Materials Horizons最新文献

Thermoelectric (TE) generators based on bismuth telluride (Bi₂Te₃) are recognized as a credible solution for low-grade heat harvesting. In this study, an combinative doping strategy of both the donor (Ag) and the acceptor (Ga) in Ag₉GaTe₆ as dopants is developed to modulate the microstructure and improve the ZT value of p-type Bi_0.4Sb_1.6Te₃. Specifically, the distribution of Ag and Ga in the matrix synergistically introduces multiple phonon scattering centers including lath twins, triple junction boundaries, and Sb-rich nanoprecipitates, leading to an obviously suppressed lattice thermal conductivity of 0.50 W m^-1 K^-1 at 300 K. At the same time, such unique microstructures of lath twins synergistically enhance the room-temperature power factor to 48.8 μW cm^-1 K^-2 and improve the Vickers hardness to 0.90 GPa. Consequently, a high ZT of 1.40 at 350 K and ZT_ave of 1.24 (300-500 K) are achieved in the Bi_0.4Sb_1.6Te₃ + 0.03 wt% Ag₉GaTe₆ sample. Based on that, a competitive conversion efficiency of 6.5% at ΔT = 200 K is obtained in the constructed 17-couple TE module, which exhibits no significant change in the output property after 30 thermal cycle tests benefiting from the stable microstructure.

Smart materials that adapt to various stimuli, such as light, hold immense potential across many fields. Photoresponsive molecules like azobenzenes, which undergo E-Z photoisomerization when exposed to light, are particularly valuable for applications in smart coatings, light-controlled adhesives, and photoresists in semiconductors and integrated circuits. Despite advances in using azobenzene moieties for stimuli-responsive adhesives, the role of push-pull electronic effects in regulating reversible adhesion remains largely unexplored. In this study, we investigate for the first time photo-controlled hydrogel adhesives of azobenzene with different push-pull electronic groups. We synthesized the monomers 4-methoxyazobenzene acrylate (ABOMe), azobenzene acrylate (ABH), and 4-nitroazobenzene acrylate (ABNO₂), and examined their effects on reversible adhesion properties. By incorporating these azobenzene monomers into acrylamide, dialdehyde-functionalized poly(ethylene glycol), and [3-(methacryloylamino)propyl]-trimethylammonium chloride, we prepared ABOMe, ABH, and ABNO₂ ionic hydrogels. Our research findings demonstrate that only the ABOMe ionic hydrogel exhibits reversible adhesion. This is due to its distinct transition state mechanism compared to ABH and ABNO₂, which enables efficient E-Z photoisomerization and drives its reversible adhesion properties. Notably, the ABOMe ionic hydrogel reveals an outstanding skin adhesion strength of 360.7 ± 10.1 kPa, surpassing values reported in current literature. This exceptional adhesion is attributed to Schiff base reactions, monopole-quadrupole interactions, π-π interactions, and hydrogen bonding with skin amino acids. Additionally, the ABOMe hydrogel exhibits excellent reversible self-healing capabilities, significantly enhancing its potential for injectable medical applications. This research underscores the importance of integrating multifunctional properties into a single system, opening new possibilities for innovative and durable adhesive materials.

The performance and stability of perovskite solar cells (PSCs) are critically influenced by the interfacial properties between the perovskite absorption layer and the electron transport layer (ETL). This study introduces a novel interfacial engineering approach using dipotassium 7-hydroxynaphthalene-1,3-disulfonate (K-NDS) as a multifunctional passivator to enhance both the SnO₂ ETL and the perovskite absorber layer. The sulfonic acid groups (-SO₃^-) in K-NDS effectively fill oxygen vacancies on the SnO₂ surface, while the hydroxyl groups (-OH) passivate dangling bonds, improving the crystallinity of the perovskite film. Additionally, the diffusion of K⁺ from the SnO₂ ETL into the perovskite layer optimizes energy level alignment, thereby enhancing charge carrier extraction and transport. This bifacial passivation strategy has significantly improved both the power conversion efficiency (PCE) and long-term stability of PSCs. The modified devices achieved a champion PCE of 23.00% and an open-circuit voltage (V_OC) of 1.172 V. Furthermore, these devices maintained 75% of their initial PCE even after 1000 hours of storage under indoor environmental conditions. This work demonstrates the effectiveness of synergistic interfacial passivation in advancing the performance and durability of PSCs.

Primary open-angle glaucoma (POAG) is the most common form of glaucoma and the leading cause of irreversible vision loss and blindness worldwide. Intraocular pressure (IOP) is the only modifiable risk factor, and prompt treatment to lower IOP can effectively slow the rate of vision loss due to glaucoma. Trabecular meshwork (TM) cells can maintain IOP homeostasis by correcting and adjusting the resistance to aqueous humor outflow in response to sustained pressure changes. TM cells' function is reduced, and membrane ion channels are impaired in POAG. The dysfunction of Large conductance Ca²⁺-activated K⁺ (BKCa) plays a central role in the pathogenesis of POAG. In this work, we targeted MXene nanoparticles (MXene-RGD) with piezoelectric response to TM cells in a 3D model of glaucoma in vitro as well as in the rabbit Transient Ocular Hypertension (OHT) Model in vivo. MXene-RGD gives the TM electromechanical transfer properties, while the self-enhancing and self-generated electricity properties of the TM are determined by the aqueous humor flow rate and the size of the deformation of the TM. MXene-RGD is nontoxic, as illustrated by a cell toxicity study and histological examination. In a 3D in vitro model of high-pressure glaucoma, whole-cell patch-clamp confirmed that piezoelectric stimulation turns on BKCa, which reduces the volume of the cell. MXene-RGD was injected into the anterior chamber with minimal trauma, i.e., anterior chamber injection, and specifically targeted to TM cells. The OHT model in vivo confirmed the potential IOP-lowering ability of MXene-RGD. We evaluated the ion channels involved in the reduction of IOP by MXene-RGD by pre-treatment with a BKCa channel blocker (iberiotoxin, IbTX) and a voltage-gated Ca²⁺channel blocker (nifedipine). Quantitative qPCR analysis showed that MXene-RGD inhibited the upregulation of mRNA expression levels of the myofibroblast marker α-smooth muscle actin (α-SMA) and the inflammatory response marker interleukin-6 (IL-6) induced by IOP. Histology confirmed that MXene-RGD attenuated IOP-induced proliferation and collagen production in the TM. Taken together, we present for the first time a minimally invasive surgical approach for targeting TM cells for POAG by utilizing piezoresponse nanomaterials to target BKCa to repair or awaken the ability of TM cells to regulate IOP homeostasis on their own.

The aerogels with low thermal conductivity and cross-linked 3D networks can be easily integrated with functional materials to maximize their functionalities, realizing diverse applications such as photothermal seawater desalination and photocatalytic uranium extraction. Sp²C-conjugated porous polymers (sp²C-CPPs) with robust and conjugated CC linkages are ideal photosensitizers for these applications, owing to their exceptional semiconducting properties as well as chemical stability. However, the limited processability and collectability of as-synthesized sp²C-CPP powders impede their extended applications. Herein, we report the preparation of robust sp²C-CPP (DHA-TMT and DBD-TMT) based aerogels via surface-initiated aldol polycondensation (SI-AP). The fully conjugated CC skeletons and electron-donating groups (-OH) endow the sp²C-CPP aerogels with excellent photothermal conversion efficiency (95.6%) and strong affinity for uranium adsorption. In particular, the DHA-TMT aerogel with hydrophilic porous channel exhibits a superb evaporation performance achieving ∼1.55 kg m^-2 h^-1 under AM 1.5 G while the fast mass transfer caused by photothermal conversion increases the uranium extraction capacity up to 1200 mg m^-2 in simulated seawater. Moreover, the sp²C-CPP aerogels demonstrate high stability under strong acid, base and brine solutions. This work shows a strategy for the preparation of uniform and high stability sp²C-CPP-based aerogels to simultaneously enhance their photothermal and photocatalytic performance.

A high-performance stealth platform is one of the crucial requirements in defence technology that could practically be realized by building effective microwave frequency selective surface (FSS) absorbers. Herein, we report the design and manufacturing of an absorber by tuning the rheology of cell architecture. Initially, a fan-shaped cell (10.4 mm²) was designed for its surface and bulk rheology. The FSS overlayer composition was investigated using SEM, EDX, and XRD and tuned for 0.25% carbon: 1.5% silver to achieve the ink resistivity ∼255 Ω □^-1. The bulk rheology was optimized for air (Roha) spacer (thickness ∼2.8 mm), interlayer dielectrics (0.2 mm each), carbon composition (5%), and cell dimension (10.2 mm). Analyses are presented for absorption loss (R_C, dB), bandwidth (GHz), resonance dispersion, and constitutive (ε, μ) parameters, compounded with an equivalent circuit model with the settings R = 273.55 Ω, L = 2.25 nH, C = 0.057 pF and the Fabry-Perot reactance mode@10 GHz. The bi-modal response was investigated for induced polarization, electromagnetic fields, volume power distribution, and angular (Θ = 0°-50°) and rotational stability (Φ = 0°-90°) against TE/TM incidences. The FSS pattern was implemented using a screen printing technique to fabricate a prototype absorber and subjected to the free space measurements in an anechoic chamber. The prototype behaviour was found to be commensurate with the simulated performance, thereby achieving a figure of merit of R_C ∼-25 dB@10 GHz, accessible bandwidth 4 GHz (in X band) by using the thickness of 0.057 λ₀. Details are presented in this study.

This review comprehensively covers the translation from batch to continuous flow synthesis of metal nanowires (i.e., silver, copper, gold, and platinum nanowires) and their diverse applications across various sectors. Metal nanowires have attracted significant attention owing to their versatility and feasibility for large-scale synthesis. The efficacy of flow chemistry in nanomaterial synthesis has been extensively demonstrated over the past few decades. Continuous flow synthesis offers scalability, high throughput screening, and robust and reproducible synthesis procedures, making it a promising technology. Silver nanowires, widely used in flexible electronics, transparent conductive films, and sensors, have benefited from advancements in continuous flow synthesis aimed at achieving high aspect ratios and uniform diameters, though challenges in preventing agglomeration during large-scale production remain. Copper nanowires, considered as a cost-effective alternative to silver nanowires for conductive materials, have benefited from continuous flow synthesis methods that minimize oxidation and enhance stability, yet scaling up these processes requires precise control of reducing environments and copper ion concentration. A critical evaluation of various metal nanowire ink formulations is conducted, aiming to identify formulations that exhibit superior properties with lower metal solid content. This study delves into the intricacies of continuous flow synthesis methods for metal nanowires, emphasizing the exploration of engineering considerations essential for the design of continuous flow reactors. Furthermore, challenges associated with large-scale synthesis are addressed, highlighting the process-related issues.

All-solid-state lithium-sulfur batteries (ASSLSBs) using poly(ethylene oxide) (PEO) electrolytes offer significant advantages in energy density and safety. However, their development is hampered by the slow Li⁺ conduction in solid polymer electrolytes and sluggish electrochemical conversion at the cathode-electrolyte interface. Herein, we fabricate a self-healing poly(β-amino ester) with a comb-like topological structure and multiple functional groups, synthesized through a Michael addition strategy. This material modifies the PEO-based solid-state electrolyte, creating fast Li⁺ transport channels and improving polysulfides conversion kinetics at the electrode surface. Consequently, both modified all-solid-state lithium symmetric cells and lithium-sulfur batteries exhibit improved electrochemical performance. This work demonstrates an expanded interpenetrating macromolecular engineering approach to develop highly ion-conductive solid polymer electrolytes for ASSLSBs.

A memristive crossbar array can execute Boolean logic operations directly within the memory, which is highly noteworthy as it addresses the data bottleneck issue in traditional von Neumann computing. Although its potential has been widely demonstrated, achieving practical levels of operational reliability and computational efficiency remains a challenge. Here, we introduce a three-input majority logic gate supported by near-memory operations, serving as a universal gate and achieving both robust reliability and high efficiency in versatile logic operations. We fabricated a highly reliable HfO_x-based memristive array, incorporating a series resistor to increase the reset voltage of the memristor, thereby increasing the operational voltage margin of the gate operation. This ensured reliable operation of the majority gate, resulting in successful experimental proof of combined 1-bit full adder and subtractor operations performed in 5 steps using 7 cells. Additionally, we propose that an N-bit parallel prefix adder (PPA) operation is possible in O(log₂ N) steps, by taking advantage of the parallel operation capability of the majority gate. This achieves 8.5× higher spatiotemporal efficiency than the previously reported NOR-based logic system in 64-bit adder operation. Moreover, as N increases, the spatiotemporal efficiency further improves, which significantly enhances the applicability of memristive logic-in-memory.

Visually monitoring micro-crack initiation and corrosion failure evolution is crucial for early diagnosis of structural health and ensuring safe operation of infrastructures. However, existing damage detecting approaches are subject to the limited-detection of heterogeneous structures, intolerance of harsh environments, and challenge of quantitative analysis, impeding applications in structural health monitoring (SHM). Herein, we present a stretchable, semi-quantitative, instrument-free, supramolecular SHM sensor by integrating a polyurea elastomer with sensitive corrosion-probes, enabling localized corrosion monitoring and quantification of failure dynamics. Initially, a correlation between visual monitoring signals and structural health status is proposed, and sensor-based image processing software that accurately quantifies structural failure indicators (crack scale, corrosion reactivity and deterioration status) is proposed. Moreover, this sensor can be fabricated as multiple derivatives: a coating or patch covered on metallic substrates and an ionic-responsive test strip, ensuring real-time detection of the initiation of pitting, degradation events of metallic components and convenient monitoring of ion concentrations in corrosive media. Furthermore, the inherent geometric plasticity and dynamic hydrogen-bonded network validates the reliability for heterogeneous components and stability under extreme environments of sensors. This portable, smart SHM strategy established the channel-transformation model from corrosion dynamics to visual signals, exhibiting prospects for structural monitoring in offshore energy-harvesting equipment.