiency up to 23.39% (certified 22.63% with an aperture area of 11.42 cm2) featuring only 0.33-volt voltage loss. Such a modification also leads to substantially improved operational device stability.
Evidence of Cation Symmetry Reduction Induced Bulk Photovoltaic Effect in Metal‐Free Perovskite for Efficient Self‐Powered X‐Ray Detection
The relationship between the bulk photovoltaic effect and cation symmetry is systematically investigated, leading to the first realization of a self-powered X-ray detector in metal-free perovskites. Reduced cation symmetry enhances both the dipole moment and crystal polarity, facilitating carrier migration while simultaneously passivating defects. Leveraging the nonlinear photocurrent response mechanism, the X-ray detector achieves ultra-high equivalent sensitivity at zero bias.
Abstract
Metal-free perovskite (MFP) X-ray detectors have attracted attention due to biocompatibility and synthesizability. However, the necessity of high voltages for MFP X-ray detectors affects stability and safety. Although, the bulk photovoltaic effect (BPVE) with spontaneous electric field is a potential alternative for X-ray detection without high voltage, the constitutive relationship of BPVE in MFP remains unclear. Herein, the relationship between BPVE and cation symmetry is explored, and a self-powered X-ray detector is realized by BPVE in MFP for the first time. Theoretical studies show that cation symmetry reduction can distort the halide octahedron in one direction, which increases the dipole moment and crystal polarity to induce BPVE. The electric field from crystal polarity can drive the defect passivation by the equilibrium carrier and enhance the nonequilibrium carrier performance for BPVE. Then, polar MFP (mPAZE-NH4Br3 H2O) with excellent BPVE is designed. Due to the nonlinear response, the detector obtains a numerically recorded equivalent sensitivity (≈103 µC Gyair −1 cm−2) at 0 V. Moreover, the imaging performance is demonstrated and two image convolution kernels for it are constructed. Finally, it features continuous operation (20000 s) and temperature stability (-55–250 °C). It is believed that the method will further drive the application of MFP for X-ray detectors.