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NanoManufacturing

Michael De Volder, Engineering Department - IfM
 
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Table of Contents for Advanced Materials. List of articles from both the latest and EarlyView issues.
Updated: 43 min 2 sec ago

Use of CsPbCl3 Quantum Dots as a Chlorine Source Enables Formation of Thick Quasi‐2D Perovskite Films for High‐Performance Blue Light Emitting Diodes

Tue, 01/07/2025 - 08:38

The use of organic-inorganic hybrid chlorine sources allows the preparation of thick perovskite films, leading to sky-blue light-emitting diodes (LEDs) with a record-high external quantum efficiency (EQE) of 26.2%.


Abstract

Achieving efficient and stable blue-emitting quasi-two-dimensional (quasi-2D) perovskite light-emitting diodes (LEDs) remains a challenge due to the poor solubility of conventional chloride precursors and the difficulty to form thick, uniform films with a well-controlled phase distribution. A new strategy is proposed to address this challenge using CsPbCl3 quantum dots (QDs) capped with oleylamine (OLA) ligands as an alternative chlorine source. It is demonstrated how the use of these QDs enables formation of quasi-2D perovskite films with vertically aligned crystalline structure, thickness over 100 nm, and improved stability. OLA ligands regulate the crystal phase distribution and grain boundaries, suppressing the appearance of small-n 2D phases and reducing the number of crystal defects, while inorganic CsPbCl3 QD cores induce vertical crystallization of quasi-2D perovskite films, endowing them with enhanced structural stability. The use of this non-conventional chlorine source is proven instrumental in improving external quantum efficiency of quasi-2D perovskite sky-blue LEDs, reaching 26.2% at 485 nm, with significantly enhanced electroluminescence stability both in terms of peak position and brightness. This study demonstrates a novel methodology using CsPbCl3 QDs capped with conventional organic ligands to achieve thick quasi-2D perovskite layers for blue LEDs, addressing existing limitations in perovskite optoelectronics.

Programmable Surface Dimpling of Textile Metamaterials for Aerodynamic Control

Tue, 01/07/2025 - 08:37

Static aerodynamic surfaces are inherently limited in their ability to adapt to dynamic velocity profiles or environmental changes, restricting their performance. Here, a stretched-induced auxetic dimpling textile that tunes surface roughness while tightly fitted is presented. Wind-tunnel tests and FE design mapping show controllable dimples can cut drag by up to 20% in target ranges, and real-time strain adjustments can sustain optimal performance of a cylindrical body


Abstract

Static aerodynamic surfaces are inherently limited in their ability to adapt to dynamic velocity profiles or environmental changes, restricting their performance under variable operating conditions. This challenge is particularly pronounced in high-speed competitive sports, such as cycling and downhill skiing, where the properties of a static textile surface are mismatched with highly dynamic wind-speed profiles. Here, an textile metamaterial is introduced that is capable of variable aerodynamic profiles through a stretch-induced dimpling mechanism, even when tightly conformed to a body or object. Wind-tunnel experiments are used to characterize the variable aerodynamic performance of the dimpling mechanism, while Finite Element (FE) simulations efficiently characterize the design space to identify optimal textile metamaterial architectures. By controlling dimple size, the aerodynamic performance of the textile can be tailored for specific wind-speed ranges, resulting in an ability to modulate drag force at target wind-speeds by up to 20%. Furthermore, the potential for active control of a textiles' aerodynamic properties is demonstrated, in which controlled stretching allows the textile to sustain optimal performance across a dynamic wind-speed profile. These findings establish a new approach to aerodynamic metamaterials, with surface dimpling and thus variable fluid-dynamic properties offering transformative applications for wearables, as well as broader opportunities for aerospace, maritime, and civil engineering systems.

Coexisting Non‐Trivial Van der Waals Magnetic Orders Enable Field‐Free Spin‐Orbit Torque Magnetization Dynamics

Tue, 01/07/2025 - 08:36

The coexistence of ferromagnetic and antiferromagnetic orders in van der Waals magnet above room temperature, inducing an intrinsic exchange bias and canted perpendicular magnetism is discovered. Such non-trivial intrinsic magnetic order enables the realization of energy-efficient and magnetic field-free spin-orbit torque memory devices.


Abstract

The discovery of van der Waals (vdW) magnetic materials exhibiting non-trivial and tunable magnetic interactions can lead to exotic magnetic states that are not readily attainable with conventional materials. Such vdW magnets can provide a unique platform for studying new magnetic phenomena and realizing magnetization dynamics for energy-efficient and non-volatile spintronic memory and computing technologies. Here, the coexistence of ferromagnetic and antiferromagnetic orders in vdW magnet (Co0.5Fe0.5)5-xGeTe2 (CFGT) above room temperature, inducing an intrinsic exchange bias and canted perpendicular magnetism is discovered. Such non-trivial intrinsic magnetic order enables to realize energy-efficient, magnetic field-free, and deterministic spin-orbit torque (SOT) switching of CFGT in heterostructure with Pt. These experiments, in conjunction with density functional theory and Monte Carlo simulations, demonstrate the coexistence of non-trivial magnetic orders in CFGT, which enables field-free SOT magnetization dynamics in spintronic devices.

Monolithic Terahertz Topological Mach‐Zehnder Interferometer

Tue, 01/07/2025 - 08:36

A monolithic topological Mach-Zehnder interferometer (MZI) is presented, integrating the splitter, combiner, and waveguide arms on a single chip. The interferometric fringes exhibiting high on-off contrast with extinction ratios over 20 dB are achieved by utilizing tailored unit cells that facilitate interface-dependent out-of-plane radiation losses. We also demonstrate active tuning of the MZI response through photoexcitation of the MZI arms.


Abstract

The pursuit of on-chip electromagnetic wave control for high throughput communication, spectroscopy, and quantum computing underlies the motivation for terahertz photonic integrated circuitry. Recent breakthroughs in topological photonics have enabled the development of chips that harness topologically resilient interface modes to achieve area and performance efficiency. However, the demonstration of a compact, monolithic topological Mach-Zehnder interferometer (MZI), remains a critical gap. In this work, a terahertz topological MZI is presented, exhibiting six interferometric fringes across a 17 GHz bandwidth, with splitter, combiner, and arms integrated on a single chip. The interferometric fringes exhibiting high on-off contrast with extinction ratios over 20 dB are achieved by utilizing tailored unit cells that facilitate interface-dependent out-of-plane radiation losses. Active tuning of the MZI response is also demonstrated through photoexcitation of the MZI arms. The presented approach is the first step toward realizing topological photonic modulators that leverage the phase degree of freedom for photonic integrated communication and quantum information processing.

Electrocatalytic and Photocatalytic C─N Coupling From Small Molecules

Tue, 01/07/2025 - 08:35

This review summarizes the recent electrocatalytic/photocatalytic synthesis of C–N coupling compounds (including urea, amide, and amino acids) from various carbonaceous species and various nitrogenous species, focusing on the designs of different catalytic sites and reaction mechanisms. The existing challenges and future research directions are also supplemented.


Abstract

Electrocatalytic/photocatalytic C─N coupling from small carboncontaining (such as CO2 and CH3OH) and nitrogen-containing species (such as N2, NO3 −, and NH3) enables the synthesis of value-added organonitrogen compounds, including urea, amides, and amino acids. This approach, ideally driven by renewable energy, holds great promise for sustainable developments and has thus been attracting increasing research interest in recent years. To enhance the C─N coupling under mild reaction conditions, it is necessary to activate different substrate molecules effectively and balance the adsorption and desorption of various C- and N-containing intermediates and/or radicals, thereby realizing different value-added organonitrogen compounds. In this review, the recent advances in electrocatalytic/photocatalytic C─N coupling reactions targeting those three types of products, i.e., urea, amides, and amino acids is aimed to summarized. The rational designs of active sites for synergistic catalysis are discussed, including their types, compositions, spatial arrangements, crystal facets, heterostructures, and local environments. Different reactant molecules and catalytic mechanisms for the electrocatalytic/photocatalytic C─N coupling reactions, as well as the methods of C─N coupling products detection, are also described. Finally, the existing challenges in this field are summarized, and the potential research perspectives are also proposed.

Surface‐Engineered Orthopedic Implant to Break the Antimicrobial‐Osteogenic Paradox at Biointerfaces in the “Race for the Surface”

Tue, 01/07/2025 - 08:18

Through polyphenol-amine-mediated covalent modification, quaternary ammonium groups (bactericidal agents) and phosphate groups (promoting bone-regeneration factors) are spatially organized on titanium (Ti) surfaces to regulate the surface chemical characteristics of dental implants. The surface-engineered implants (Ti-AQs) exhibited balanced antibacterial and biocompatible properties.


Abstract

Implant-associated infections and compromised osseointegration pose a dual threat to bone implants due to the biological conflict between microbial invasion and host cell colonization. However, conventional contact-killing antimicrobial coatings may negatively affect the viability of mammalian cells, limiting their further application. Here, a surface modification strategy is proposed to help mammalian cells to win the “race for the surface” on the material-tissue interfaces. Through polyphenol-amine-mediated covalent modification, quaternary ammonium groups (bactericidal agents) and phosphate groups (promoting bone-regeneration factors) are spatially organized on titanium (Ti) surfaces to regulate the surface chemical characteristics of dental implants. The surface-engineered implants (Ti-AQs) exhibited balanced antibacterial and biocompatible properties. The optimized Ti-AQ-2 coating eradicated >99% of Staphylococcus aureus ( S. aureus) and Escherichia coli ( E. coli) via destruction of disrupted bacterial membranes through metabolic interference, and simultaneously promoted adhesion, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells through Ca2+-mediated signaling pathways. Moreover, Ti-AQs can drive immunomodulation biased macrophages toward pro-repair M2 polarization. In vivo evaluations in an implant-associated infection modal confirmed that Ti-AQ-2 inhibited infection at the early stage and enhanced bone-implant integration at the late stage. This work presents a facile strategy to regulate the surface performances for developing of antibacterial implants with high biocompatibility and bioactivity.

Porous Elastomer Film with Controlled Liquid‐Metal Distribution for Recyclable Highly Customizable and Stretchable Patterned Electronics

Tue, 01/07/2025 - 08:12

This study presents a customizable porous liquid-metal (LM)/elastomer composite film with controlled LM distribution, overcoming conventional limitations of LM-based composites (unintended activation of unsintered regions under strain). It can achieve precise patterning through imprinting, thereby enabling the creation of flexible conductive patterns, which can be used in multifunctional stretchable electronics.


Abstract

Stretchable conductors with conductive patterns are crucial for flexible electronics, which demand high conductivity and stable electrical properties under significant deformations. Liquid-metal (LM)-based composites patterned by selective sintering are promising for flexible electronics, however, short-circuiting may occur due to unintended activation of unsintered regions under strain. Hence, developing highly customizable LM-based stretchable conductors remains a persistent challenge. Stretchable LM/thermoplastic polyurethane (TPU) porous films are designed with controlled LM distribution through non-solvent-induced phase separation and surface modification of LM particles, which overcomes the limitations of conventional LM-based stretchable composites and enables the design of diverse flexible electronics with conductive patterns via imprinting. The porous structure increases spacing between LM particles and alleviates stress on LM particles, ensuring electrical insulation of the unimprinted regions during stretching. The customizable patterning process enables the films to be used for electromagnetic interference (EMI) shielding, and stripe patterns allow for dynamic tuning of EMI shielding performance. Additionally, they demonstrate excellent performance in wireless communications, tunable EM wave filters, and stretchable Joule heaters. Moreover, the solubility of TPU makes it easy to recycle LM from the film, thus demonstrating ideal recyclability. Outstanding electrical stability and versatile applications guarantee its significant impact on stretchable electronics.

Efficient and Stable Topological/Ferroelectric Bi2Te3/SnSe Hetero‐Memristor for In Situ Bionic‐Visual Semi‐Hardware Systems

Tue, 01/07/2025 - 08:11

By combining the advantages of two-dimensional (2D)two-dimensional ferroelectrics and 2D topological insulators, the Bi2Te3/SnSe hetero-memristor is constructed to achieve ultra-high and stable optoelectronic sensing characteristics. The device shows an average 0.25 µW on/off power and 32 controllable conductive states. The semi-hardware neuromorphic system based on it achieved a 97.68% classification accuracy in low orbit satellite image recognition tasks.


Abstract

As the application of artificial vision systems continues to grow, developing efficient and low-power visual sensing devices has become a key challenge. Memristors offer tunable conductivity and integrated in-situ storage and computation functions, making them ideal for low-cost visual systems. However, most memristors currently face the dual challenges of poor stability and limited optoelectronic synaptic plasticity. Here, a Bi2Te2.7Se0.3/SnSe hetero-memristor is designed, which combines the advantages of two-dimensional (2D) topological insulators and 2D ferroelectric materials. The hetero-memristor performance can be tuned by the SnSe ferroelectric polarization and Bi2Te2.7Se0.3 topological surface state, which improve the utilization and mobility of carriers, thereby significantly improving the performance. The high 104-cycle stability, average 0.25 µW on/off power, and 25 conductive states are achieved. Under different signals, the hetero-memristor can enable in situ light-electric conversion and successfully simulate various optoelectronic plasticity behaviors, such as paired-pulse facilitation, post-tetanic potentiation, spike rate-dependent plasticity, etc. Mean while, an efficient in-situ bionic-visual semi-hardware system is constructed based on the 28 × 28 perception hetero-memristor array. This system efficiently performs satellite image recognition and classification, achieving an accuracy of 97.68%. The research shows that the Bi2Te2.7Se0.3/SnSe hetero-memristor is with excellent optoelectronic performances and broad application prospects, particularly in brain-like computing, smart hardware, and storage technologies.

Strain‐Induced Robust Skyrmion Lattice at Room Temperature in van der Waals Ferromagnet

Tue, 01/07/2025 - 08:10

This work demonstrates formation of robust ordered skyrmion lattices in pre-annealed 2D Fe3GaTe2 at room temperature via minimal strain. Magnetic force microscopy reveals that the stabilized skyrmion phase endures thousands of cycles of mechanical fatigue (stretching/bending/twisting), maintains stability across broad magnetic field and temperature ranges, and exhibits field-free stability. These results hold promise for flexible, low-power spintronic applications.


Abstract

Manipulating topological magnetic orders of 2D magnets by strain, once achieved, offers enormous potential for future low-power flexible spintronic applications. In this work, by placing Fe3GaTe2 (FGaT), a room-temperature 2D ferromagnet, on flexible substrate, a field-free and robust formation of skyrmion lattice induced by strain is demonstrated. By applying a minimal strain of ≈0.80% to pre-annealed FGaT flakes, the Magnetic Force Microscopy (MFM) tip directly triggers the transition from maze-like domains to an ordered skyrmion lattice while scanning the sample surface. The skyrmion lattice is rather stable against extensive cyclic mechanical testing (stretching, bending, and twisting over 2000 cycles each). It also exhibits stability across a wide range of magnetic fields (≈2.9 kOe) and temperatures (≈323 K), as well as long-term retention stability, highlighting its robustness and field-free stabilization. The strain effect reduces the lattice symmetry and enhances the Dzyaloshinskii-Moriya interaction (DMI) of FGaT, thus stabilizing the skyrmion lattice. The findings highlight the potential of FGaT for integrating magnetic skyrmions into future low-power-consumption flexible spintronics devices.

Eliminating Nearfield Coupling in Dense High Quality Factor Phase Gradient Metasurfaces

Tue, 01/07/2025 - 08:00

A strategy for fully suppressing nearfield coupling is reported between subwavelength separated meta-atoms with arbitrarily large resonant quality factors, opening the door to dynamic high resolution wavefront shaping with vanishingly small refractive index biasing. The platform provides a route for densely arrayed high Q metasurfaces with independently addressable meta-atoms, paving the way for highly efficient nonlinear and dynamic wavefront shaping.


Abstract

High Q phase gradient metasurfaces are promising for revolutionizing light manipulation, but near-field coupling typically forces a trade-off between quality factor and resolution. Here, a strategy for eliminating coupling-based nonlocal effects in wave shaping metasurfaces composed of meta-pixels is presented with arbitrarily long resonant lifetimes arranged with sub-diffraction spatial resolution. By working at a zero-coupling regime introduced by the interference between enhanced longitudinal and transverse electric fields, the tradeoff between Q and resolution no longer exists. Numerical demonstrations show that metasurfaces with quality factors of a few million and resolution <λ/1.6 can produce beam-splitting to angles of ±53° and beam-steering to an angle of 33° with diffraction efficiencies over 90% via refractive index modulations of just 2 × 10−6 and 7 × 10−6, respectively. Experimentally, the signature of a zero-coupling regime is discovered in the form of a sign flip in the angular dispersion with resonant wavelength, which validates the scheme. Aside from triangulating a perfect decoupling configuration, one of the fabricated nanofin-isolated metasurfaces with Q-factor >870 has a resonant wavelength that stays within the half linewidth for incident angles of −20° to 20°. This platform paves the way for combining precise wavefront shaping with highly efficient nonlinearity and rapid programmability.

Bioinspired Adaptive Sensors: A Review on Current Developments in Theory and Application

Tue, 01/07/2025 - 07:51

This review comprehensively summarizes the recent progress in the design and fabrication of sensory-adaptation-inspired devices and highlights their valuable applications in electronic skin, wearable electronics, and machine vision. The existing challenges and future directions are addressed in aspects such as device performance optimization, multimodal adaptive sensors, and system-level integration.


Abstract

The human perception system features many dynamic functional mechanisms that efficiently process the large amount of sensory information available in the surrounding environment. In this system, sensory adaptation operates as a core mechanism that seamlessly filters familiar and inconsequential external stimuli at sensory endpoints. Such adaptive filtering minimizes redundant data movement between sensory terminals and cortical processing units and contributes to a lower communication bandwidth requirement and lower energy consumption at the system level. Recreating the behavior of sensory adaptation using electronic devices has garnered significant research interest owing to its promising prospects in next-generation intelligent perception platforms. Herein, the recent progress in bioinspired adaptive device engineering is systematically examined, and its valuable applications in electronic skins, wearable electronics, and machine vision are highlighted. The rapid development of bioinspired adaptive sensors can be attributed not only to the recent advances in emerging neuromorphic electronic elements, including piezoelectric and triboelectric sensors, memristive devices, and neuromorphic transistors, but also to the improved understanding of biological sensory adaptation. Existing challenges hindering device performance optimization, multimodal adaptive sensor development, and system-level integration are also discussed, providing insights for the development of high-performance neuromorphic sensing systems.

Triboelectric Nanogenerators Enable Multifunctional Ice Accretion, Melting, and Interfacial Fracture Detection

Tue, 01/07/2025 - 07:50

Water impacting, freezing, melting, and being mechanically removed from the designed dielectric surfaces generates a triboeletric signal that can be used to detect various icing and de-icing scenarios. The charge transferred directly scales with the interfacial fracture mechanism, further validating triboelectricity as an excellent ice-detection platform, including in-flight on drones flying at subzero temperatures, as demonstrated.


Abstract

Triboelectric nanogenerators (TENGs) have significant potential to perform as sensors or compact electric power generators through the production of electrical charge during the frictional interactions between two dissimilar materials, such as liquids impacting solids. However, whether phase transitions generate a triboelectric response is not known. This study investigates the occurrence of triboelectrification during the water-ice phase transition using TENGs for real-time ice detection on critical engineering surfaces such as aircraft, wind turbine blades, and vehicles. TENGs are fabricated using aluminum electrodes and either polyethylene, silicone, or polytetrafluoroethylene as the dielectric. The freezing of water and the melting of ice are found to generate triboelectric current only during motion of the contact line, and the presence of ice can lessen additional charge transfer during continuous ice accretion. Further, ice type (rime versus glaze) can be differentiated during accretion by the initial transferred charge and how quickly the signal plateaus. It is observed that mechanical de-icing generates triboelectric charges that are proportional to the de-icing force, and this allows for the identification and quantification interfacial fracture mechanisms such as stress-controlled, toughness-controlled, and cavitation-controlled de-bonding. A prototype ice sensor is validated on a flying drone exposed to simulated rain under icing conditions, where it is able to detect both icing and de-icing in flight. The TENGs exhibited a signal-to-noise ratio as high as 83 dB, highlighting triboelectricity as a novel, real-time, and energy-efficient solution for ice detection and protection systems.

Heterogeneous Polymer Multilayers Enabling Photoresponsive Nonreciprocal Patterns for Information Encryption

Tue, 01/07/2025 - 07:49

Nonreciprocal optical patterns are fabricated using heterogeneous multilayers of photopatternable azopolymers and polyvinyl alcohol polarizers. The nonreciprocal optical patterns can only be read from one direction, providing a unique security feature for information encryption. The responsiveness of the nonreciprocal optical patterns and the mechanical robustness of the multilayers enable the design of flexible, portable, and wearable devices for information encryption.


Abstract

Society has a growing demand for information security. The development of nonreciprocal patterns is a new approach for high-security information encryption, but it is difficult to achieve due to its complexity in material design. Herein, heterogeneous polymer multilayers are designed to prepare nonreciprocal patterns for information encryption. The heterogeneous polymer multilayers are constructed by gluing polyvinyl alcohol (PVA) polarizers and photoresponsive azobenzene-containing polymers (azopolymers) via photocontrolled adhesion. Nonreciprocal optical patterns are fabricated via photopatterning of the azopolymer layer with polarized light. The information can only be decrypted from one direction of the nonreciprocal optical patterns. The nonreciprocal optical patterns are dynamic, which can be erased and rewritten with updated information via light irradiation. The nonreciprocal optical patterns can be further imprinted with diffraction elements, showing dual-mode optical signals. The nonreciprocal optical patterns with dynamic, dual-mode features enable high-security information encryption. Moreover, the heterogeneous polymer multilayers are flexible, bendable, and foldable, enabling the design of devices with nonreciprocal optical patterns for encryption in 3D space. The heterogeneous polymer multilayers with photoresponsive nonreciprocal patterns offer a solution for designing secure, updatable, and mechanically robust information encryption materials for flexible photonics, portable electronics, new anti-counterfeiting technologies, and wearable devices.

Ultrathin‐Film Small Molecule Mixed Conductors Exhibiting Ion‐Tunable Ambipolarity for High‐Performance Organic Electrochemical Transistors and Multivalued Logic Inverters

Tue, 01/07/2025 - 07:45

Employing an acceptor-donor-acceptor-donor-acceptor (A-D-A'-D-A) structural motif, single-component small-molecule mixed ionic-electronic conductors with ion-dependent ambipolarity are first developed for organic electrochemical transistors and inverters featuring ultrathin channel layers. Their outstanding figures-of-merit, remarkable voltage gains, and adaptability for ternary/quaternary logic operations signify significant advances in this field, highlighting their potential as versatile platforms for organic (bio)electronics with high sensitivity and high-density integration.


Abstract

Single-component, ultrathin ambipolar organic electrochemical transistors (OECTs) combined with multivalued logic (MVL) circuits offer new opportunities for advancing next-generation bioelectronic systems due to their low-power consumption, manufacturing simplicity, and high-density integration, central to which is the evolution of ambipolar organic mixed ionic-electronic conductors (OMIECs) as channel materials. However, small-molecule analogues remain unexplored to date for lack of well-defined molecular strategies. Herein, first two acceptor-donor-acceptor-donor-acceptor-type vinyl-linked bis-diketopyrrolopyrrole-core ambipolar small-molecule OMIECs are developed featuring multiple conformational locks. It is discovered that grafting shortened glycolated sidechains produces stronger solid-state aggregation, tighter lamellar stacking, and higher crystallinity, consequently elevating the ambipolar µC* figure-of-merit by over fourfold. Furthermore, the skillful manipulation of anionic species to facilitate oxidation doping enables significant increasement in p-type µC* (170 F cm−1 V−1 s−1) and a record-high n-type µC* of 360 F cm−1 V−1 s−1, especially at a channel thickness of sub-10 nm. Crucially, single-component OECT-based inverters constructed therefrom are for the first time demonstrated to accommodate ternary/quaternary logic, achieving a remarkable gain of 135 V/V. This work not only provides an effective molecular design strategy for creating high-performing ultrathin-film ambipolar small-molecule OMIECs, highlighting ionic doping effect on ambipolarity, but also demonstrates their potential in MVL circuits for organic bioelectronics applications.

Fine‐Tuning of Molecular Self‐Assembly Morphology via Synergistic Ternary Copolymerization and Side Chain Optimization of Low‐Cost Polymer Donors Toward Efficient Organic Solar Cells

Tue, 01/07/2025 - 07:44

Three new low-cost PTQ derivative donors PTQ17, PTQ18, and PTQ19 are rationally designed and synthesized by synergistic ternary copolymerization and side chain optimization strategies, to fine-tune the molecular self-assembly morphology. Due to ideal microscopic morphology of active layer and optimized energy level alignment, PTQ18-based binary and ternary organic solar cells achieve excellent efficiencies of 19.68% and 20.06%.


Abstract

Self-assembly morphology optimization of organic photovoltaic materials is crucial to improve the performance of organic solar cells (OSCs). Herein, three low-cost PTQ derivative donors, PTQ17, PTQ18, and PTQ19 are developed by synergistic ternary copolymerization and side chain optimization of utilizing different benzothiadiazole (BT) units, to fine-tune molecular self-assembly morphology. PTQ17, containing difluorinated BT, shows the tightest π-π packing and strongest molecular crystallinity, leading to excessive molecular aggregation and phase separation morphology in active layer. In contrast, PTQ19, containing dialkoxy-substituted BT, has the weakest molecular crystallinity, resulting in the worst long-range ordered molecular packing and the smallest phase domains in active layer. Remarkably, PTQ18, containing monofluorinated and monoalkoxy-substituted BT, has moderate molecular crystallinity and the best compatibility with acceptor, resulting in the most ideal microscopic morphology of active layer with desirable domain size and phase separation features. In result, the PTQ18-based binary OSC achieves an outstanding efficiency of 19.68%; and further optimized energy level alignment leads to an enhanced PCE of 20.06% in the PTQ18-based ternary device. This work demonstrates the importance of self-assembly morphology modification of organic photovoltaic molecules in improving performance of OSCs, and it has guiding role in design of high-performance organic photovoltaic materials.

Catalytic Solder Fuses Solid‐Solid Interfaces for All‐Solid‐State Lithium‐Sulfur Batteries

Tue, 01/07/2025 - 07:42

A catalytic “soldering” strategy based on TiS2 enables in situ formation of amorphous TiS4 and Li-Ti-P-S-Cl interphases, which promote seamless interfacial fusion and significantly enhance Li+ transport and catalytic kinetics. The resulting all-solid-state lithium-sulfur batteries deliver outstanding areal capacity and long-term stability under high sulfur loading.


Abstract

All-solid-state lithium-sulfur batteries (ASSLSBs) have garnered significant research interest due to their inherent safety and high energy density. Nevertheless, their practical applications remain constrained by the sluggish sulfur reaction kinetics. While catalytic strategies have been demonstrated to facilitate sulfur conversion, their efficacy is fundamentally constrained by the lack of interfacial continuity. Thus, there is an urgent need for interfacial fusion to achieve such continuity and construct efficient catalytic interfaces. In this work, an amorphous interfacial fusion strategy using TiS2 as a catalytic “solder”, enabling intimate integration among sulfur, the catalyst, and the solid-state electrolyte is proposed. Upon reacting with sulfur and the sulfide-based solid electrolyte, TiS2 induces the in situ formation of amorphous TiS4 and Li-Ti-P-S-Cl interfacial phases. These amorphous phases facilitate interfacial “soldering”, creating integrated catalytic interfaces that enhance Li+ transport and catalytic efficiency. As a result, the optimized ASSLSBs show a reversible specific capacity of 720 mAh g−1 after 2000 cycles at 1 C. It also delivers a high areal capacity of 7.05 mAh cm−2 at a sulfur loading of 4.0 mg cm−2. This interfacial fusion strategy offers a promising pathway toward the practical development of high-performance ASSLSBs.

Zeolite Structure Direction: Metals with a Dual Role as Amine Coordinators and Siloxy Connectors

Tue, 01/07/2025 - 07:42

The dual role of metal ions as amine coordinators and siloxy connectors leads to the formation of new 3D silicate-based hybrid materials. Its isolated inorganic layers serve as a platform for the synthesis of novel porous materials. This paper serves as the seed of a new field in zeolite-zeotypes synthesis and presents the first example of a true coordination polymer-zeolite hybrid.


Abstract

Innovation in the synthesis of new zeolites is achieved primarily through the use of costly novel organic compounds as structure-directing agents (SDAs). Here, a novel type of structure-direction based on a metal-amine coordination polymer leading to a 3-dimensional silicate-based hybrid material, LEU-1, is presented. The Zn-amine polymer not only serves as an SDA, but also plays a practical role in extending the inorganic connectivity in the form of Zn-O-Si bonds. This dual-role mechanism leads to unique hybrids with huge potential for creating zeolite-like materials. It is demonstrated that by using the silicate layer in LEU-1 as a platform, two novel pure-silica zeolites can be generated. This synthesis strategy, rooted in the coordination diversity of metal-amines, opens the door to more novel zeolite structures.

Surface‐Engineering Cellulose Nanofibers via In Situ PEDOT Polymerization for Superior Thermoelectric Properties

Tue, 01/07/2025 - 07:42

A strategy for homogeneous in situ polymerization of poly(3,4-ethylenedioxythiophene) along cellulose nanofibril surfaces is presented. Featuring enhanced charge delocalization and exceptional durability under 2000 bends and 5000 abrasions, wet-heat aging, freezing, and UV aging tests, the conductive nanocellulose fibers maintain stable electrical conductivity and thermoelectric output—a key advance for nanocellulose wearables and flexible electronics.


Abstract

Cellulose nanofibrils (CNFs) are abundant and possess exceptional mechanical strength, but their intrinsic electrical insulation limits their application in wearable electronics. In this study, a versatile methodology is presented to produce highly conductive and durable CNFs through electrostatic potential-enhanced in situ polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT). Guided by molecular dynamics simulations, electrostatic interactions are controlled by tailoring the chain length of PEDOT, achieving homogeneous polymerization. Compared to conventional polymerization and blending methods, this approach prevented the self-aggregation of PEDOT crystallites, which would otherwise localize charge carriers and hinder electrical transport, as confirmed by scanning Kelvin probe microscope (SKPM). These fibers can leverage nanocellulose's capillary effects to rearrange PEDOT crystallites, thereby boosting electrical conductivity by 5 orders of magnitude over suboptimal samples. The conductive nanocellulose paper achieves superior electrical conductivity (91 S cm−1) and durability, retaining 90% of electrical properties over 2000 bending cycles, 5000 abrasion tests, and prolonged wet-heat aging, freezing, and UV aging, while also demonstrating stable thermoelectric performance with power factor exceeding 3.8 µW mK−2 and a promising device output of 46.6 nW. These findings advance the conventional notion that charge-transporting nanocellulose can only be obtained by carbonization, graphitization, or physical blending with conductive components, which further boosts its potential for wearable applications.

Biased Plasma Treated Nickel Oxide for High‐Efficiency Perovskite/Silicon Tandem Solar Cells

Tue, 01/07/2025 - 07:41

In situ biased plasma treatment (BPT) reconstructs the surface of sputtered Nickel oxide (NiOx), enabling controlled Ni3⁺/Ni2⁺ ratios and optimized surface roughness, thereby enhancing interfacial properties. This strategy enhances perovskite crystallinity and optimizes band alignment, resulting in power conversion efficiencies of 21.8% in single-junction and 32.1% (certified 31.7%) in tandem solar cells, with outstanding operational stability.


Abstract

Nickel oxide (NiOx) hole transport layer deposited by magnetron sputtering shows high stability, low cost, high reproducibility, and scalability for perovskite and tandem solar cells. However, the performance of perovskite and tandem solar cells with sputtered NiOx is limited by the defective interface and suboptimal energy band alignment. This work focuses on reconstructing the sputtered NiOx surface with in situ biased plasma treatment (BPT). It is demonstrated that in situ BPT following sputtering induces both physical and chemical changes on the NiOx surface, enabling a smoother and denser surface with controllable Ni3+/Ni2+ ratios. The in situ BPT NiOx is proven to be effective in improving the conductivity of NiOx, suppressing the non-radiation recombination, fine-tuning the energy band alignment, and facilitating the crystallinity of the perovskite. As a result, the power conversion efficiency (PCE) of wide bandgap perovskite solar cells is improved to 21.8% by the implementation of BPT NiOx. Further integrating the BPT NiOx into monolithic perovskite/silicon tandem solar cells results in a high PCE of 32.1% (certified 31.7%) with excellent operational stability.

Anisotropic Magnetic Heating for Adaptive Thermal Ablation

Tue, 01/07/2025 - 07:40

A bimorph thermal ablation probe is designed by integrating a heating layer containing magnetically aligned Fe3O4@SiO2 nanorods in PDMS and an actuation layer with NdFeB microparticles. Under alternating magnetic fields, anisotropic nanorods generate directional heating, and the application of a static magnetic field induces controlled probe bending to dynamically adjust nanorod orientation, thereby modulating heat generation for targeted ablation while minimizing collateral tissue damage.


Abstract

Thermal ablation provides minimally invasive treatment for cardiovascular and cerebrovascular conditions but risks damaging healthy tissues due to their low imaging contrast against diseased areas. This study introduces an adaptive thermal ablation probe leveraging anisotropic magnetic heating of magnetite nanorods pre-aligned within a polymer substrate. During magnetic pre-alignment, the nanorods form chain-like aggregates, enhancing their magnetic anisotropy and minimizing demagnetization effects. Under an alternating magnetic field, these features create a distinct difference in heat generation along the aggregates’ easy and hard axes. This probe utilizes a bimorph structure incorporating a heating layer with aligned nanorods and an actuation layer containing NdFeB microparticles. Exposure to static and alternating magnetic fields induces probe bending, adjusting nanorod orientation to modulate heat generation and prevent overheating. In vitro experiments demonstrate successful thrombus phantom ablation in both fluid flow and porcine artery models while preserving tissue viability. This innovative approach advances thermal ablation technology by offering a safer, more precise, and adaptive solution with a high potential for clinical translation.

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