Browse Articles

Beyond the gradient expansion approximation: A generalized gradient expansion for exchange

The gradient expansion approximation (GEA) exchange in density functional theory is derived from the long-wavelength response of jellium and yields an analytic expansion in even powers of the reduced density gradient s. This structure reflects the perturbative q→0 limit rather than an exact constraint. Relaxing analyticity in s leads naturally to a generalized gradient expansion (GGE) based on a Puiseux series containing both integer and fractional powers. The exchange-hole structure of inhomogeneous jellium indicates that finite-wavevector singularities associated with the Kohn-anomaly at the Fermi surface generate non-analytic contributions, including a leading s3/2 behavior. Non-analytic, non-polynomial, and mixed structures are already intrinsic to widely used generalized gradient approximation (GGA) exchange functionals. With natural extensions to correlation, the GGE provides a minimal and rigorous extension of the GEA, enabling systematic construction of new GGA exchange–correlation functionals.

Supramolecular Cage‐Based Heterojunction: Chloroplast Mimicked Artificial Photosynthesis for Efficient Ethanol Production

ABSTRACT Photosynthesis of C 2+ products like ethanol through artificial photosynthetic overall reaction is much desired yet generally challenged by spatial confinement/utilization of C 1 intermediates or kinetically sluggish C─C bond coupling in the complex multi‐electronic reduction processes. Inspired by nature, a supramolecular biomimetic heterojunction (Zn‐TIPP/CdS) photocatalyst was designed by mimicking chloroplasts. The coupling of the unique supramolecular cage structure of Zn‐TIPP with CdS in this heterojunction successfully simulates the comprehensive functions of stroma and grana in chloroplasts, achieving one of the highest ethanol production rates (138.9 µmol g −1 h −1 , 93% selectivity) via artificial photosynthesis, which significantly surpasses most previously documented photocatalysts. Driven by the fast charge transfer efficiency in the biomimetic heterojunction, the spatial confinement and multisite catalytic effects of the supramolecular cage in Zn‐TIPP enable the cascade conversion of CO 2 into ethanol as revealed by in situ characterizations and theoretical calculations. The establishment of such redox heterojunction would promote the design of efficient photocatalysts for the generation of value‐added fuels through artificial photosynthetic overall reaction.

Kinetic theory of chiral active disks: Odd transport and torque density

Parity-odd transport is a central signature of chiral fluids, yet analytical predictions are sparse. Here, we introduce a minimal two-dimensional hard-disk gas in which chirality arises solely from a collision-induced transverse impulse. Motivated by granular spinners, collisions are dissipative and inject orbital angular momentum through a fixed tangential “kick” at contact. Starting from a Boltzmann–Enskog description, we derive nonlinear hydrodynamic equations for density, momentum, and temperature and show that chirality generates an antisymmetric homogeneous stress corresponding to a nonzero torque density. In the dilute limit, a Chapman–Enskog expansion yields analytical predictions for transport coefficients, including odd viscosity, odd thermal conductivity, and odd self-diffusivity, in good agreement with numerical simulations. This minimal kinetic model can serve as a foundation for systematic coarse-graining of chiral fluids and as a tractable benchmark for gaining insight into odd transport across a broader class of chiral systems.

Activation of Allylic Primary Alcohols With Biaryl Oxazepine Reagent for Chiral Phosphoric Acid‐Catalyzed Asymmetric S _N 1 Reaction

ABSTRACT Carbocations have long been important reactive intermediates in organic synthesis. Nevertheless, their inherent instability and high reactivity present formidable challenges to achieving precise stereocontrol. Previous strategies require the chiral catalyst to establish an optimal chiral environment around the carbocations, thus, high enantioselectivity can be obtained in these S N 1 reactions. Herein, we report a chiral phosphoric acid (CPA)‐catalyzed S N 1 reaction of primary allylic alcohol, in which the leaving group can modulate the reactivity and control enantioselectivity by forming a complex with the chiral catalyst. The key to the success of this reaction is the development of an alcohol activation reagent (biaryl oxazepine), which can chemoselectively activate allylic alcohol to form an intermediate with good leaving ability. A series of allylic 5,6‐dihydrophenanthridine and 6 H ‐benzo[ c ]chromene products could be obtained in high yields with excellent enantioselectivities. Further transformations and applications of the resulting 5,6‐dihydrophenanthridine derivatives and the asymmetric formal total synthesis of several natural products demonstrated the utilities of this reaction. Mechanistic studies support that the reaction proceeds via an S N 1 pathway, in which the enantio‐control of allyl carbocations was achieved by in situ formed complex from chiral catalysts and leaving groups.

Erratum: “Electronic-state-resolved master equation study of energy transfer and electron-impact chemical kinetics in the nitrogen system” [J. Chem. Phys. 164, 134310 (2026)]

Thermally Activated “Cold” Holes Overcome Recombination Limits in Single‐Component Organic Solar Cells With 15.6% Efficiency

ABSTRACT Single‐component organic solar cells (SCOSCs) based on double‐cable conjugated polymers offer unparalleled morphological stability compared to bulk‐heterojunction systems, but their efficiencies are severely bottlenecked by rapid geminate recombination. While the intrinsic donor–acceptor proximity in these polymers generates ultralong‐lived charge‐transfer (CT) states (>5 ns), these “cold” carriers are traditionally viewed as an energetic trap. Here, we report a thermodynamic strategy that converts this extended temporal window into a resource for thermally activated charge extraction. By engineering an interfacial energy ladder using a D18 polymer layer with a precise 0.02 eV highest occupied molecular orbital (HOMO) offset, we demonstrate that long‐lived holes can be thermally promoted and selectively harvested. This active energy management mechanism successfully outcompetes non‐radiative recombination loss, simultaneously elevating the open‐circuit voltage, short‐circuit current, and fill factor. Consequently, the optimized devices achieve a record‐breaking power conversion efficiency of 15.65%. This work establishes a new paradigm for organic photovoltaics: demonstrating that long‐lived excited states, previously considered a fundamental limitation, can be strategically harnessed as a thermal activation reservoir to overcome thermodynamic recombination losses.

Interplay between capillary and dispersion forces in adhesion under ambient conditions

Measurements of adhesion force between hydrophilic rough surfaces performed at controlled humidity generated controversial results at humidity below the critical one. Measurements with adhered cantilever demonstrated roughness but not humidity dependence, while measurements with atomic force microscope (AFM) showed an important role of capillary interaction. In this paper, the controversy is resolved using the contact of a deposited Au surface with Si wafer as an example. No assumption on surface roughness is made. Instead, all necessary information is extracted from large, detailed AFM scans. Using the force balance equation, not only the adhesion force but also a realistic place-to-place variation of the force is determined. Critical new elements of the analysis are the inclusion of the long-distance dispersion force and the nominal area of contact. For small roughness, the short-distance, capillary, and long-distance dispersion forces are all proportional to the nominal area of contact as usually assumed. However, for larger roughness, the short-distance and capillary forces grow with area much slower, making the role of the dispersion force more important. An additional factor that influences the relative contribution of different forces to adhesion is the average distance at contact, which is also determined from the force balance. Very different nominal areas of contact used in the adhered cantilever and AFM measurements explain the seeming contradiction between these experiments.

Bio‐Inspired Zymogen‐Activation Strategy for On‐Demand and Bilateral Interphase Formation in Aqueous Zinc‐Ion Batteries

ABSTRACT Aqueous zinc‐ion batteries (AZIBs) possess distinct benefits in cost and safety, but bilateral interfacial failures on Zn anodes and MnO 2 cathodes constrain their practical applications. Inspired by zymogen‐to‐enzyme activation, this work proposes a biomimetic, intelligent electrolyte additive strategy that enables on‐demand protection on both electrodes. This strategy employs an inert additive, 1,4‐butane sultone (BS), which preferentially adsorbs on the electrode surfaces. Upon water attack and localized pH increase, BS can be activated, generating open‐ring derivatives (OBS) to facilitate the in situ construction of bilateral protective interphases with organic–inorganic composite components. Concurrently, it optimizes Zn 2+ solvation structures to lower the desolvation energy barrier. Residual BS further traps SO 4 2− and H 2 O and sustains the OBS formation for preventing interfacial alkalization. Consequently, the BS‐modified Zn//Zn cell delivers a lifespan exceeding 4000 h, and the Zn//Cu cell attains an ultrahigh initial Coulombic efficiency of 97.62%. Zn//MnO 2 full cells maintain capacity retention of 92.7% and 80.5% after 100 cycles at 0.2 A g −1 and 8000 cycles at 6 A g −1 , respectively. Such a strategy not only delivers a high‐performance electrolyte additive for AZIBs but also offers biomimetic inspiration for the development of electrolytes in other metal‐based battery systems.

Beyond Self‐Assembled Molecules: Hydrogen‐Bonding‐Regulated Crystallization of Wide‐Bandgap Perovskite for High‐Performance Perovskite‐Silicon Tandem Photovoltaics

ABSTRACT Wide‐bandgap (WBG) perovskites crystallization is essential for high‐efficiency perovskite–silicon tandem solar cells (TSCs), yet their fabrication on self‐assembled molecules (SAMs) is often challenged by solvent‐induced damage and uncontrolled packing. Here, we report an interfacial engineering strategy that goes beyond conventional SAM modification by introducing a thiophen‐3‐ylmethanamine hydrochloride (3‐TMA) molecular layer between the SAM and perovskite photo‐active layer. The aromatic thiophene units establish strong π ‑ π stacking interactions with the underlying SAM, forming a solvent‐resistant interlayer that stabilizes the anchored SAM structure during solution processing. Meanwhile, hydrogen‐bonding interactions between 3‐TMA and the perovskite precursors effectively decelerate crystallization, promoting uniform nucleation and high‐quality WBG perovskite films. The resulting interface exhibits improved energy‐level alignment and reduced interfacial stress, facilitating efficient charge transport and enhanced device stability. Consequently, single‐junction WBG perovskite devices with bandgaps of 1.67 and 1.84 eV achieve champion power conversion efficiencies (PCEs) of 23.17% and 19.61%, respectively. When integrated into monolithic perovskite‒silicon TSCs, the strategy enables PCEs of 33.21% (certified 32.13%) for rigid tandems and 31.03% (certified 30.34%) for flexible tandems. Encapsulated devices retain 92.3% of their initial performance after 1000 h of continuous 1 sun illumination at room temperature.

Machine‐Learning‐Guided Discovery of Boron‐Free Narrowband Blue Thermally Activated Delayed Fluorescence Emitters

ABSTRACT Thermally activated delayed fluorescence (TADF) emitters enable color‐pure, energy‐efficient organic light‐emitting diodes (OLEDs), yet many ultra‐narrowband designs rely on synthetically demanding boron incorporation. Here we discover boron‐free emitters that reconcile a robust nitrogen‐only polycyclic scaffold, Rec. 2020‐grade pure‐blue emission, and small singlet–triplet gaps (Δ E ST ) conducive to TADF. We enumerated 19 518 13‐ring carbazole‐containing polycyclic aromatic hydrocarbons (Cz‐PAHs) and obtained quantum‐chemical reference values for ∼1000 molecules: emission energies and Δ E ST at S 1 ‐optimized geometries. A graph neural network enabled library‐wide prediction and revealed a pronounced negative correlation between emission energy and Δ E ST ( R = −0.75), implicating configuration mixing in S 1 and indicating that small‐gap candidates are enriched in the pure‐blue regime. Two selected Cz‐PAH emitters were synthesized and display deep‐blue, exceptionally narrow photoluminescence (full widths at half maximum 17–19 nm) with small experimental Δ E ST (0.13–0.19 eV). OLEDs incorporating these emitters deliver narrowband blue electroluminescence ( λ EL 456 and 481 nm); device A reaches chromaticity coordinates of (0.139, 0.069), close to the Rec. 2020 blue primary, whereas the sensitized device D achieves a maximum external quantum efficiency of 35.2%. Collectively, this work expands the boron‐free TADF design space and establishes an experimentally validated route to discovering high‐color‐purity organic emitters.

Nickel‐Catalyzed Asymmetric Hydrophosphinamidation of Alkynes

ABSTRACT P ‐stereogenic phosphinamidates are highly pivotal structural motifs in drug discovery and the design of chiral ligands. Despite their utility, catalytic enantioselective access to these compounds remains a formidable challenge. Herein, we report the first nickel‐catalyzed asymmetric hydrophosphinamidation of alkynes. This protocol enables the highly efficient and enantioselective synthesis of structurally diverse alkenyl phosphinamidates, accommodating a wide array of both N, N ‐dialkyl and N ‐alkyl substituted H ‐phosphinamides. Notably, the resulting products exhibit orthogonal reactivities at four distinct sites, serving as a powerful and universal platform for the divergent synthesis of complex P ‐stereogenic architectures.

Intrinsic Near‐Infrared‐II Fluorescent Nanozymes Support High‐Resolution Imaging and Tumor Catalytic Immunotherapy

ABSTRACT Nanozymes hold considerable promise for in vivo therapy due to their stable and versatile enzyme‐mimicking activities. However, real‐time tracking of their dynamics with high spatiotemporal resolution and ensuring biosafety remain challenging. Here, we report a class of single‐component, metal‐free autofluorescent nanozymes (AFNZs) that simultaneously exhibit ultrabright second near‐infrared (NIR‐II) fluorescence (FL) and potent multienzyme‐like activities. By precisely controlling sulfur/nitrogen (S/N) stoichiometry during the solvothermal conversion of cyanine precursors, we developed intrinsically emissive nanozymes with high‐brightness NIR‐II FL (quantum yield >1.4%, maximum emission wavelength >1100 nm) among metal‐free nanozyme systems, achieving a 20‐fold enhancement over their precursors. The optimized AFNZs exhibit strong peroxidase (POD)‐, catalase (CAT)‐, and oxidase (OXD)‐like activities, enabling high‐contrast in vivo imaging and catalytic tumor therapy. Mechanistic studies suggest that the enhanced FL is associated with restricted intramolecular motion (RIM). These nanozymes support deep‐tissue tumor imaging (∼8 mm) and high‐resolution angiography (∼30 µm), substantially outperforming their precursors and the clinical contrast agent indocyanine green (ICG). Furthermore, they enable precise tumor margin identification, image‐guided resection of microtumors (< 5 mm), and real‐time monitoring of catalytic immunotherapy associated with autophagic flux disruption and immune activation. This work offers a stoichiometry‐guided strategy for constructing intrinsically fluorescent metal‐free AFNZs for image‐guided catalytic therapy.

Correction to “Nanoscale Metal–Organic Layers for Deeply Penetrating X‐ray‐Induced Photodynamic Therapy”

Reversible Click Reactions in Water: A Robust and Customizable Synthetic Tool

ABSTRACT Beyond the context of click chemistry, reversible click chemistry refers to a class of coupling reactions that satisfy all the characters of click reaction, besides offering well access for controllable decoupling process. Endowing click reaction with reversibility is extremely challenging due to the strong energy gain, which inhibits the path of disassociation. Herein, we report the reversible click reactions between highly customizable sulfur‐bridged N ‐aryl quinolinium derivatives and thiols in a closed‐loop approach, enabled by antagonistic nucleophilic addition toward aromatization. The click and declick process can be manipulated by employing base and acid, respectively, both featured with near‐unity efficiency, fast dynamics and stoichiometric dependence. Owing to excellent selectivity and robustness, this reversible click reaction can be well conducted in pure aqueous condition for the first time and achieve reversible protein modification. We anticipate that this work provides a novel methodology for green synthesis with high atom economy and biochemical modification in an erasable manner.

Charge‐Transfer Assembly of Electrically Conductive Metal–Organic Cages

ABSTRACT We report a strategy for utilizing metal–organic cages (MOCs) as building blocks for assembling porous materials with high electrical conductivity. Realizing conductivity in porous materials would unlock their potential in electrocatalytic and energy storage applications, but current materials with these properties are stymied by poor control over their physical form factors. The molecular nature of MOCs enables solution processability while also preserving permanent porosity, but the lack of formal bonds between discrete units has prevented the formation of conductive pathways. We show that by appending electron‐donating tetrathiafulvalene (TTF) groups to the surface of the MOC, and then reacting these cages with the molecular electron‐acceptor 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F 4 TCNQ), electrically conductive character can be introduced to reach conductivities on the order of 10 −6 S/cm. This conductivity is achieved without sacrificing the intrinsic porosity of the cage, as confirmed by gas and guest uptake experiments. Clear evidence of electron transfer between the appended donors and molecular acceptors creates a highly tunable charge‐transfer assembly motif and establishes MOCs as building blocks for targeting electrically conductive, porous materials.

Cu ⁺ ‐Cu ⁰ Cluster Pairs in Defective MOFs for Highly Synergistic CO ₂ Hydrogenation to Methanol

ABSTRACT Precise arrangement of multivalent Cu sites for the synchronized activation of CO 2 and H 2 in selective methanol synthesis remained challenging. Herein, we designed spatially arrayed Cu + ‐Cu 0 cluster pairs confined within UiO‐66 (U66) to achieve spatiotemporally directed CO 2 hydrogenation to methanol. This architecture was constructed by creating missing‐linker defects within U66 using L‐ascorbic acid (LA), followed by sequential anchoring of high‐density, adjacent Cu + ‐Cu 0 cluster pairs (≈1:1 ratio) to yield a Cu/U66(LA‐Cu) catalyst. Under reaction conditions of 220°C and 3 MPa, this catalyst achieved a methanol space‐time yield of 688.1 mg·g −1 ·h −1 and an ultra‐high methanol selectivity (97.0%). Its unity‐methanol selectivity was 1.06–1.77 times that of high‐stability oxide materials. Meanwhile, catalyst's stability of 200 h was significantly prolonged compared to high‐selectivity MOF‐based catalysts that operated stably for 60–175 h. Mechanistic studies revealed that Cu + ‐Cu 0 cluster pairs within defective U66 not only enabled partitioned synergistic activation of CO 2 and H 2 , but established an efficient electron/hydrogen transfer pathway. This facilitated the migration of active hydrogen species to CO 2 adsorption sites, where adsorbed CO 2 was converted into CO intermediates and underwent deep hydrogenation. This structural design synergistically enhanced compatibility between H 2 dissociation and CO 2 hydrogenation steps, enabling reaction to proceed efficiently along the RWGS + CO‐hydro pathway.

Substituent Variation in Tetraaza[14]Annulene‐Based Covalent Organic Frameworks for Modulation of Electronic States

ABSTRACT Introducing metal centers into covalent organic frameworks (COFs) is an effective and attractive strategy, but the pool of building blocks offering tunable structures and controllable electronic properties remains limited. Here, we designed two amino‐functionalized, tetrafunctional nickel tetraaza[14]annulene (TAA) building blocks and incorporated them into two‐dimensional COFs. Notably, the peripheral benzene rings of the TAA moiety bear abundant proximal sites amenable to modification, allowing facile tuning of the central nickel ion's electronic state. To investigate the positional effect of substituents, we constructed a pair of isomeric COFs containing the same number of fluorine atoms either at proximal or distal positions. Combined experimental and computational studies reveal that proximal fluorination more effectively reduces electron density at the nickel sites and enhances electron affinity, substantially improving electrocatalytic oxygen evolution reaction (OER) performance. Consequently, the optimized COF achieves an overpotential of 380 mV at 10 mA cm −2 , significantly outperforming its distal‐fluorine and fluorine‐free counterparts. This work establishes metal TAA macrocycles as a new class of building blocks for metal‐based COFs and demonstrates that precise substituent positioning is an effective strategy for modulating the electronic structure and catalytic performance of crystalline framework materials.

Carbon‐Encapsulated Gemini Ionic Liquid as Advanced Bromine Hosts for High‐Performance Zn–Br ₂ Batteries

ABSTRACT Zinc–bromine (Zn–Br 2 ) batteries represent a promising aqueous energy storage technology, yet their widespread deployment is hindered by the uncontrolled diffusion of molecular bromine from the cathode side, leading to severe self‐discharge and capacity fading. Here, we demonstrate an effective strategy to mitigate bromine crossover by employing gemini‐type bromine complexing agents (BCAs) impregnated into porous carbon hosts in their oily phase. This approach facilitates the in situ conversion of bromine into a water‐immiscible polybromide BCA phase, thereby confining the active species within the electrode structure. The presence of aromatic linkers in the gemini BCA molecules significantly enhance their retention in the carbon network, most likely through π – π stacking interactions with the carbon framework. Moreover, controlled discharge protocols enabled preferential nucleation of polybromide domains within the confined pore environment, further improving the self‐discharge stability of the system. As a result, the Zn–Br 2 cells incorporating gemini‐type BCAs exhibited suppressed bromine crossover, enhanced coulombic efficiency, and superior cycling durability compared to conventional systems. This work provides mechanistic insights and practical guidelines for the rational design of molecular complexants and electrode architectures for next‐generation Zn–Br 2 batteries.

Atomic–Level Interfacial Regulation Enables Efficient Chlorine Redox Chemistry in Rechargeable H ₂ ─Cl ₂ Batteries

ABSTRACT Hydrogen─chlorine (H 2 ─Cl 2 ) batteries are attractive high‐power energy storage systems but remain fundamentally limited by inefficient Cl 2 confinement and sluggish interfacial Cl 2 /Cl − redox kinetics. Here, we report a hydrogen‐bonded porphyrin framework with atomically dispersed Cu sites (SACu‐GTUB5) that enables efficient Cl 2 storage and accelerates Cl 2 /Cl − conversion. The intrinsic porosity of the framework combined with chemically active Cu─N 4 centers enables synergistic physical confinement and chemical adsorption of Cl 2 , effectively suppressing Cl 2 escape and improving Coulombic efficiency. As a result, the SACu‐GTUB5‐based H 2 ─Cl 2 battery exhibits stable operation across a wide temperature range (−40°C to 60°C) and achieves a high areal discharge capacity of 2.55 mAh cm −2 over 300 cycles. Spectroscopic analyses combined with density functional theory calculations reveal that Cu─N 4 sites govern Cl 2 adsorption, electron redistribution, and reaction pathways, substantially lowering the energy barriers for Cl 2 reduction. This work establishes an atomic‐level interfacial regulation strategy for controlling halogen redox chemistry in electrochemical energy storage.

Are Radiopharmaceutical Therapy Trials Designed to Undertreat?