Nanoscience News (<front>)

A multidirectional sliding ferroelectricity in γ-InSe with a tunable bulk photovoltaic effect due to the existence of multiple polarization states is reported. The multidirectional sliding ferroelectricity is predicted by the theoretical calculations and multiple domain walls are observed experimentally. The multidirectional sliding ferroelectric polarization paves the path to explore novel optoelectronic applications like real-time imaging and neuromorphic computing.

Through the stacking technique of 2D materials, the interfacial polarization can be switched by an interlayer sliding, known as sliding ferroelectricity, which is advantageous in ultra-thin thickness, high switching speed, and high fatigue resistance. However, uncovering the relationship between the sliding path and the polarization state in rhombohedral-stacked materials remains a challenge, which is the key to 2D sliding ferroelectricity. Here, layer-dependent multidirectional sliding ferroelectricity in rhombohedral-stacked InSe (γ-InSe) is reported via dual-frequency resonance tracking piezoresponse force microscopy and conductive atomic force microscopy. The graphene/γ-InSe/graphene tunneling device exhibits a tunable bulk photovoltaic effect with a photovoltaic current density of ≈15 mA cm−2 due to multiple polarization states. The generation of dome-like domain walls is observed experimentally, which is attributed to the multidirectional sliding-induced domains based on the theoretical calculations. Furthermore, the ferroelectric polarization in γ-InSe ensures that the tunneling device has a high photo responsivity of ≈255 A W−1 and a fast response time for real-time imaging. The work not only provides insights into the multidirectional sliding ferroelectricity of rhombohedral-stacked 2D materials but also highlights their potential for tunable photovoltaics and imaging applications.

A novel atomically dispersed catalyst (Co─Se/Co/NC) with the coexistence of Co single-atom sites and Co─Se dual-atom sites, exhibits outstanding ORR activity and stability. The introduction of Se single atoms and the synergistic effect of Co single-atom and Co─Se dual atom can modulate the d-band center of metal sites and promote the desorption of *OH, thereby significantly accelerating the ORR process.

Atomically dispersed transition metal (ADTM) catalysts are widely implemented in energy conversion reactions, while the similar properties of TMs make it difficult to continuously improve the activity of ADTMs via tuning the composition of metals. Introducing nonmetal sites into ADTMs may help to effectively modulate the electronic structure of metals and significantly improve the activity. However, it is difficult to achieve the co-existence of ADTMs with nonmetal atoms and clarify their synergistic effect on the catalytic mechanism. Therefore, elucidating the active sites within atomically dispersed metal-nonmetal materials and unveiling catalytic mechanism is highly important. Herein, a novel hybrid catalyst, with coexistence of Co single-atoms and Co─Se dual-atom sites (Co─Se/Co/NC), is successfully synthesized and exhibits remarkable performance for oxygen reduction reaction (ORR). Theoretical results demonstrate that the Se sites can effectively modulate the charge redistribution at Co active sites. Furthermore, the synergistic effect between Co single-atom sites and Co─Se dual-atom sites can further adjust the d-band center, optimize the adsorption/desorption behavior of intermediates, and finally accelerate the ORR kinetics. This work has clearly clarified the reaction mechanism and shows the great potential of atomically dispersed metal-nonmetal nanomaterials for energy conversion and storage applications.

Developing sufficiently effective bifunctional electrodes for low-voltage hydrogen production at industrial-grade current density is highly significant but challenging. This work innovatively engineers high-entropy alloy nanoflower array electrodes with abundant high-activity sites and optimizable reaction pathways, and achieves unprecedented performance for two-electrode hydrazine oxidation-assisted hydrogen production at industrial-grade current densities.

Developing sufficiently effective non-precious metal catalysts for large-current-density hydrogen production is highly significant but challenging, especially in low-voltage hydrogen production systems. Here, we innovatively report high-entropy alloy nanoflower array (HEANFA) electrodes with optimizable reaction pathways for hydrazine oxidation-assisted hydrogen production at industrial-grade current densities. Atomic-resolution structural analyses confirm the single-phase solid-solution structure of HEANFA. The HEANFA electrodes exhibit the top-level electrocatalytic performance for both the alkaline hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR). Furthermore, the hydrazine oxidation-assisted splitting (OHzS) system assembled with HEANFA as both anode and cathode exhibits a record-breaking performance for hydrogen production. It achieves ultralow working voltages of 0.003, 0.081, 0.260, 0.376, and 0.646 V for current densities of 10, 100, 500, 1 000, and 2 000 mA cm−2, respectively, and remarkable stability for 300 h, significantly outperforming those of previously reported OHzS systems and other chemicals-assisted hydrogen production systems. Theoretical calculations reveal that extraordinary performance of HEANFA for OHzS is attributed to its abundant high-activity sites and optimizable reaction pathways in HER and HzOR. In particular, HEANFA enables intelligent migration of key intermediates during HzOR, thereby optimizing the reaction pathways and creating high-activity sites, ultimately endowing the extraordinary performance for OHzS.

Cryoprotectants in biological buffer systems often struggle due to the presence of abundant salts. A precise topological control of polyglycerols provides unique retention-and-release of sodium ions, which activates the formation of hydrogen bonding with ice interfaces. This interaction allows the polymer to inhibit ice growths both in intra- and extracellular spaces, resulting in successful post-thaw cell survival and network-forming functionality.

In this study, a novel phenomenon is identified where precise control of topology and generation of polyglycerol induce the retention of Na+ ions in biological buffer systems, effectively inhibiting ice crystal growth during cryopreservation. Unlike linear and hyperbranched counterparts, densely-packed hydroxyl and ether groups in 4th-generation dendritic polyglycerol interact with the ions, activating the formation of hydrogen bonding at the ice interface. By inhibiting both intra- and extracellular ice growth and recrystallization, this biocompatible dendritic polyglycerol proves highly effective as a cryoprotectant; hence, achieving the cell recovery rates of ≈134–147%, relative to those of 10% dimethyl sulfoxide, which is a conventional cryoprotectant for human tongue squamous carcinoma (HSC-3) cell line and human umbilical vein endothelial (HUVEC) cells. Further, it successfully recovers the network-forming capabilities of HUVEC cells to ≈89% in tube formation after thawing. The Na+ ion retention-driven ice-growth inhibition activity in biological media highlights the unique properties of dendritic polyglycerol and introduces a new topological concept for cell-cryoprotectant development.

A bicontinuous mesoporous carbon nanofiber and carbon nanosheet network is developed to enable high site utilization of single-atom Ni and interfacial CO2 enrichment. The in situ dynamic transformation of the planar Ni−N4 to an out-of-plane configuration is revealed, showing enhanced intrinsic electrokinetics for CO2 reduction. The integrated merits of network support and in situ tailored low-valance-state Ni site endow outstanding performance in acidic CO2-to-CO electrolysis.

Carbon-supported single-atom catalysts exhibit exceptional properties in acidic CO2 reduction. However, traditional carbon supports fall short in building high-site-utilization and CO2-rich interfacial environments, and the structural evolution of single-atom metals and catalytic mechanisms under realistic conditions remain ambiguous. Herein, an interconnected mesoporous carbon nanofiber and carbon nanosheet network (IPCF@CS) is reported, derived from microphase-separated block copolymer, to improve catalytic efficiency of isolated Ni. In IPCF@CS nanostructure, highly mesoporous IPCF hinders stacking of CS that provides additional fully exposed sites and abundant bicontinuous mesochannels of IPCF facilitate smooth CO2 transport. Such unique features enable enhanced Ni utilization and local CO2 enrichment, which cannot be achieved over conventional pore-deficient and discontinuous porous carbon fibers-based supports. In situ X-ray and Infrared spectroscopy coupling constant-potential calculations reveal the dynamic distortion of the planar Ni−N4 to an out-of-plane configuration with expanded Ni−N bond during operating CO2 electroreduction. The potential-driven low-valance-state Ni−N4 possesses enhanced intrinsic electrokinetics for CO2 activation and CO desorption yet inhibiting hydrogen evolution. The favorable electronic and interfacial reaction environments, resulted from the in situ tailored Ni site and IPCF@CS support, achieve an FE of near 100% at 540 mA cm−2, a TOF of 55.5 s−1, and a SPCE of 89.2% in acidic CO2-to-CO electrolysis.

This work proposes a universal synthesis method for rare-earth single-atom catalysts with Cl axially coordination for oxygen reduction reaction (ORR), which exhibits excellent ORR activity and successful applications in zinc-air batteries. The strong d-p orbital coupling between La and Cl significantly improves the electronic structure of the La site, ensuring efficient activation of O2 and suitable adsorption of *OH.

Currently, there are still obstacles to rationally designing the ligand fields to activate rare-earth (RE) elements with satisfactory intrinsic electrocatalytic reactivity. Herein, axial coordination strategies and nanostructure design are applied for the construction of La single atoms (La-Cl SAs/NHPC) with satisfactory oxygen reduction reaction (ORR) activity. The nontrivial LaN4Cl2 motifs configuration and the hierarchical porous carbon substrate that facilitates maximized metal atom utilization ensure high half-wave potential (0.91 V) and significant robustness in alkaline media. The aqueous and flexible Zinc-air battery (ZAB) integrating La-Cl SAs/NHPC as the cathode catalyst exhibits a maximum power density of 260.7 and 68.5 mW cm−2, representing one of the most impressive RE-based ORR electrocatalysts to date. Theoretical calculations have demonstrated that the Cl coordination evidently modulate the electronic structures of La sites, which promoted electron transfer efficiency by d-p orbital couplings. With enhanced electroactivity of La sites, the adsorptions of key intermediates are optimized to alleviate the energy barriers of the potential-determining step. Importantly, this preparation strategy is also successfully applied to other REs. This work provides perspectives for near-range electronic structure modulation of RE-SAs based on a nonplanar coordination micro-environment for efficient electrocatalysis.

Zn1.2Ga1.6Ge0.2O4:Ni2+ nanophosphor with NIR II emission that is responsive to environmental stimuli including temperature and specific solvent variations has been successfully prepared. Leveraging the unique properties of ZGGO:Ni NIR II nanophosphors, an innovative environment-interactive information encryption strategy with multiple dimensions, including wavelength, luminescence lifetime, and external stimuli like temperature and humidity has been developed to enhance information security.

Inspired by the natural responsive phenomena, herein the multiple responsive persistent luminescent Zn1.2Ga1.6Ge0.2O4:Ni2+ (ZGGO:Ni) nanoparticles with near-infrared  (NIR) II emission peak ≈1330 nm derived from the Ni2+ doping through controlled synthesis based on hydrothermal method are obtained. The obtained NIR II persistent luminescent ZGGO:Ni can not only respond to temperature but also the specific solvent stimulus. The results demonstrate that the NIR II persistent luminescence intensity decreases in hydroxyl containing solvent such as water (H2O) and ethyl alcohol (C2H6O), while the PL intensity remains in solvent without hydroxyl groups such as n-hexane (C6H14) and deuterated water (D2O). This NIR II luminescence quenching is attributed to the adsorption of interaction hydroxyl groups in specific solvents with the amino group on the surface of ZGGO:Ni and the subsequent fluorescence resonance energy transfer mechanism. Benefiting from the multiple responsive properties, the obtained NIR II persistent luminescent ZGGO:Ni is utilized for high-order dynamic optical information encryption, providing increased security level. The multi-responsive NIR II persistent luminescence strategy outlined in this study is anticipated to offer a straightforward methodology for optimizing the optical characteristics of NIR II persistent luminescent materials. Moreover, it is set to expand the scope of their applications in the realm of dynamic and environment-interactive information encryption, thereby opening frontiers for their utilization in advanced security measures.

The as-prepared Cu-ZnS exhibits excellent performance in the selective photoreduction of CO₂ to CH₃CH₂COOH, achieving a production rate of 0.45 µmol h−¹, which increases to 16.9 µmol h−¹ with triethanolamine while maintaining a high product selectivity of 97%. Using in situ experimental techniques and theoretical calculations, the key C₃ intermediates are identified providing crucial insights into the CH₃CH₂COOH formation pathway.

The direct photocatalytic conversion of CO2 and H2O into high-value C3 chemicals holds great promise but remains challenging due to the intrinsic difficulty of C1–C1 and C2–C1 coupling processes and the lack of clarity regarding the underlying reaction mechanisms. Here, the design and synthesis of a Cu-ZnS photocatalyst featuring dispersed Cu single atoms are reported. These Cu single atoms are coordinated with S atoms, forming unique Cu-S-Zn active units with tunable charge distributions that interact favorably with surface-adsorbed intermediates. This configuration stabilizes the *COHCO intermediate and facilitates its subsequent coupling with *CO to form *COCOHCO both thermodynamically and kinetically favorable on the Cu-ZnS surface. Notably, multiple critical C3 intermediates, including *COCOHCO, *OCCCO, and *CHCHCO, are identified, providing a clear reaction pathway for CO2 to CH3CH2COOH conversion. The Cu-ZnS photocatalyst achieves a CO2 to CH3CH2COOH conversion rate of 0.45 µmol h−¹ with an electron selectivity of 91.2%. Remarkably, in the presence of triethanolamine, the production rate increases to 16.9 µmol h−¹ with a selectivity of 99.8%. These findings underscore the importance of modulating multicarbon coupling processes to enable the efficient photocatalytic transformation of CO2 into C3 products, paving the way for future advancements in sustainable chemical synthesis.

A universal phase-engineering strategy is reported to achieve mechanically robust hydrogels by tuning microphase separation using cellulose nanocrystal (CNC) and common compatible polymer systems. CNC plays a crucial role in contributing to mitigating microphase separation for strengthening and toughening hydrogels. Benefiting from the CNC-mitigated microphase separation structure, the enabling hydrogel exhibits unprecedented combinations in mechanical properties.

As a common natural phenomenon, phase separation is exploited for the development of high-performance hydrogels. Using supersaturated salt to create microphase-separated hydrogels with strengthened mechanical properties has gained widespread attention. However, such strengthened hydrogel loses its intrinsic flexibility, making the phase separation strategy unsuitable for the fabrication of stretchable and tough hydrogels. Here, a phase-engineering design strategy is introduced to produce stretchable yet tough hydrogels using supersaturated NaAc salt, by leveraging the hydration effect of cellulose nanocrystal (CNC) to mitigate microphase separation. The CNC-mitigated microphase-separated hydrogel presents unprecedented mechanical properties, for example, tensile strength of 1.8 MPa with a fracture strain of 4730%, toughness of 43.1 MJ m−3, fracture energy of 75.4 kJ m−2, and fatigue threshold up to 3884.7 J m−2. Furthermore, this approach is universal in synthesizing various microphase separation-enhanced polymer gels, including polyacrylic acid, poly(acrylic acid-co-acrylamide), gelatin, and alginate. These advancements provide insights into the incorporation of CNC-mediated microphase separation structures in hydrogels, which will foster the future development of high-performance soft materials.

This paper investigates the influence of thickness on the properties of thin epitaxial Bi films. It discusses results from optical, vibrational, and structural analyses, highlighting notable changes in dielectric function, phonon frequencies, and Peierls distortion. The competition between electron localization and delocalization is emphasized, showing how thickness reduction can tailor material properties without changing stoichiometry.

A systematic study of the impact of film thickness on the properties of thin Bi films is presented. To this end, epitaxial films of high quality have been grown on a Si (111) substrate with thicknesses ranging from 1.9 to 29.9 nm. Broadband optical spectroscopy reveals a notable decline in the optical dielectric constant and the absorption peak height as the film thickness decreases, alongside a shift of the absorption maximum to higher photon energies. Raman and pump-probe spectroscopy show that the phonon mode frequencies increase upon decreasing film thickness, with the in-plane mode frequency rising by 10% from the thickest to the thinnest sample. The X-ray diffraction analysis reveals an increasing Peierls distortion for thinner films, explaining the observed property changes. Quantum chemical bonding analysis and density functional theory calculations show that the properties of thin bismuth are influenced by the interplay between electron localization and delocalization, characteristic of metavalently bonded solids. This study shows that for solids that utilize metavalent bonding, a thickness reduction leads to significant property changes. The effect can even be employed to tailor material properties without the need to change material stoichiometry.

Machine learning has been successfully employed to optimize the compositions of multicomponent electrolytes. As a result, the as-obtained novel Zn-air batteries can deliver superior battery reversibility and stability (1700 h at 2 mA cm−2 and 1400 h at 20 mA cm−2), and greatly improved round-trip efficiency as high as 76.3%.

Aqueous alkaline Zn-air batteries (ZABs) have garnered widespread attention due to their high energy density and safety, however, the poor electrochemical reversibility of Zn and low battery round-trip efficiency strongly limit their further development. The manipulation of an intricate microscopic balance among anode/electrolyte/cathode, to enhance the performance of ZABs, critically relies on the formula of electrolytes. Herein, the Bayesian optimization approach is employed to achieve the effective design of optimal compositions of multicomponent electrolytes, resulting in the remarkable enhancement of ZAB performance. Notably, ethylene glycol has been successfully employed as both electrolyte additive and fuel, playing key roles in changing the reaction pathways of ZABs, especially the storage form of discharge products from ZnO deposition on the anode to Zn2+-based hybrid particle colloids in the electrolyte. As a result, the as-obtained novel ZABs can deliver superior battery reversibility and stability (1700 h at 2 mA cm−2 and 1400 h at 20 mA cm−2), greatly improved round-trip efficiency as high as 76.3%, and even continuous discharge until complete Zn anode depletion. This work has demonstrated enormous potential for long-term energy storage applications and holds promise for bringing new opportunities to the development of ZABs.

An ultra-stiff yet super-elastic aerogel is realized through the design of a topological cellular hierarchy, enabling it to support high loads through preferably reversible buckling deformation, thereby overcoming the intrinsic conflict between high stiffness and superior recoverability.

Lightweight cellular materials with high stiffness and excellent recoverability are critically important in structural engineering applications, but the intrinsic conflict between these two properties presents a significant challenge. Here, a topological cellular hierarchy is presented, designed to fabricate ultra-stiff (>10 MPa modulus) yet super-elastic (>90% recoverable strain) graphene aerogels. This topological cellular hierarchy, composed of massive corrugated pores and nanowalls, is designed to carry high loads through predominantly reversible buckling within the honeycomb framework. The compressive modulus of the as-prepared graphene aerogel is nearly twice that of conventional graphene aerogel. This high-stiff graphene aerogel also exhibits exceptional mechanical recoverability, achieving up to 60% strain recovery over 10 000 fatigue cycles without significant structural failure, outperforming most previously reported porous lattices and monoliths. It is further demonstrated that this graphene aerogel exhibits superior energy dissipation and anti-fatigue dynamic impact properties, with an energy absorption capacity nearly an order of magnitude greater than that of conventional aerogels. These exceptional properties of the topological cellular graphene aerogel open new avenues for high-energy bullet protection, offering great promise for the development of lightweight, armor-like protective materials in transportation and aerospace applications.

Concurrent superconductivity and negative photoconductivity (NPC) are discovered in PbSe0.5Te0.5 accompanying pressure-induced phase transitions. Both have a strong structure dependence and are jointly mediated by electron-phonon interplay, which is switchable via illumination or cooling at high-pressure. New findings offer more new insights into understanding the essence of photoelectric-lattice coupling and developing versatile materials of lead chalcogenides.

Concurrent superconductivity and negative photoconductivity (NPC) are rarely observed. Here, the discovery in PbSe0.5Te0.5 of superconductivity and photoconductivity transitions between positive photoconductivity (PPC) and NPC during compression is reported to ≈40 GPa and subsequent decompression, which are also accompanied by reversible structure transitions (3D Fm3¯${{\bar{3}}}$m ⇌ 2D Pnma ⇌ 3D Pm3¯${{\bar{3}}}$m). Superconductivity with a maximum T c of ≈6.7 K coincides with NPC and structure transition of Pnma to Pm3¯${{\bar{3}}}$m at ≈18 GPa and the latter phase is preserved down to ≈5 GPa with enhanced T c of ≈6.9 K during decompression. The observations imply the simultaneous superconducting and photoconductive transitions are closely related to the metallic Pm3¯${{\bar{3}}}$m phase. First-principles calculations suggest the enhanced p-p hybridization and charge transfer between Pb-5p and ligand-p orbitals near the Fermi surface play key roles in electron-phonon interaction of mediating the Cooper pairs in PbSe0.5Te0.5. Hall coefficient measurements reveal that photothermal effect enhances electron-phonon interplay, which decreases carrier concentration and mobility and results in the reversal of PPC-NPC. Structure-dependent superconductivity and NPC are jointly mediated by electron-phonon interplay, which is tunable through illumination or cooling at high-pressure. The findings shed light on the origin of superconductive and photoconductive transitions in versatile materials of lead chalcogenides.

A “smart” n-type conjugated polymer with glycolated side chains that forms a more ordered assembly when electrochemically doped, is reported along with a newly synthesized p-type conjugated polymer. The n-type and p-type polymers complement each other perfectly to construct an organic complementary inverter, achieving a record voltage gain of 307 VV−1.

The charge transport of channel materials in n-type organic electrochemical transistors (OECTs) is greatly limited by the adverse effects of electrochemical doping, posing a long-standing puzzle for the community. Herein, an n-type conjugated polymer with glycolated side chains (n-PT3) is introduced. This polymer can adapt to electrochemical doping and create more organized nanostructures, mitigating the adverse effects of electrochemical doping. This unique characteristic gives n-PT3 excellent charge transport in the doped state and reversible ion storage, making it highly suitable as an n-type organic mixed ionic-electronic conducting (OMIEC) material. n-PT3 exhibits a high electron mobility of µ ≈ 1.0 cm2 V−1 s−1 and a figure of merit value of µC* ≈ 100 F cm−1 V−1 s−1, representing one of the best results for n-type OMIEC materials. A new p-type OMIEC polymer has been synthesized as the channel material for constructing a complementary inverter to match the n-type OECT channel layer based on n-PT3. As a result, a voltage gain value of up to 307 VV−1 has been achieved, which is a record value for sub−1 V complementary inverters based on OECTs. This work offers valuable insights into designing electrochemical doping adaptive n-type OMIEC materials and fabricating high-gain organic complementary inverters.

A class of metasurfaces capable of multiplexing guided and space waves is proposed to achieve advanced EM functionalities in microwave regions, which can find great application potentials in radar systems, wireless communications, and wireless power transfer. The findings significantly expand the capabilities of metasurfaces in manipulating EM waves and stimulate advanced multifunctional meta devices facing more challenging and diversified application demands.

Nowadays, metasurfaces have attracted considerable attention due to their promising and advanced control of electromagnetic (EM) waves. However, it is still challenging to shape guided waves into desired free-space mode, while simultaneously manipulating spatial incident waves using a single metasurface. Herein, a class of metasurfaces capable of multiplexing guided and space waves is proposed to achieve advanced EM functionalities in microwave regions, which can find great application potentials in radar systems, wireless communications, and wireless power transfer (WPT). The proposed metasurface, composed of specially designed meta-atoms with polarization-dependent radiation and reflection properties, provides the capability to fully manipulate complex amplitude of guided waves and reflection phase of space incident wave independently and simultaneously, thus enabling arbitrary radiation and reflection functionalities without encountering crosstalk issues. As examples of potential applications, three advanced EM functionalities operating in both far-field and near-field regions are presented: low-sidelobe microwave antenna with reduced radar cross section (RCS), multifunctional WPT, and feed multiplexed holograms, respectively. The far-field characteristics of the low sidelobe level antennas showing radiated beams at ± 30° together with RCS reduction under arbitrarily polarized incidences are validated by both simulations and measurements. A good agreement between experiments and simulations is also observed for the near-field intensity distribution of the hologram, which further validates the feasibility of near-field shaping. The findings significantly expand the capabilities of metasurfaces in manipulating EM waves and stimulate advanced multifunctional metadevices facing more challenging and diversified application demands.

The charge transfer resistance of Li–S using the modified separator is reduced. In addition, there is no corrosion and the lithium anode is dendrite-free. The ‘shuttle effect’ of polysulfides is greatly suppressed.

The “shuttle effect” and the unchecked growth of lithium dendrites during operation in lithium–sulfur (Li–S) batteries seriously impact their practical applications. Besides, the performances of Li–S batteries at high current densities and sulfur loadings hold the key to bridge the gap between laboratory research and practical applications. To address the above issues and facilitate the practical utilization of Li–S batteries, the commercial separator is modified with solid electrolyte (nanorod LiAlO2, LAO) and conductive carbon (Super P) to obtain a double coated separator (SPLAOMS). The SPLAOMS can physically barrier polysulfides and accelerate reaction kinetics. In addition, it enhances uniform lithium deposition, boosts ionic conductivity, and increases the utilization of active sulfur substances. The prepared Li–S batteries exhibit excellent cycling stability under harsh conditions (high sulfur loadings and high current densities) with an initial capacity of 733 mAh g−1 and a capacity attenuation of 0.03% per cycle at 5C in 500 cycle life. Under ultra-high sulfur loading (8.2 mg cm−2), the prepared battery maintains a satisfactory capacity of 800 mAh g−1 during cycling, demonstrating enormous commercial application potential. This study serves as a pivotal reference for the commercialization of high-performance Li–S batteries.

Ultra-thin, layered single crystal films of molecular semiconductor 2,9-dioctylnaphtho[2,3-b]naphtha[2′,3′:4,5]thieno[2,3-d]thiophene (C8-DNTT-C8) are studied using conductive atomic force microscopy (C-AFM), revealing changes in out-of-plane electrical current as a function of the number of molecular layers. A vertical transfer length method is devised, which enables to estimate the out-of-plane charge transport properties of an organic semiconductor at an unprecedented molecular length scale.

High contact resistance remains the primary obstacle that hinders further advancements of organic semiconductors (OSCs) in electronic circuits. While significant effort has been directed toward lowering the energy barrier at OSC/metal contact interfaces, approaches toward reducing another major contributor to overall contact resistance – the bulk resistance – have been limited to minimizing the thickness of OSC films. However, the out-of-plane conductivity of OSCs, a critical aspect of bulk resistance, has largely remained unaddressed. In this study, multi-layered 2D crystalline, solution-processed films of the high-mobility molecular semiconductor 2,9-dioctylnaphtho[2,3-b] naphtha[2′,3′:4,5]thieno[2,3-d]thiophene (C8-DNTT-C8) are investigated using conductive-probe atomic force microscopy (C-AFM) to evaluate out-of-plane charge transport. The findings reveal a linear increase in out-of-plane resistance with the number of molecular layers in the film, which is modeled using an equivalent circuit model with multiple tunneling barriers connected in series. Building upon these results, a vertical transfer length method (V-TLM) is developed, allowing one to determine the out-of-plane resistivity of OSC and providing insights into charge transport properties at a single molecule length scale. The V-TLM approach highlights the potential of C-AFM for investigating out-of-plane charge transport in OSC thin films and holds promise for accelerating the screening of molecules for high-performance electronic devices.

The stabilization of Fe species is achieved through the chelation of asymmetric aldehyde-containing ligand THB, which enhances OER performance of NiFeOOH/THB in long-lasting overall water splitting by suppressing the dissolution of Fe and facilitating the rapid formation of highly valent active Fe (III) species.

Nickel-iron layered double hydroxides (NiFe LDHs) are considered as promising substitutes for precious metals in oxygen evolution reaction (OER). However, most of the reported NiFe LDHs suffer from poor long-term stability because of the Fe loss during OER resulting in severe inactivation. Herein, a dynamically stable chelating interface through in situ transformation of asymmetric aldehyde-ligand (THB, 1,3,5-Tris(3′-hydroxy-4′-formylphenyl)-benzene) modified NiFe LDHs to anchor Fe and significantly enhance the OER stability is reported. The fabricated asymmetric aldehyde-containing ligand THB is capable of stimulating much more interfacial charge transfer from NiFe LDHs to the oxygen group of THB and accelerating the formation of highly valent active Fe species leading to the strong combination between Fe and ligand and the reduced activation energy barrier of the intermediate, respectively. The optimized aldehyde-ligand-chelated NiFe LDHs (NiFe LDH/THB) shows enhanced OER performance featuring an overpotential of 224 mV at 100 mA cm−2 and robust stability for over 3860 h at 100 mA cm−2 in a water splitting device maintaining a cell voltage of only 1.68 V, which paves a new avenue to improve the water electrolysis performance of non-noble metal catalysts.

The selectivity of the sensing material can be expressed through the idiosyncratic behavior of the gas sensing process, meanwhile, the identification of the target gas becomes more accurate.

Traditional selectivity of gas sensors determined by the magnitude of the response value has significant limitations. The distinctive inversion sensing behavior not only defies the traditional sensing theory but also provides insight into defining selectivity. Herein, the novel definition of selectivity is established in a study with VO2(M1). The sensing behavior of VO2(M1) is investigated after its synthesis conditions optimization by machine learning. In gases of the same nature, VO2(M1) shows remarkably selective for NH3 marked with unique resistance increase behavior. Such anomalous behavior is attributed to the formation of the Schottky junction between VO2(M1) and the electrode. The “work function-electron affinity” relation is summarized as the selectivity coefficient, a parameter for predicting the selectivity of the sensing material effectively.

The precise bromination of the quinoxaline-fused core affords two isomeric nonfullerene acceptors, contributing to improved electronic and aggregation structures. AQx-22-based devices exhibit a superior PCE of 19.5% with a high open-circuit voltage of 0.97 V and the lowest energy loss of 0.476 eV reported to date for binary OSCs. Such an isomerization strategy shows great promise for developing next-generation high-performance OSCs.

Highly efficient nonfullerene acceptors (NFAs) for organic solar cells (OSCs) with low energy loss (E loss) and favorable morphology are critical for breaking the efficiency bottleneck and achieving commercial applications of OSCs. In this work, quinoxaline-based NFAs are designed and synthesized using a synergistic isomerization and bromination approach. The π-expanded quinoxaline-fused core exhibits different bromination sites for isomeric NFAs, namely AQx-21 and AQx-22. Theoretical and experimental analyses reveal that the isomerization effect of core bromination significantly influences molecular intrinsic properties, including electrostatic potentials, polarizability, dielectric constant, exciton binding energy, crystallinity, and miscibility with donor materials, thereby improving molecular packing and bulk-heterojunction morphology. Consequently, the AQx-22-based blend exhibits enhanced crystallinity, reduced domain size, and optimized phase distribution, which facilitates charge transport, suppresses charge recombination, and improves charge extraction. The AQx-22-treated OSCs obtain an impressive efficiency of 19.5% with a remarkable open-circuit voltage of 0.970 V and a low E loss of 0.476 eV. This study provides deep insights into NFA design and elucidates the potential working mechanisms for optimizing morphology and device performance through isomerization engineering of core bromination, highlighting its significance in advancing OSC technology.