Advanced Materials Technologies最新文献

Space-Time Coding Metasurfaces

In article number 2302164, Yan Shi and co-workers present a space–time coding metasurface to achieve multiple hologram imaging. Via the space-time coding scheme, the magnitude and phase of the higher-order harmonics can be accurately and rapidly controlled. The designed metasurface enables near-field holographic reconstruction of two different images on an imaging plane by means of ±1st order harmonics, and simultaneous realization of versatile functions including hologram imaging and beam steering or hologram imaging and orbital angular momentum wave generation.

Programmable Meta-Reflectors

In article number 2400006, Shah Nawaz Burokur and co-workers present an intelligent connected platform based on a programmable metasurface, capable of performing multiple tasks in dynamic background environments. The versatility of this platform makes it a good candidate for the adaptive orientation of electromagnetic waves in future wireless communication systems, leveraging collective intelligence for optimized signal management.

Bioartificial Vascular Grafts

In article number 2301785, Rouven Berndt and co-workers develop a 4D bioprinting strategy for the manufacturing of small-diameter, vascular grafts. Accordingly, a bio-ink is synthesized containing a hybrid molecule from sodium alginate and collagen peptide and combined with endothelial progenitor cells. After maturation, the grafts show characteristics similar to those of human veins.

Si-Based Hybrid Solar Cells

In article number 2301966, Chia-Yun Chen and co-workers demonstrate MoS₂@carbon colloid dots (CCDs) blended in PEDOT:PSS layer as a photoactive p-type counterpart that provides additional gain from varying the photonic-inactive feature of PEDOT:PSS into a sunlight-responsive configuration. A noticeable improvement in the conversion efficiency of 16.1% with 1.6 times of efficiency enhancement, outperforming the bare conventional hybrid solar cells, is presented.

Advanced design methods and manufacturing techniques are crucial for developing thermal management structures, essential for the efficient operation of complex equipment. This study provides a thorough review of design methodologies and advanced manufacturing technologies for thermal management materials and structures. It identifies key challenges and critically evaluates the integration of innovative design principles, such as biomimicry and topology optimization, into thermal management solutions. The analysis delves into the evolution of design theories and preparation techniques, with a specific focus on modern needs and research directions, particularly highlighting components fabricated using additive manufacturing and their effectiveness in meeting advanced thermal management requirements. Current research focuses on designing structures tailored to various cooling methods, including air-cooling, liquid-cooling, heat exchanger cooling, and heat pipe cooling. These designs utilize phase change materials, electrocaloric cooling, and thermoelectric cooling materials to achieve optimal thermal management performance. Additionally, emerging innovations like solid-liquid mixed heat transfer and the elastocaloric effect are garnering increased interest. Enhancing the design of thermal management structures through rigorous numerical simulations is critical for improving engineering applicability. However, overcoming challenges related to the commercialization and practical utilization of these advanced structures remains a pressing need.

Catalytic valveless micropumps, and membraneless fuel cells are the class of devices that utilize the decomposition of hydrogen peroxide (H₂O₂) into water and oxygen. Nonetheless, a significant obstacle that endures within the discipline pertains to the pragmatic open circuit potential (OCP) of hydrogen peroxide FCs (H₂O₂ FCs), which fails to meet the theoretical OCP. Additionally, bubble formation significantly contributes to this disparity, as it disrupts the electrolyte's uniformity and interferes with reaction dynamics. In addition, issues such as catalyst degradation and poor kinetics can impact the overall cell efficiency. The development of high-performance H₂O₂-FCs necessitates the incorporation of selective electrocatalysts with a high surface area. However, porous micro-structures of the electrode impedes the transport of fuel and the removal of reaction byproducts, thereby hindering the attainment of technologically significant rates. To address these challenges, including bubble formation, the review highlights the potential of integrating electrokinetic and bubble-driven micropumps. An alternative approach involves the spatiotemporal separation of fuel and oxidizer through the use of laminar flow-based fuel cell (LFFC). The present review addresses multifaceted challenges of H₂O₂-powered FCs, and proposes integration of electrokinetic and bubble-driven micropumps, emphasizing the critical role of bubble management in improving H2O2 FC performance.

Animal-borne biologging technology allows researchers to understand the physiological responses of wild animals, especially songbirds, to environmental changes. Songbirds are of interest in studying these responses because of their visibility and relatively small body size yet high energetic demand of their various life-history stages (e.g., molt, migration, breeding). Previous methods for monitoring responses, such as heart rate activity, have relied on surgical implantation of electrodes connected to bulky electronic devices which affect the well-being of birds, indirectly influence bird behavior and create stress artifacts. A non-invasive, lightweight solution is needed. This study introduces eutectogels, a long-lasting gel made from deep eutectic solvents, combined with conductive threads and a wireless device to monitor the heart rate of house sparrows noninvasively through skin contact. In this work, heart rate and respiration rate measurements are validated on birds under anesthesia. These tests are repeated on birds that are awake but restrained. The eutectogel outperforms commercial electrodes and gels, yielding high signal-to-noise ratio measurements on restrained birds. The respiration rate is extracted and processed electronically from motion artifacts in the recorded signals without the need for a separate dedicated sensor. The system shows promise for future field studies on free-living species.

Wearable power sources are envisioned since their development promises to speed up the widespread application of wearable devices in different areas, such as healthcare, smart-city management, and robotics. Here, the 4′-((9,10-anthraquinone-2-yl)oxy)butyrate (2-BEAQ), an anthraquinone derivative, is synthesized, and further applied for producing a redox-active shear-thinning hydrogel (BEAQ-gel). The gel comprises cylindrical aggregates of 2-BEAQ molecules dispersed within a water matrix, interconnected through ionic, ion-dipole, and hydrogen bonding interactions. BEAQ-gel also presents interesting rheological characteristics and composition tunability since it can be produced in a large range of concentrations. This improved redox 3D hierarchical network also makes the network capable of retaining high quantities of potassium hydroxide, thereby enhancing conductivity. By coupling BEAQ-gel with Ferricyanide the development of a wearable battery is demonstrated, which exhibits an output voltage of 0.89 V even when bent at a 180° angle, making it suitable for powering wearable devices. This work presents an innovative alternative for the production of wearable devices, from the design of the anode and cathode materials to the wearable casing and demonstrates the use of redox-active low-molecular-weight-gel (LMWG) as an active material of a microbattery giving a valuable glimpse to the further development of wearable energy storage devices.

The roll-to-roll (R2R) process for fabricating elastic substrates is essential for the social implementation of next-generation stretchable devices with soft interfaces. In recent years, there is a growing demand for soft heterostructures with multiple monolithically patterned organic materials. However, a continuous processing technique for substrates with heterostructures patterned using highly stretchable wiring has not yet been developed. Conventional manufacturing methods for stretchable electronics lack production capacity. This study introduces an R2R-based method for the continuous production of multilayered substrates composed of various elastic materials, integrated with liquid metal (LM) wiring, suitable for stretchable electronics. Continuous fabrication of polymer films is achieved with pattern areas as small as 0.78 mm², using three different polymers varying in hardness. The R2R coating process, paired with liquid metal wiring dispensing printing, allows for the creation of lines as fine as 140 microns. This process supports the batch production of 15 stretchable hybrid devices at a time and enables the creation of large-area devices up to 400 cm². The fabrication technique developed herein holds promise for the future manufacturing of not only stretchable electronics but also cutting-edge soft electronics like smart packaging. This is expected to be a factor leading to the commercialization of stretchable electronics.