Advanced Materials Technologies最新文献

Liquid crystal display (LCD) vat photopolymerization (VPP) is gaining popularity in both industry and research due to its cost-effectiveness compared to other polymer-based 3D printing methods. However, surface quality remains a critical limitation, primarily due to the black matrix present between the active pixels of the LCD panel. Pixelation and staircase effects significantly degrade the surface finish and functional performance of printed parts. In this study, a voltage-tunable polymer-dispersed liquid crystal (LC) film is introduced as a secondary optical interface between the LCD panel and the resin vat. By varying the input voltage, the LC film enables tunable light scattering, diffuses sharp pixel boundaries, and smooths the projected mask image. This results in up to 95% reduction in surface roughness compared to the standard No LC condition. Improved surface smoothness enhances interlayer bonding, reduces stress concentration zones, and leads to substantial gains in tensile and flexural strength, including energy absorption. Additionally, the light transmittance of printed parts improves without post-processing. A resolution study confirms that features down to 2-pixel width remain resolvable, satisfying the Rayleigh criterion. This scalable and hardware-compatible strategy effectively enhances surface quality and mechanical performance in LCD VPP without compromising resolution.

Organic-inorganic hybrid perovskite materials have gained substantial research attention in the field of photodetectors (PDs) due to their remarkable optoelectronic properties and cost-effective fabrication process. However, their performance and stability are often limited by the defects on the surface and/or at the grain boundaries of perovskite film. Herein, two zwitterionic molecules, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (DMAPS) and 3-[bis[2-(methacryloyloxy)ethyl](methyl)ammonio]-1-propanesulfonate (BDMAPS) are introduced, as processing additives for perovskite materials. Since DMAPS and BDMAPS contain both negatively and positively charged moieties, they can provide excellent effectiveness for defect passivation. Additionally, their vinyl groups participate in in-situ cross-linking reactions under mild reaction conditions, enabling the formation of 3D polymer passivation network that strengthens the structural integrity of the perovskite. Importantly, owing to the higher cross-linking density of BDMAPS, perovskite PDs (PPDs) with BDMAPS additive exhibit improved device performance, achieving a specific detectivity of 1.50 × 10¹⁴ Jones and a responsivity of 0.52 A W⁻¹, which represents the highest reported value to date for self-powered PPDs. Very encouragingly, the unencapsulated PPDs with BDMAPS additive exhibit excellent shelf-stability even under high humidity conditions. This work highlights the potential of additive engineering in achieving efficient and stable PPDs, paving the way for the commercialization of next-generation PDs technology.

The necessity for both residential and commercial security in the modern world is emphasizing the search for an automatic security alarm sensor that can identify unwanted intrusion. Herein, a flexible, transparent, high-performance piezoelectric nanogenerator (PNG) using BaSnO₃ quasi-1D nanorods/PVDF nanocomposite is engineered. The high aspect ratio of quasi-1D BaSnO₃ nanorods helps to achieve the percolation threshold with a smaller volume fraction and also makes the nanocomposite films more sensitive when mechanical deformation is employed. The nanocomposite film containing 3 wt.% BaSnO₃ shows the highest electroactive phase of 84%. The optimized PNG exhibits the highest open circuit voltage, short circuit current, and power density of 46.21 V, 5.04 µA, and 22.2 µW cm⁻² respectively under a force of 10 N. A 4.7 µF capacitor is charged and eight commercial LEDs are illuminated by the device. Additionally, the device is tested as a different human motion sensor. More importantly, the security alarm sensitivity for the device is demonstrated while opening the door. The buzzer rings along with the LED glows due to the bending strain on the piezoelectric nanogenerator. Therefore, the proposed PNG has the potential to be used as a security sensor, human motion sensor, and mechanical energy harvester.

Liquid crystal polymer networks (LCNs) are soft, anisotropic materials that combine the order and responsiveness of liquid crystals (LCs) with the mechanical stability of polymer matrices. By polymerizing mesogenic monomers within their LC phase, LCNs retain orientational order while gaining robustness and stimuli-responsiveness. Advances in molecular design, alignment techniques, and crosslinking chemistry have enabled precise control over structure and function across multiple length scales. In addition, emerging approaches such as additive manufacturing, “click” chemistry, and dynamic covalent bonding further expand the design space toward reconfigurable and sustainable materials. These materials exhibit programmable and reversible responses to heat, light, and electric or magnetic fields, enabling applications in soft actuation, adaptive optics, and dynamic surfaces. Cholesteric LCNs offer tunable optical properties via pitch modulation, which are exploited in sensors, smart windows, and mirrorless lasers. Nanoporous LCNs provide well-defined nanoscale pathways for separation and electrochemical applications. This review highlights how molecular alignment, network formation, and processing strategies converge to define material performance and multifunctionality. Key challenges remain in achieving scalable fabrication, long-term operational stability, and integration into real-world devices. Nevertheless, LCNs are positioned as a versatile platform for next-generation technologies in soft robotics, adaptive optics, and advanced membrane systems.

Triboelectric nanogenerators (TENGs) have emerged as a promising technology for sustainable energy harvesting and health monitoring applications. This study unveils a promising TENG device based on electrospun polyvinylidene fluoride nanofibers (PVDF NF) incorporated with 2D nanofillers, MXene (Ti₃C₂T_x) synthesized by HF etching, hexagonal boron nitride nanosheets (hBNNs) synthesized by liquid phase exfoliation method, and reduced graphene oxide (rGO). The structural, morphological, and spectroscopic characterization confirms successful integration of these nanomaterials within the PVDF matrix. Utilizing these materials, the TENG device is assembled and optimized through triboelectric layer and substrate variations, which reveals a standout combination: PVDF-MXene/indium tin oxide-coated polyethylene terephthalate (ITO-PET) paired with polydimethylsiloxane (PDMS), achieving superior electrical outputs Voc = 80 V, current density = 250 nA cm⁻², charge density = 5 nC cm⁻², and power density = 22 mW m⁻² at 6 MΩ. Along with that, a pressure sensor prototype is also fabricated which demonstrates force dependent sensitivity. Furthermore, the real-time monitoring of wrist pulse pressure sensing demonstrates a subtle increase in current density output up to 2 and 14 nA cm⁻² for deep breathing and running conditions. The present study provides a foundational framework for next-generation energy harvesting devices and self-powered wearable sensors for health monitoring.

One key challenge preventing commercially viable domestic recycling lies in the gap between the high costs of the recycling process and the limited value of recycled raw materials. While additive manufacturing (AM) has the potential to narrow such a gap by converting waste materials into value-added products through the remanufacturing process, the ink formulation for waste materials remains a formidable task due to poor processability. In contrast to high-temperature metallurgy (1000–2000 K), a facile approach is developed to convert waste metals (e.g., stainless steel machining chips) into printable and stable inks for 3D-printed electronics at near room temperature. Moreover, the binder chemistry and percolation mechanism are studied, enabling sustainable ink formulation with non-toxic solvents and environmentally benign polymers (i.e., no fluorinated polymer). The ink formulation is generalizable for various functional materials, including other metals, carbons, and clays. As a proof of concept, a 3D-printed strain sensor from recycled stainless steel (SS) chips is demonstrated, which is shown to effectively identify even minor strains from the human body, highlighting potential wearable applications.

Tissue biopsy is essential for obtaining samples for diagnosis in gastrointestinal (GI) diseases such as inflammatory bowel disease, ulcers, and cancer. However, conventional endoscopic tools often struggle to access confined and tortuous regions, including the small intestine and upper colon. While capsule devices offer improved navigation to these hard-to-reach areas, their biopsy mechanisms carry a relatively high risk of accidental tissue damage. To address this challenge, a magnetically actuated capsule device equipped with a magnetic biopsy unit and an integrated sensing module is proposed for safety-enhanced biopsy. The magnetic biopsy unit incorporates a foldable linkage and dual magnets that provide a magnetic attraction-based safety mechanism to prevent unintentional activation during locomotion. The sensing unit, composed of flexible sensors, enables real-time detection of penetration displacement, allowing for controlled, on-demand tissue sampling. Retrieving tissues are demonstrated safely from targeted GI tract regions, validating the system's efficacy. A sensor array is also seamlessly integrated to continuously track the capsule's position and orientation, ensuring accurate localization throughout the procedure. Therefore, the proposed sensory capsule device, together with the magnetic actuation and tracking system, offers a promising solution for safe, minimally invasive tissue biopsy in the complex and constrained regions of the GI tract.

Laser Scribed Graphene (LSG) technique offers mask-free, binder-free patterning of porous, 3D interconnected graphene, ideal for biomedical device development. Laser power during LSG fabrication directly influences material quality and properties. In this study, spectroscopic, surface morphology, and Brunauer-Emmet-Teller analyses are performed to evaluate the characteristics of LSG, fabricated on a polyimide sheet at various power levels. To maintain structural integrity and reduce passivation steps, a simple paper disc is interfaced with the LSG electrodes for electrochemical kinetics and sensing studies. The paper interface LSG (P-LSG) electrodes demonstrated significant electrocatalytic activity for bilirubin, assessed by differential pulse voltammetry. Interestingly, P-LSG sensor for bilirubin detection exhibits distinct behaviour in PBS, showing linearity from 2.50 to 750 µM with a limit of detection (LOD) of 1.26 µM, while in serum, it demonstrates linearity from 1.0 to 500 µM and has a lower LOD of 0.49 µM. Additionally, sensitivity is found to be twice as high in serum. The results are validated using UV spectrophotometry, showing that the differences in recovery are less than 14%. The P-LSG electrode significantly reduces fluid requirements to 20 µL. This miniaturized paper interface platform shows strong potential for analyte detection, particularly for small samples such as sweat, tears, and pediatric specimens.

To alleviate the cavity dependence of Helmholtz resonators, this work designs a Helmholtz resonator incorporating porous materials, cover plates, multilayer embedded necks, and cavities, inspired by the structural configuration of tree canopies, trunks, roots, and soil. The sound absorption characteristics and underlying physical mechanisms of the structure are elucidated through impedance matching theory and finite element simulations. The results demonstrate that the introduction of multilayer thin walls induces a velocity modulation phenomenon of sound waves at the necks, causing the surface acoustic impedance and energy dissipation characteristics of the Helmholtz resonator to vary with the number and arrangement of the thin walls. A sound-absorbing acoustic metamaterial composed of tree-inspired bionic Helmholtz resonators, along with two sound-absorbing arrays composed of conventional Helmholtz resonators, is designed. Experimental results show good agreement with both theoretical predictions and simulation outcomes. Compared with the traditional Helmholtz resonator array, the proposed sound-absorbing metamaterial achieves effective absorption within the range of 230–424 Hz, with a nearly 50% reduction in maximum neck length, thereby mitigating the constraint of cavity thickness on neck design and improving the scalability of low-frequency sound absorption. This work provides a strategy for the design of deep subwavelength low-frequency absorbers.

This work introduces a novel approach to laser-engraved electrochemical sensors by exploring vectorized CO₂ laser engraving. Vectorized engraving reduces the interaction between the laser and the precursor material, decreasing uneven carbonization and enhancing charge transfer kinetics. The vectorized engraved patterns allow control over mass transport regimes. The final optimized electrode layout is a spiral, mimicking a disk electrode. Experimental and simulated evaluations have shown that diffusion can be modulated by adjusting the spiral spacing of the lines, leading to radial or planar diffusion. Comparative studies reveal that vector-engraved electrodes outperform raster-mode devices in current density (271 vs. 115–175 µA cm⁻²) and closely match commercial platinum electrodes (deviation 〈7%). Proof-of-concept detection of levofloxacin confirms improved sensitivity without the need for post-fabrication treatments. Interestingly, the interdigitated electrodes incorporate the tunable mass transport features of the vectorized engraving method into numerical simulations to predict and optimize electrode design and electrochemical performance. This work establishes an alternative pathway for developing versatile, next-generation sensor platforms, overcoming the limitations of traditional laser engraving protocols.