European Journal of Physics

AbstractAqueous zinc ion batteries (AZIBs) face challenges due to the limited interface stability of Zn anode, which includes uncontrolled hydrogen evolution reaction (HER) and excessive dendrite growth. In this study, a natural binary additive composed of saponin and anisaldehyde is introduced to create a stable interfacial adsorption layer for Zn protection via reshaping the electric double layer (EDL) structure. Saponin with rich hydroxyl and carboxyl groups serves as “anchor points”, promoting the adsorption of anisaldehyde through intermolecular hydrogen bonding. Meanwhile, anisaldehyde, with a unique aldehyde group, enhances HER suppression by preferentially facilitating electrocatalytic coupling with H* in the EDL, leading to the formation of a robust inorganic solid electrolyte interphase that prevents dendrite formation, and structural evolution of anisaldehyde during Zn deposition process is verified. As a result, the Zn||Zn symmetric cells present an ultra‐long cycling lifespan of 3 400 h at 1 mA cm−2 and 1 700 h at 10 mA cm−2. Even at the current density of 20 mA cm−2, the cells demonstrate reversible operations for 450 h. Furthermore, Zn‐ion hybrid capacitors exhibit a remarkable lifespan of 100 000 cycles. This work presents a simple synergetic strategy to enhance anode/electrolyte interfacial stability, highlighting its potential for Zn anode protection in high‐performance AZIBs.

AbstractOxide ions in lithium‐rich layered oxides can store charge at high voltage and offer a viable route toward the higher energy density batteries. However, the underlying oxygen redox mechanism in such materials still remains elusive at present. In this work, a precise in situ magnetism measurement is employed to monitor real‐time magnetization variation associated with unpaired electrons in Li1.2Mn0.6Ni0.2O2 cathode material, enabling the investigation on magnetic/electronic structure evolution in electrochemical cycling. The magnetization gradually decreases except for a weak upturn above 4.6 V during the initial charging process. According to the comprehensive analyses of various in/ex situ characterizations and density functional theory (DFT) calculations, the magnetization rebound can be attributed to the interaction evolution of lattice oxygen from π‐type delocalized Mn─O coupling to σ‐type O─O dimerization bonding. Moreover, the magnetization amplitude attenuation after long‐term cycles provides important evidence for the irreversible structure transition and capacity fading. The oxygen redox mechanism concluded by in situ magnetism characterization can be generalized to other electrode materials with an anionic redox process and provide pivotal guidance for designing advanced high‐performance cathode materials.

AbstractRare‐earth afterglow materials, with their unique light‐storage properties, show great promise for diverse applications. However, their broader applicability is constrained by challenges such as poor solvent compatibility, limited luminescent efficiency, and monochromatic emissions. In this study, these limitations are addressed by blending ZnS with various rare‐earth phosphors including (Sr0.75Ca0.25)S:Eu2+; SrAl2O4:Eu2+, Dy3+ and Sr2MgSi2O7:Eu2+, Dy3+ to modulate deep trap mechanisms and significantly enhance both the afterglow and light capture capabilities. Using electrospinning, a large‐area (0.4 m × 3 m) afterglow film is successfully fabricated with tunable colors and an extended afterglow duration exceeding 30 h. This film demonstrates thermoluminescence, enabling potential integration into fire‐rescue protective clothing for enhanced emergency visibility. In greenhouse settings, it effectively supports chlorophyll synthesis and optimizes conditions for plant growth over a 24‐h cycle. For tunnel and garage applications, the film captures and stores light from vehicle headlights at distances of up to 70 meters. The scalability and cost‐effectiveness of this afterglow film underscore its considerable potential for real‐world applications across multiple fields, marking a significant advancement in sustainable illumination technology.

AbstractOrganic luminescent radicals possess considerable potential for applications in organic light‐emitting diodes (OLEDs)‐based visible light communication owing to their intrinsic advantages of nanosecond emission lifetimes and spin‐allowed radiative transitions. However, the inherently narrow energy bandgap and multiple nonradiative channels of organic radicals make it difficult to achieve efficient green and blue light‐emitting, which is not conducive to applying visible light communication in diverse fields. In this study, a series of carbon‐centered radicals derived from N‐heterocyclic carbenes are designed and synthesized, some of which exhibiting hybrid local and charge‐transfer (HLCT) states that resulting in efficient green emission. The results of photophysical characterizations and theoretical calculations demonstrate that the luminescence efficiency is closely related to their emission states. This relationship inhibits the nonradiative channels while simultaneously opening the radiative channels of organic radicals exhibiting HLCT states but not those with locally excited states. Intriguingly, a high photoluminescence quantum yield value of up to 70.1% at 534 nm is observed, which is the highest among green light‐emitting carbon‐centered radicals reported to date. Based on this exceptional result, an OLED device is fabricated and achieved an external quantum efficiency of 8.8%. These results demonstrate its potential application in electroluminescent devices.

AbstractThe application of perovskite photovoltaics is hampered by issues related to the operational stability upon exposure to external stimuli, such as voltage bias and light. The dynamic control of the properties of perovskite materials in response to light could ensure the durability of perovskite solar cells, which is especially critical at the interface with charge‐extraction layers. We have applied a functionalized photochromic material based on spiro‐indoline naphthoxazine at the interface with hole‐transport layers in the corresponding perovskite solar cells with the aim of stabilizing them in response to voltage bias and light. We demonstrate photoinduced transformation by a combination of techniques, including transient absorption spectroscopy and Kelvin probe force microscopy. As a result, the application of the photochromic derivative offers improvements in photovoltaic performance and operational stability, highlighting the potential of dynamic photochromic strategies in perovskite photovoltaics.

AbstractVoltage‐driven ion motion offers a powerful means to modulate magnetism and spin phenomena in solids, a process known as magneto‐ionics, which holds great promise for developing energy‐efficient next‐generation micro‐ and nano‐electronic devices. Synthetic antiferromagnets (SAFs), consisting of two ferromagnetic layers coupled antiferromagnetically via a thin non‐magnetic spacer, offer advantages such as enhanced thermal stability, robustness against external magnetic fields, and reduced magnetostatic interactions in magnetic tunnel junctions. Despite its technological potential, magneto‐ionic control of antiferromagnetic coupling in multilayers (MLs) has only recently been explored and remains poorly understood, particularly in systems free of platinum‐group metals. In this work, room‐temperature voltage control of Ruderman–Kittel–Kasuya–Yosida (RKKY) interactions in Co/Ni‐based SAFs is achieved. Transitions between ferrimagnetic (uncompensated) and antiferromagnetic (fully compensated) states is observed, as well as significant modulation of the RKKY bias field offset, emergence of additional switching events, and formation of skyrmion‐like or pinned domain bubbles under relatively low gating voltages. These phenomena are attributed to voltage‐driven oxygen migration in the MLs, as confirmed through microscopic and spectroscopic analyses. This study underscores the potential of voltage‐triggered ion migration as a versatile tool for post‐synthesis tuning of magnetic multilayers, with potential applications in magnetic‐field sensing, energy‐efficient memories and spintronics.

AbstractQuasi 2D layered metal halide perovskites (2D‐LMHPs) with natural quantum wells (QWs) structure have garnered significant attention due to their excellent optoelectronic properties. Doping rare earth (RE) ions with 4fn inner shell emission levels can largely expand their optical and optoelectronic properties and realize diverse applications, but has not been reported yet. Herein, an efficient Yb3+‐doped PEA2Cs2Pb3Br10 quasi 2D‐LMHPs is fabricated and directly identified the Yb3+ ions in the quasi 2D‐LMHPs at the atomic scale using aberration electron microscopy. The interaction between different n phases and Yb3+ ions is elucidated using ultrafast transient absorption spectroscopy and luminescent dynamics, which demonstrated efficient, different time scales and multi‐channel energy transfer processes. Finally, through phase distribution manipulation and surface passivation, the optimized film exhibits a photoluminescence quantum yield of 144%. This is the first demonstration of quantum cutting emission in pure Br‐based perovskite material, suppressing defect states and ion migration. The efficient and stable near‐infrared light‐emitting diodes (NIR LED) is fabricated with a peak external quantum efficiency (EQE) of 8.8% at 990 nm and the record lifetime of 1274 min. This work provides fresh insight into the interaction between RE ions and quasi 2D‐LMHPs and extend the function and application of quasi 2D‐LMHPs materials.

AbstractPrecisely optimizing the electronic metal support interaction (EMSI) of the electrocatalysts and tuning the electronic structures of active sites are crucial for accelerating water adsorption and dissociation kinetics in alkaline hydrogen evolution reaction (HER). Herein, an effective strategy is applied to modify the electronic structure of Ru nanoparticles (RuNPs) by incorporating Ru single atoms (RuSAs) and Ru and Cr atomic pairs (RuCrAPs) onto a nitrogen‐doped carbon (N–C) support through optimized EMSI. The resulting catalyst, RuNPs‐RuCrAPs‐N‐C, shows exceptional performance for alkaline HER, achieving a six times higher turnover frequency (TOF) of 13.15 s⁻¹ at an overpotential of 100 mV, compared to that of commercial Pt/C (2.07 s⁻¹). Additionally, the catalyst operates at a lower overpotential at a current density of 10 mA·cm⁻2 (η10 = 31 mV), outperforming commercial Pt/C (η10 = 34 mV). Experimental results confirm that the RuCrAPs modified RuNPs are the main active sites for the alkaline HER, facilitating the rate‐determining steps of water adsorption and dissociation. Moreover, the Ru–Cr interaction also plays a vital role in modulating hydrogen desorption. This study presents a synergistic approach by rationally combining single atoms, atomic pairs, and nanoparticles with optimized EMSI effects to advance the development of efficient electrocatalysts for alkaline HER.

AbstractCovalent organic frameworks (COFs) are emerging as a transformative platform for photocatalytic hydrogen peroxide (H2O2) production due to their highly ordered structures, intrinsic porosity, and molecular tunability. Despite their potential, the inefficient utilization of photogenerated charge carriers in COFs significantly restrains their photocatalytic efficiency. This study presents two regioisomeric COFs, α‐TT‐TDAN COF and β‐TT‐TDAN COF, both incorporating thieno[3,2‐b]thiophene moieties, to investigate the influence of regioisomerism on the excited electron distribution and its impact on photocatalytic performance. The β‐TT‐TDAN COF demonstrates a remarkable solar‐to‐chemical conversion efficiency of 1.35%, outperforming its α‐isomeric counterpart, which is merely 0.44%. Comprehensive spectroscopic and computational investigations reveal the critical role of subtle substitution change in COFs on their electronic properties. This structural adjustment intricately connects molecular structure to charge dynamics, enabling precise regulation of electron distribution, efficient charge separation and transport, and localization of excited electrons at active sites. Moreover, this finely tuned interplay significantly enhances the efficiency of the oxygen reduction reaction. These findings establish a new paradigm in COF design, offering a molecular‐level strategy to advance COFs and reticular materials toward highly efficient solar‐to‐chemical energy conversion.

AbstractRegenerative fuel cells hold significant potential for efficient, large‐scale energy storage by reversibly converting electrical energy into hydrogen and vice versa, making them essential for leveraging intermittent renewable energy sources. However, their practical implementation is hindered by the unsatisfactory efficiency. Addressing this challenge requires the development of cost‐effective electrocatalysts. In this study, a carbon nanotube (CNT)‐supported RuNi composite with low Ru loading is developed as an efficient and stable catalyst for alkaline hydrogen and oxygen electrocatalysis, including hydrogen evolution, oxygen evolution, hydrogen oxidation, and oxygen reduction reaction. Furthermore, a regenerative fuel cell using this catalyst composite is assembled and evaluated under practical relevant conditions. As anticipated, the system exhibits outstanding performance in both the electrolyzer and fuel cell modes. Specifically, it achieves a low cell voltage of 1.64 V to achieve a current density of 1 A cm−2 for the electrolyzer mode and delivers a high output voltage of 0.52 V at the same current density in fuel cell mode, resulting in a round‐trip efficiency (RTE) of 31.6% without further optimization. The multifunctionality, high activity, and impressive RTE resulted by using the RuNi catalyst composites underscore its potential as a single catalyst for regenerative fuel cells.

AbstractRecent advancements in alloy catalysis have yield novel materials with tailored functionalities. Among these, Cu‐based single‐atom alloy (SAA) catalysts have attracted significant attention in catalytic applications for their unique electronic structure and geometric ensemble effects. However, selecting alloying atoms with robust dispersion stability on the Cu substrate is challenging, and has mostly been practiced empirically. The fundamental bottleneck is that the microscopic mechanism that governs the dispersion stability is unclear, and a comprehensive approach for designing Cu‐based SAA systems with simultaneous dispersion stability and high catalytic activity is still missing. Here, combining theory and experiment, a simple yet intuitive d‐p orbital matching mechanism is discovered for rapid assessment of the atomic dispersion stability of Cu‐based SAAs, exhibiting its universality and extensibility for screening effective SAAs across binary, ternary and multivariant systems. The catalytic selectivity of the newly designed SAAs is demonstrated in a prototype reaction‐acidic CO2 electroreduction, where all SAAs achieve single‐carbon product selectivity exceeding 70%, with Sb1Cu reaching a peak CO faradaic efficiency of 99.73 ± 2.5% at 200 mA cm−2. This work establishes the fundamental design principles for Cu‐based SAAs with excellent dispersion stability and selectivity, and will boost the development of ultrahigh‐performance SAAs for advanced applications such as electrocatalysis.

AbstractRheumatoid arthritis (RA) is a chronic autoimmune disease characterized by excessive inflammation, pathological bone resorption, and systemic osteoporosis. It lacks effective treatment due to the complex pathogenesis. Gene therapy, especially targeted oligonucleotide (ON) delivery therapy, offers a new prospect for the precise treatment of RA. Nevertheless, the clinical application of ON delivery therapy still faces various challenges such as the rapid enzymolysis by RNAse, the lack of tissue targeting ability, difficulty in cell membrane penetration, and the incapability of endolysosomal escape. To address these issues, a novel kind of engineered peptide and oligonucleotide (PON) nanohybrids are designed and fabricated, which provide various advantages including good biosafety, inflammatory region‐targeted delivery, cell membrane penetration, reactive oxygen species (ROS) scavenging, and endolysosomal escape. The PON nanohybrids produce promising effects in suppressing inflammatory responses and osteoclastogenesis of macrophages via multiple signaling pathways. In vivo administration of PON nanohybrids not only ameliorates local joint bone destruction and systemic osteoporosis in the pathological state, but also demonstrates good prophylactic effects against the rapid progression of RA disease. In conclusion, the study presents a promising strategy for precise RA treatment and broadens the biomedical applications of gene therapy based on delivery system.

AbstractFe2+ have emerged as the ideal charge carriers to construct aqueous batteries as one of the most competitive candidates for next‐generation low‐cost and safe energy storage. Unfortunately, the fast oxidation of Fe2+ into Fe3+ at ambient conditions inevitably requires the assembly process of the cells in an oxygen‐free glovebox. Up to date, direct air assembly of aqueous Fe‐ion battery remains very desirable yet highly challenge. Here oxidation of Fe2+ is found at ambient condition and is completely inhibited in an acidic electrolyte. A proton/O2 competitive mechanism in the acidic electrolyte is revealed with reduced coordinated O2 in the Fe2+ solvated shell for this unexpected finding. Based on this surprise, for the first time, air‐operated assembly of iron‐ion batteries is realized. Meanwhile, it is found that the acidic environment induces the in situ growth of active α‐FeOOH derivate on the VOPO4·2H2O surface. Strikingly, the acidic electrolyte enables an air‐operated Fe‐ion battery with a high specific capacity of 192 mAh g−1 and ultrastable cycling stability over 1300 cycles at 0.1 A g−1. This work makes a break through on the air‐assembly of Fe‐ion battery without oxygen‐free glovebox. It also reveals previously unknown proton/O2 competitive mechanisms in the Fe2+ solvated shell and cathode surface chemistry for aqueous Fe2+ storage.

AbstractPreoperative neoadjuvant radio‐chemotherapy is a cornerstone in the treatment of low rectal cancer, yet its effectiveness can be limited by the insensitivity of some patients, profoundly impacting their quality of life. Through preliminary research, it is found that TREM2+ macrophages play a pivotal role in the non‐responsiveness to immunotherapy. To address this challenge, a novel ionizing radiation‐responsive delivery system is developed for the precise expression of anti‐TREM2 single‐chain antibody fragments (scFv) using an engineered probiotic, Escherichia coli Nissle 1917 (EcN), to modulate immunotherapy. The released anti‐TREM2 scFv can be precisely targeted and delivered to the tumor site via the engineered EcN outer membrane vesicles (OMVs), thereby reversing the immunosuppressive tumor microenvironment and enhancing tumor therapeutic efficiency when used in combination with the αPD‐L1 immune checkpoint inhibitor. Additionally, these engineered bacteria can be further modified to enhance the intestinal colonization capabilities through oral administration, thereby regulating the gut microbiota and its metabolic byproducts. Consequently, the ionizing radiation‐responsive drug delivery system based on the engineered bacteria not only introduces a promising new therapeutic option for low rectal cancer but also showcases the potential to finely tune immune responses within the intricate tumor microenvironment, paving the way for innovative strategies in tumor radio‐immunotherapy.