The electrochemical oxygen evolution reaction (OER) is a critical reaction to produce chemical fuels from electricity. So far, many studies have reported the influence of electrolytes on the OER efficiency. However, enhancing the activity by strategically tuning the electrolyte remains challenging, because the interaction between the electrocatalyst and electrolyte ions are still ambiguous. Here, we show that the OER activity of nanochanneled manganese oxide (alpha-MnO2) is enhanced in the presence of K+ compared to Na+ in a pH 13 alkaline electrolyte. We attribute the pronounced electrolyte dependence to cation intercalation within the nanochannels of alpha-MnO2, because the cation dependence was markedly suppressed for gamma-MnO2 whose channels are too small for intercalation. Ultraviolet photoelectron spectroscopy (UPS) analysis revealed that the valence band position of alpha-MnO2 shifts depending on the cation present during electrolysis. However, no changes could be observed using gradient-incidence X-ray diffraction (GI-XRD) or conversion electron yield-extended X-ray absorption fine structure (CEY-EXAFS) analysis, despite these techniques being more surface-sensitive (probe depth: approximately 100 nm) than standard XRD or EXAFS. These results indicate that structural changes are localized to the surface of alpha-MnO2, occurring only at scales near the UPS probe depth of approximately 10 nm. The shift of the valence band position within the UPS spectra, along with the minimal change in the average oxidation state based on X-ray photoelectron spectroscopy (XPS), indicate that the Mn 3d orbitals of alpha-MnO2 are stabilized in the presence of K+. This would enhance the electrophilicity and reactivity of surface oxyl species, thus promoting O-O bond formation. Our study highlights the importance of optimizing not only the ions in the electrolyte but also their interaction with nanoscale structures in the electrode material.

Molecular assemblies that form distinct out-of-equilibrium states in response to varying energy inputs represent a promising platform for designing advanced, autonomous adaptive materials capable of flexibly and diversely responding to environmental stimuli. Herein, we describe a supramolecular polymer system that integrates azobenzene photoisomerization with hydrogen-bond-directed supramolecular polymorphism, enabling the formation of distinct out-of-equilibrium states under varied light intensities. trans isomers of an azobenzene derivative featuring a barbituric acid merocyanine unit self-assemble into lamellar crystals via two-dimensional nanosheet stacking. Ultraviolet light irradiation of a nanosheet dispersion in nonpolar media at different intensities modulates the proportion of cis isomers, eliciting unique out-of-equilibrium states. Specifically, a strong light facilitates the coassembly of trans and cis isomers into one-dimensional nanofibers through hydrogen bond rearrangement, whereas weaker light drives Ostwald ripening, transforming two-dimensional nanosheets into three-dimensional multilayered structures. High-speed atomic force microscopy reveals the intricate dynamic processes driving these transitions.

Ferroelectric halide perovskites provide a fertile platform for optoelectronic functions based on the bulk photovoltaic effect, where broken inversion symmetry couples with quantum geometry of wave functions. The most prominent manifestation is the shift current, second-order nonlinear photocurrent arising from change in the Berry connection during optical transitions. Here we report a gigantic shift current response in epitaxial thin films of a lead-free ferroelectric halide perovskite CsGeI3. High-quality films grown by molecular beam epitaxy exhibit clear hallmarks of shift current, including spectral sign reversals, light-polarization dependence, and reversible electric-field modulation associated with switchable ferroelectric polarization. Remarkably, the normalized shift current magnitude surpasses those ever reported for other compounds by more than an order of magnitude, establishing a benchmark for bulk photovoltaic performance. These results identify ferroelectric halide perovskites as a powerful platform for exploring quantum-geometry-driven photoresponses and open a pathway toward next-generation photovoltaic and nonlinear optoelectronic technologies beyond the conventional junction-based architectures.

Nonreciprocity, the asymmetry of transport, underlies technologies from the diode to the microwave isolator. In a ferromagnet, a surface acoustic wave generates an elliptical effective field with propagation-locked handedness, breaking the reciprocity of its propagation. Despite decades of study on this phenomenon, a method for controlling the sign of the nonreciprocity has remained elusive. Here we observe a sign reversal in Ni_xFe_100-x films. A 0.8 at.

ABSTRACT Solid‐state cross‐coupling is a promising synthetic strategy, enabling green processes and access to otherwise unattainable products. To date, avoiding the harsh mechanical force while achieving the synthesis of highly insoluble materials under mild, additive‐free, and solid‐state conditions remains a challenge especially if heterogeneous catalysis is considered. Inspired by the fundamental diffusion dynamics observed in nature, we developed a polymeric palladium‐catalyzed quasi‐solid‐state Suzuki–Miyaura reaction that proceeds without mechanical input; that is, a granular motion of the components results from heat‐induced convection‐driven mass transfer. This approach enabled the synthesis of various polycyclic aromatic hydrocarbons and functional materials in up to 93% yields with Pd loadings as low as 500 mol ppm. Gram‐scale synthesis of dinaphthyl anthracene as a functional material was successfully achieved under the quasi‐solid‐state reaction conditions. Notably, since no mechanical force is applied during the reaction, it is well‐suited to be analyzed in real time, which is a challenge in solid‐state systems. As a result, in‐situ monitoring of the chemical changes of each of the solid reactants allowed the identification and real time monitoring of a boronate intermediate. In addition, direct microscopic visualization revealed changes in morphology and element distributions, proposing a granular motion mechanism for this transformation.

This study details a highly significant improvement in the synthesis of 1,6-disila[4.4.4]propellane (1) through the implementation of a mechanistically rationalized fluorosilane route. This efficiency represents a more than 20-fold enhancement over the previously reported method (4% yield). Structural analysis by single-crystal X-ray diffraction revealed its unique columnar packing arrangement in the solid state.

Accurately decoupling mechanical stimuli and environmental factors such as humidity remains a major challenge in the development of tactile sensors, as cross-interference of these stimuli in sensing signals leads to reduced measurement accuracy and reliability. To address this, we present a distinct ion-electron charge transport-driven sensing mechanism that decouples pressure and humidity under simultaneous hygromechanical conditions. To exploit the distinct charge transport kinetics of ions and electrons, we designed a biphasic dual-conductive elastomer (BiDCE). Through phase separation between ionically and electronically conductive domains, BiDCE achieves multimodal sensing ability without cross-interference between sensing signals. In addition, an impedance spectroscopy-based decoupling method, developed based on the charge transport kinetics of BiDCE, enables real-time quantification of hygromechanical stimuli. The fabricated hygromechanical sensor was integrated into a self-adaptive robotic hand, enabling the simultaneous detection of both contact (pressure) and non-contact (proximity) states of human hands and fingers. This system ensures precise grip control while maintaining safe human-machine interaction and represents a significant advancement in multimodal tactile sensors for robotic skin interfaces.

Two-coordinate plumbyliumylidene ions constitute a rare class of highly electron-deficient cationic Pb(II) species. Herein, we report the synthesis and structural characterization of iminophosphonamido-supported plumbyliumylidene ions bearing two different borate counteranions, {B[(4-tBuMe2Si)C6F4]4}- and [B(C6F5)4]-. Single-crystal X-ray analyses reveal pronounced ion-pairing effects that depend on the counteranion, including secondary Pb···F interactions and solvent coordination, highlighting the high Lewis acidity of the lead center. The [B(C6F5)4]- salt exhibits versatile Lewis acid catalysis, enabling living ring-opening polymerization of ε-caprolactone and L-lactide to afford well-defined polymers and PCL-block-PLA copolymers. In addition, the same cationic Pb(II) species catalyzes the hydroamination of alkynes with distinct chemoselectivity, suppressing double hydroamination relative to three-coordinate analogues. These results establish two-coordinate plumbyliumylidenes as powerful and tunable main group Lewis acid catalysts.

We report the carrier-density dependence of the magnetotransport property in the correlated Dirac semimetal CaIrO3. In the dilute carrier density region (n(H) similar to 2.2 & times; 10(16) cm(-3)) at 2 K, the mobility exceeds 1.0 & times; 10(5) cm(2)/Vs at 2 K, and the transverse magnetoresistance reaches 2000% at 12 T. The analysis of quantum oscillations and Hall conductivity shows that the Fermi velocity is nearly independent of the cross-sectional area of the Fermi surface, or equivalently the carrier density, supporting a k-linear dispersion of the Dirac node. The field dependence of magnetoresistivity is nearly B-linear in the moderate carrier density region (n(H) >= 4 & times; 10(16) cm(-3)), but scales with B-alpha(alpha > 2) in the lower carrier density region. The variation of magnetoresistivity is likely affected by the enhanced long-range Coulomb interaction in the quantum limit, where Dirac electrons are subject to the magnetic confinement.

Multinuclear Ru complexes connected by multitopic ligands were central in the development of electron transfer theories. Infinite coordination frameworks constructed from these motifs could inherit their unique electron delocalization and spectroscopic properties, allowing to systematically explore their correlation in the solid-state. However, controlling the crystallization of Ru-based frameworks continues to present a major hurdle. Herein, four nitrogen-based heterocyclic ligands of different lengths were used to construct a series of metal-organic frameworks (MOFs) with the general formula [Ru(L)2Cl2], L = pyrazine (pz), 2,6-naphthyridine (naph), 4,4'-bipyridine (bipy), and 1,4-di(4-pyridyl)-benzene (bpbn). Structural analysis revealed two-dimensional square grid connectivity with the ligand length governing layer packing and interpenetration. The existence of electronic delocalization through the framework backbones was confirmed using electrochemical and spectroscopic techniques. Mixed-valent states of Ru-MOFs were generated by controlled chemical oxidation using tris(4-bromophenyl)ammoniumyl hexachloroantimonate. The resultant samples featured intervalence charge transfer (IVCT) bands, which were dependent on the oxidation state and were accompanied by 4-orders-of-magnitude enhancement of conductivity. The mixed-valent states of Ru-naph and Ru-bipy exhibited the highest conductivities, reaching 2.35 × 10-5 and 5.91 × 10-6 S/cm, respectively. Interrogation of these frameworks offered valuable insights into the interplay between the IVCT transitions and the electronic conductivity.

Skin impedance reflects both the barrier function and psychophysiological state of the human body, but long-term monitoring remains challenging due to the lack of electrodes that simultaneously offer water resistance, stretchability, and breathability. In this study, we developed poly(vinyl alcohol)/waterborne polyurethane (PVA/WBPU) blend nanomesh electrodes with controlled polymer composition to address these requirements. Electrospinning produced nanofibers with an island-sea morphology, where partial dissolution of PVA enabled temporary skin adhesion while residual WBPU maintained structural integrity. The optimized PVA/WBPU = 5/5 electrodes showed minimal resistance increase (1.02-fold) after 24 h of continuous water flow and retained conductivity under 80% strain and after 1000 stretch cycles. When applied to the palm, they maintained stable resistance ( < 50 Omega) for at least 4 h, whereas PVA-only electrodes frequently exhibited resistance increases above 1 k Omega or electrical disconnection. These results indicate that controlling the PVA/WBPU blending ratio ensures mechanical and electrical stability while preserving breathability, establishing a materials design strategy for long-term, skin-conformable, and breathable bioelectronic interfaces.

The presence of atomic vacancies in a close‐packed material is believed to allow the migration of atoms adjacent to the vacancies, which induces dynamics of atoms. However, it is not known whether atoms in discrete molecules can undergo vacancy‐induced dynamics. We describe herein the generation of a close‐packed Pd12 cluster complex [Pd12(C7H7)6][B(ArF)4]n (n = 2, 3) with a Pd‐atom vacancy, and the observation of the diffusion of Pd atoms. Variable‐temperature NMR analysis, X‐ray structure analysis, and theoretical calculations indicate that an atomic vacancy is located at the surface sites of the Pd12 core, and that it migrates rapidly on the NMR timescale. This means that all 11 palladium atoms at the surface undergo self‐diffusion with a low energy barrier. These results demonstrate, for the first time, that atomic diffusion occurs within a molecule through the vacancy mechanism.

Van der Waals heterostructures have been used to tailor atomic layers into various artificial materials through interactions at heterointerfaces. The interplay between the band gap created by the band folding of the interfacial potential and the band inversion driven by enhanced spin-orbit interaction (SOI) through band hybridization enables us to realize a two-dimensional topological insulator (2D-TI). Here we report the realization of graphene 2D-TIs by epitaxial growth of three-dimensional topological insulator (3D-TI) BiSbTeSe_2 ultrathin films on graphene. By increasing the BiSbTeSe_2 thickness from 2 nm to 9 nm to enhance SOI on graphene, the electronic state is altered from the trivial Kekulé insulator to the 2D-TI. The nonlocal transport reveals the helical edge conduction which survives up to 200 K at maximum. Our graphene 2D-TI is stable, easy to make electrical contacts, and of high quality. It offers various applications including spin-current conversion and platforms for Majorana fermions in junctions to superconductors.

The reactions of the Rind‐based 1,2‐dihalodigermenes, (Eind)BrGe=GeBr(Eind) (1a) and (EMind)ClGe=GeCl(EMind) (1b), with two types of N‐heterocyclic carbenes (NHCs) (Im‐iPr2Me2 and Im‐Me4) resulted in the formation of the halogermylene mono‐NHC adducts, (Im‐iPr2Me2)(Eind)GeBr (2a') and (Im‐iPr2Me2)(EMind)GeCl (2b'), and the germyliumylidene cation bis‐NHC adducts, [(Im‐Me4)2(Eind)Ge]+[Br–] (3a) and [(Im‐Me4)2(EMind)Ge]+[Cl–] (3b). The resulting Ge(II) species are stabilized by the bulky Rind groups and the strongly σ‐donating NHC ligands, whose structures were confirmed by a single‐crystal X‐ray diffraction (SC‐XRD) analysis. Based on DFT and QTAIM calculations of 2a' and the cationic part of 3a, it was concluded that while the Ge–C(Eind) and Ge–C(NHC) bonds exhibit distinct differences in their degrees of polarization, all the Ge–C bonds display a partially polarized covalent character. Both reaction energy calculations and experimental studies suggested the potential liberation of an NHC ligand from the germyliumylidene cation bis‐NHC adducts, leading to the exchange of the NHC ligands. The formation mechanism of 3a from 1a and two NHC molecules via (Im‐Me4)(Eind)GeBr (2a) is discussed based on DFT calculations.

The Creutz-Taube ion, [(NH3)5RuII(mu-pz)RuIII(NH3)5]5+ (pz = pyrazine) is a prominent example of multinuclear Ru systems, which exists in a mixed-valence state. Previous research efforts to interrogate the properties of this complex uncovered important knowledge regarding intramolecular charge transfer between strongly interacting metal centers. In this work, the Ru coordination with pyrazine was extended into two dimensions to create a [Ru(pz)2Cl2] n (Ru-pz) metal-organic framework (MOF). Both solvothermal and solvent-free synthetic methodologies were explored to optimize crystallinity and phase-purity. The detailed structural analysis using single-crystal and powder X-ray diffraction techniques, as well as X-ray absorption spectroscopy and total X-ray scattering confirmed the layered framework structure. In addition, an isostructural Os analogue could also be obtained. The spectroscopic and electrochemical properties of the resultant materials were assessed, which confirmed the existence of mixed-valence states and electronic delocalization between metal centers. This phenomenon facilitated electron propagation in solid-state with conductivity values of some samples reaching the semiconductor range of 10-7-10-4 S/cm. These findings expand the well-established chemistry of discrete mixed-valent Ru complexes into the field of MOFs providing useful insights for further development of these systems.

Some one-dimensional (1D) crystals containing a screw dislocation along their longer axis exhibit a helical twist due to lattice strain. These chiral structures have been thoroughly investigated by using transmission electron microscopy. However, whether two-dimensional (2D) crystals with a spiral surface pattern, presumably containing a screw dislocation, are structurally chiral remains unclear because their internal structures are not visible. Here, we report that a particular 2D crystal with a spiral surface pattern emits circularly polarized luminescence despite comprising achiral building blocks. Comprehensive X-ray structural analysis of this 2D crystal reveals a helical structure with an achiral space group featuring distinctive twinning. This twinned 2D crystal consists of four centrosymmetric components. Applying the twin law to these four achiral components results in a spirally arranged topology, leading to the emergence of chirality in the 2D crystals.

Tin chalcogenide nanocrystals (NCs), particularly tin(II) sulfide (SnS), hold promise for environmentally benign optoelectronic applications. However, challenges such as scalable synthesis, susceptibility to oxidation, and unclear reaction mechanisms hinder further research and limit the exploration of their electronic properties. This study presents a single ligand-controlled hot-injection strategy to synthesize monodisperse pi-SnS NCs (4.7-8.5 nm) with unprecedented size uniformity and long-term stability (>1 year). By systematically optimizing precursor mole ratios (Sn/S up to 4:1) and adjusting solvent composition (reducing 1-octadecene (ODE) volume to <= 1.84 mL), we achieved narrow size distributions (standard deviation of 0.4-0.7 nm) and suppressed phase impurities, overcoming the limitations of conventional hot-injection methods that rely on multiple ligands. The synthesis advances demonstrated optoelectronic properties: size-dependent quantum confinement (band gap tuning via NC diameter) and p-type behavior in NC thin films treated with ligand 1,2-ethanedithiol (EDT). These findings provide a scalable, single-ligand synthesis framework for pi-SnS NCs, resolving challenges in reproducibility and stability while opening pathways for eco-friendly NC-based electronics.

The controlled supramolecular alignment of atomically precise metal nanoclusters is a promising method to unlock unprecedented properties and advanced functions beyond those of the individual monomeric nanoclusters. Conventional protocols for the construction of such assemblies require the use of two or more types of ligands for protecting and interconnecting the nanoclusters, respectively. Herein, a strategy is demonstrated for the hierarchical self‐assembly of an alkyne‐protected silver nanocluster into a 3D network in the crystalline lattice based on cooperative silver···acetylene coordination and silver···pyridyl coordination by a bifunctional ligand with a simple design. The bent ligand L produces a Cl@Ag14L12 monomer with a helical conformation resembling that of organic tripodal ligands, which assembles into a 3D network as evident from a single‐crystal X‐ray diffraction analysis. The monomeric and network structures are further characterized using grazing‐incidence small‐angle X‐ray scattering, atomic force microscopy, X‐ray photoelectron spectroscopy, and X‐ray absorption fine structure, in addition to photoluminescence with a microsecond lifetime in the solid state, exhibiting the success of the strategy toward the design of self‐assembled 3D supramolecular arrangements of atomically precise metal nanoclusters using a single, simple ligand.

Although metal sulfides are promising catalysts for the electrochemical carbon dioxide (CO2) reduction reaction, repulsion between the lone pair of oxygen electrons of CO2 and the electronic clouds of surface sulfur atoms is considered to impede the reaction. Nitrogen introduction is one potential solution to this problem; however, the optimal ratio of sulfur to nitrogen has yet to be determined, and the enhanced reaction products that have been reported to date are limited to carbon monoxide (CO) and formic acid. In this work, copper sulfide (Cu2S) and copper nitride (Cu3N) composites with varying sulfur-to-nitrogen ratios are synthesized with the objective of enhancing the catalytic activity of the CO2 reduction reaction to methane (CH4). 4.20 mol% sulfur-containing Cu3N exhibits a Faradaic efficiency for CH4 production that is higher than that of all examined catalysts including bare Cu3N and Cu2S. The results of in situ Fourier-transform infrared spectroscopy suggests that increased electron donation from the catalyst to the *CO intermediate by the introduction of sulfur into Cu3N shifts the selectivity of the reaction pathway from CO to CH4 production. Taken together, the present findings demonstrate that sulfide-nitride composite structures can function as effective CO2 reduction electrocatalysts to generate a variety of valuable products.

Controlling the orientation of the transition dipole moment (TDM) is very important in the field of optoelectronics. In particular, the horizontal orientation of emissive TDMs in organic materials has been extensively studied because it can improve the out-coupling efficiency of organic light-emitting diodes (OLEDs). Conversely, the vertical orientation of emissive TDMs remains virtually unexplored. Using angle-dependent photoluminescence measurements, we discovered that 9,10-bis(3,5-dimethoxyphenyl) anthracene (DMA) shows an extremely high vertical emissive TDM orientation (ΘV) of 82% in an evaporated neat film. To the best of our knowledge, this is the highest value reported so far for organic molecules. To investigate the origin of the high ΘV value, we conducted two-dimensional grazing-incidence wide-angle X-ray scattering measurements (2D GIWAXS) on a DMA film and observed distinct periodic peaks in the out-of-plane direction. By combination of these measurements with single-crystal X-ray diffraction analysis, the periodic peaks were identified as lamellar structures in which DMA molecules are stacked with their long molecular axes oriented vertically on a quartz substrate. Moreover, by virtue of the exceptionally high vertical TDM orientation, the DMA film exhibits highly polarized emission from the substrate edge. We also investigated the TDM orientation of other 9,10-diphenylanthracene derivatives and observed random or horizontal TDM orientations in all cases, which highlights the uniqueness of the vertical orientation of DMA.