Materials Horizons最新文献

Global water scarcity poses a critical challenge, particularly in arid and semi-arid regions where access to fresh water is limited. Atmospheric water harvesting (AWH) is an innovative solution for capturing moisture and converting it into usable water. Owing to their absorption capacity and cost-effectiveness, hygroscopic salts, such as lithium chloride (LiCl), are of great importance for AWH; yet their practical applications are impeded by issues such as clumping and leakage. To address these challenges, this study combines thermoplastic polyurethane with LiCl using selective laser sintering 3D printing technology to fabricate bio-inspired hierarchical porous cones (HPCs). LiCl particles are embedded in polymeric scaffolds, exposing more active areas for water sorption and release, which favors both AWH and further water evaporation kinetics of the 3D-printed object. The as-prepared HPCs demonstrate a moisture absorption as high as 2.65 g g^-1 at 80% relative humidity, exhibiting exceptional water-harvesting performance. The 3D-printed objects maintain stable performances over multiple absorption-release cycles, validating their effectiveness under real-world conditions. A 3D-printed HPC array has been demonstrated, which can produce 1.89 kg kg^-1 day^-1 of AWH under natural sunlight. This work provides insights into the development of efficient AWH systems and lays the groundwork for future innovations in sustainable water sourcing.

Area-selective atomic layer deposition (AS-ALD) has emerged as a promising bottom-up approach for achieving precise 3D patterning in advanced nanofabrication. In this study, Ru AS-ALD on SiO₂versus Si₃N₄ surfaces was investigated using cyclohexane carboxaldehyde (CHAD) as a small molecule inhibitor (SMI). CHAD exhibited selective adsorption on Si₃N₄, enabling the selective deposition of Ru when tricarbonyl-(trimethylenemethane)-ruthenium (TRuST) and H₂O were used as the precursor and reactant, respectively. A re-dosing strategy, validated by Monte Carlo (MC) simulations, was introduced to improve deposition selectivity. Compared to a single dose of CHAD, which showed selectivity against Ru for 7 nm (50 cycles), the re-dosing strategy improved the selectivity up to 27 nm (200 cycles). This improvement of selectivity was mainly due to high inhibitor adsorption density, which reduced unoccupied adsorption sites that could act as nucleation sites for precursors. The Ru AS-ALD optimized using the re-dosing strategy was applied to 2D line patterns and 3D trench patterns, consisting of SiO₂/Si₃N₄. 2D patterns achieved 26.5 nm (200 cycles) of selective deposition, accompanied by an undesirable lateral growth of 18.8 nm. Conversely, 3D patterns achieved 15 nm (100 cycles) of selective growth without lateral growth observation. The critical growth difference is mainly attributed to the surface topology: 3D trench structures provide a more effective physical and chemical barrier compared to 2D structures. Consequently, the results collectively demonstrate the potential of the re-dosing strategy in selectivity improvement and the critical role of topography in achieving reliable AS-ALD for 3D nanofabrication.

Transient light phenomena in biological systems are predominantly orchestrated by chemical reaction networks, with enzymes serving as key modulators. Inspired by these natural processes, we have developed enzyme-regulated, broad-spectrum artificial light-harvesting nanoaggregates capable of pH-clock-driven transient emissions. pH-Adaptable AIEgen-based nanoaggregates have been implemented in this study that can sequester a suitable FRET acceptor in their hydrophobic domain, leading to multi-colour emissions. These nanoaggregates can be temporally regulated with a chemoenzymatic pH clock, which generates time-programmed emissive colours with different FRET donor-acceptor combinations. The resulting multicoloured transient emissions closely resemble the fleeting luminescence observed in fireflies. Such time-responsive nanoaggregates and their dynamic emissive behaviour offer promising utility for information encryption with inherent anti-counterfeiting capabilities. As data encryption commonly relies on cryptic coding, we demonstrate time-encoded information encryption using ASCII, Morse, and 4-bit codes derived from these emissive systems. Herein, time becomes a crucial parameter that enhances the security of code-based data storage. The synergy of simple molecular design, a complex multicomponent environment, adaptive functionality, and synchronised temporal modulation collectively summarises the essential characteristics of biological light emission.

Integration of sensing, memory, and computing functionalities within a single device is a key step towards the development of efficient and compact artificial visual systems. Halide perovskite based memristors are promising candidates for such neuromorphic platforms due to their inherent optoelectronic properties and resistive switching capabilities. Using lead free layered double perovskites based on 1,4-phenylenedimethylammonium (PDMA) and benzylammonium (BzA) of (PDMA)₂AgBiX₈ and (BzA)₄AgBiX₈ (X = I and Br) compositions, we show that field and light-driven migration of halide ions and lattice incorporated Ag⁺ governs resistive switching and synaptic processes through an intrinsic mechanism, enabling electrical and optical synaptic responses. Depending on how ionic redistribution is stabilized or allowed to relax under different electrode and architectural boundary conditions, the same material exhibits both non-volatile memory and diffusive (volatile) switching essential for mimicking dynamic synaptic and neuronal processes. In solar cell configurations, the built-in junction field couples photocarrier generation with ionic motion, allowing zero-bias optical synaptic plasticity and self-powered operation for potential in-sensor computing. Electrical and optical synaptic responses emerge from this unified ion-dynamic process. Electrode and temperature dependence studies, transient measurements, polarity-switching analysis, and impedance spectroscopy provide consistent mechanistic signatures across operating modes. These findings position lead-free layered double perovskites as multifunctional and sustainable materials for neuromorphic technologies.

Natural organisms contain tissues like pearl layers, muscles, and bones with multiscale, multilevel ordered structures, which are challenging for biomimetic material fabrication. This study introduces a versatile method combining cellulose nanocrystal (CNC) shear-induced orientation under fluid forces with DLP 3D printing to create 3D multilevel ordered biomimetic architectures. Using cancellous bone's trabecular branching geometry as a model, a DLP-printed GelMA sacrificial template-complementary to the target structure and enzymatically degradable-was filled with CNC/hyaluronic acid methacrylate (CNC/HAMA) bioink. Within the template's channels, CNCs and HAMA chains oriented along fluid shear forces, forming three-pronged macroscopic architectures mimicking bone trabeculae. Micro/nanoscale analysis showed a Hermans orientation factor of ∼0.76 for CNC/HAMA synergistic alignment, with CNCs achieving ∼70% orientation, enabling ordered nanoscale arrangement. Oriented CNC/HAMA fibers further established microscale order. This approach bridges a complex macroscopic geometry with a 3D cross-scale hierarchical ordered alignment, effectively replicating natural tissues' multilevel structure and enhancing mechanical properties compared to unstructured counterparts. It provides a robust strategy for effectively controlling the 3D molecular orientation within the confined 3D-printed macroscopic structures.

Hybrid metal halides attract significant attention in materials science, chemistry, and photonics due to their attractive structural, electronic, and optical properties. However, zero-dimensional (0D) hybrid indium halides are still in their infancy. We report the first isomeric 0D indium halide single crystals showing green and delayed yellow emissions. Single-crystal X-ray structures reveal that these emissions originate from crystals with the molecular formula (C₁₀H₂₂N₂)₄In₄Br₂₀, consisting of organic ligands, InBr₆ octahedra, and InBr₄ tetrahedra. While both crystals carry eight corner-sharing and two face-sharing InBr₆ octahedra, the four face-sharing InBr₄ tetrahedra in the green-emitting isomer and two inner InBr₄ tetrahedra in the yellow-emitting isomer mark the crystal isomerism, leading to distinct optical properties. The green-emitting crystals exhibit short excitonic lifetimes, whereas the radiative recombination in the yellow-emitting crystals is delayed by several hundred nanoseconds and redshifted, indicating a self-trapped exciton behaviour with a large Huang-Rhys factor and high activation energy. The structural and optical properties of the isomeric single crystals offer insights into the importance of developing 0D metal halides with multi-colour and delayed emission for sensors, LEDs, and displays.

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In the realm of sensing, piezoionic systems have emerged as innovative tools for perceiving tactile sensations through mechanical-to-ionic transduction, mimicking biological signal production and transmission. To date, the biomimetic transduction mechanism and strategies for engineering the transduction efficiency remain not fully understood and underutilized. This review provides the fundamentals of mechanical-to-ionic transduction for efficient self-powered sensing, identifying the most crucial structural and operating parameters governing the generation of a transient signal output with respect to the migration and redistribution of ions upon mechanical stimulation. It also examines the recent strategies for efficiently converting mechanical keystrokes into electrical signals through performance-driven structural design, thereby maximizing piezoionic voltage generation. This involves engineering ion transport and fluid flow through porosity, microphase separation, conductive pathways and structural gradients. With respect to piezoionic effect-based applications, this review highlights the promising potential of polymeric, ionic materials in soft wearable electronics, ionic skins, tissue engineering, biointerfaces and energy harvesting.

Bacterial infection theranostics combining antibacterial therapy and real-time diagnosis can effectively advance the healing process. Near-infrared (NIR) light has been widely utilized for antibacterial photothermal therapy (PTT) and visible light can provide visual cues for the status of treatment, whereas the lack of modulating light propagation hinders the development of high-performance light-based infection theranostics. Here, inspired by the hierarchical micro/nano-structures of panther chameleon skin composed of deep- and superficial-iridophores responsible for regulating NIR and visible light propagation, respectively, a photonic crystal hydrogel is developed for enhanced antibacterial PTT and colorimetric monitoring of pH and treatment temperature. The deep layer composed of large-sized particles in the hyaluronic acid methacryloyl-polyacrylamide hydrogel matrix exhibits a photonic bandgap overlapping NIR light, acting as a universal platform for boosting the photothermal conversion efficiency (PCE) of embedded photothermal agents. As typical examples, 1.75-, 1.80-, and 1.94-fold increases in PCEs are achieved for embedded carbon black, carbon nanotubes, and MXenes, respectively. The superficial layer consisting of small-sized particles and a poly(2-(dimethylamino)ethyl methacrylate) hydrogel matrix is responsible for visible light modulation, exhibiting rapid, high-sensitivity, and broad-range color variations at different pH/temperatures. Benefiting from these light modulation capabilities, high-efficacy and multifunctional bacterial infection theranostics are realized, synergistically facilitating the healing of infected wounds.

A major challenge in organic single-component photocatalysts (SCPCs) for hydrogen (H₂) generation is their intrinsically inefficient exciton separation and charge generation. To address this, we designed two thienopyridine-fused benzodithiophene (TPBDT) molecules, TPBDT-2FIC and TPBDT-INCNO1, featuring wide bandgaps, extended coplanar π-conjugated backbones, and small Stokes shifts to improve molecular packing and exciton diffusion. TPBDT-INCNO1 incorporates a cyclic imine group that enables strong coordination with Pt co-catalysts through Pt-N σ- and π-bonding interactions. The electron density on the imine nitrogen is successfully tuned to facilitate efficient Pt deposition. Molecular dynamics simulations and X-ray scattering analyses confirm enhanced core-core interactions and improved packing of TPBDT-INCNO1 in nanoparticles (NPs) compared to Y6. This tight packing, along with a small SS, leads to efficient exciton diffusion to the NP surface with an extended exciton lifetime (1.66 ns). Approximately 70% of excitons are quenched via rapid hole transfer (∼1 ns) to L-ascorbic acid, generating long-lived electrons that are effectively quenched by Pt. As a result, TPBDT-INCNO1-based NPs exhibit high hydrogen evolution rate of 102.5 mmol h^-1 g^-1, significantly outperforming the Y6 reference. This study demonstrates key molecular design strategies for advancing SCPCs for efficient solar-driven H₂ production.