搜索结果：Beilstein journal of nanotechnology

Compared to bulk solids, defects in low-dimensional materials and, specifically, 2D systems are expected to have a stronger effect, detrimental or beneficial, on their properties. Owing to their geometry, defects in 2D materials can easily be formed due to the interaction with the environment or under impacts of energetic particles, such as ions and electrons. At the same time, many concepts of defect production under irradiation in bulk systems are not applicable for 2D materials or require substantial modifications. Various aspects of the physics and chemistry of defects in 2D materials have been addressed, and the results of these investigations are presented in hundreds of research papers and review articles. However, the challenges and open questions that still remain in the field have received relatively little attention. These topics were recently addressed at the symposium "Defect-mediated engineering of nanomaterials for energy and quantum applications" organized by the Beilstein-Institut. Following the discussions at the symposium, here, we present the challenges and open questions in our understanding of the behavior of defective 2D materials, interaction of energetic particles with low-dimensional targets, and defect-mediated engineering of the properties of 2D systems. We further discuss possible solutions to these problems or suggest "work-arounds", which should accelerate the progress in the field.

In this study, the elastic properties of Cu and (Cu x Ni1- x )3Sn were calculated to reveal the effects of Ni alloying on the interfacial mechanical properties of (Cu x Ni1- x )3Sn/Cu in lead-free solder joints. The results reveal that, within the thermodynamically stable domain of (Cu x Ni1- x )3Sn, the increase of Ni content can enhance the interfacial mechanical properties of (Cu x Ni1- x )3Sn/Cu, and increase the reliability of the lead-free solder joints. The enhancement mechanism can be attributed to the simultaneous improvements of oriented Young's modulus and ductility of (Cu x Ni1- x )3Sn, achieved by Ni alloying. But higher Ni content beyond the thermodynamically stable domain of (Cu x Ni1- x )3Sn will deteriorate the interfacial mechanical properties by mechanical or thermodynamic mechanisms and decrease the reliability of the lead-free solder joints. The results presented in this study will not only unveil the effects of Ni alloying on the interfacial properties of lead-free solder joints, but also will provide a guidance for high-performance lead-free solder design by alloying strategies to meet the requirements for electronic device miniaturization and harsh environmental applications.

This proof-of-concept study evaluated whether semi-solid extrusion (SSE) 3D printing could be used to fabricate multilayer topical films that simultaneously enhance skin bioadhesion and photoprotection of curcumin, a highly photolabile anti-inflammatory and antioxidant compound. The development of topical films for cutaneous delivery faces several challenges, including the need for strong skin adhesion and the protection of photolabile actives from light exposure. We hypothesized that multilayered films designed for the cutaneous delivery of curcumin and produced by SSE could address these limitations. To overcome its poor solubility and enhance bioadhesion, curcumin was encapsulated in polymeric nanocapsules (C-NCs), yielding a mean particle size of 218 ± 5 nm, a polydispersity index of 0.10 ± 0.02, a zeta potential of -11 ± 4 mV, and 100% encapsulation efficiency. Films were fabricated containing either C-NCs (FC-NC) or unloaded curcumin (FC) and consisted of three layers, namely, a chitosan-based bottom layer, a middle layer of carboxymethylcellulose and alginate, and a carboxymethylcellulose top layer incorporating titanium dioxide (TiO2). The lower and intermediate layers contained C-NC or curcumin. The final films (15 × 15 × 1.5 mm) contained 282.20 ± 7.75 µg and 246.80 ± 6.70 µg of curcumin in FC-NC and FC, respectively. Films containing the bottom chitosan layer exhibited the highest bioadhesion, while the presence of a TiO2 top layer effectively prevented UVC-induced photodegradation, supporting our hypothesis. Furthermore, the presence of C-NCs in FC-NC films promoted higher bioadhesion. This proof-of-concept study demonstrates the feasibility of integrating nanocarriers with 3D printing technology to engineer multilayer polymeric films for cutaneous application, offering enhanced bioadhesion and photoprotection. This work demonstrates how additive manufacturing can be used to design hierarchically structured, nanocarrier-integrated systems with spatially resolved functionalities.

This study reports the design and synthesis of a C 3-symmetric discotic tetrathiafulvalene (TTF) derivative, MeS-TTF-Ts, as a molecular platform for the self-assembly of one-dimensional conductive nanostructures. The molecular architecture contains three TTF units radially arranged around a rigid C 3-symmetric core, enabling the formation of highly ordered one-dimensional assemblies through cooperative π-π stacking and directional intermolecular interactions. Solution casting of MeS-TTF-Ts produced nanorod and nanofiber structures with morphologies strongly dependent on the solvent conditions. AFM and SEM observations revealed that distinct supramolecular structures were formed depending on the solvent and substrate used, suggesting that molecular interactions and assembly processes play important roles in determining the resulting morphologies. Furthermore, MeS-TTF-Ts was combined with the strong electron acceptor F4TCNQ to form a charge-transfer complex, (MeS-TTF-Ts)(F4TCNQ)3, which yielded well-defined one-dimensional nanofibers. UV-vis and FTIR spectroscopic analyses confirmed substantial charge transfer from MeS-TTF-Ts to F4TCNQ through the formation of F4TCNQ- and TTF+ species. These results indicate the formation of a highly charge-transferred donor-acceptor assembly in the nanofibers. Electrical conductivity measurements revealed that the (MeS-TTF-Ts)(F4TCNQ)3 nanofibers exhibit a conductivity of 1.24 × 10-2 S·cm-1. These findings demonstrate that rational molecular design combined with controlled supramolecular self-assembly provides an effective strategy for constructing one-dimensional conductive nanostructures based on organic charge-transfer systems.

Wood tracheids and fibers exhibit diverse structures and shapes across plant species. The hierarchical structure and composition of cellulose, hemicelluloses, and lignin enables wood to withstand high stress. This structural resilience makes wood a versatile material for applications ranging from construction to advanced composites. However, a detailed understanding of how delignification affects softwood tracheid and hardwood fiber morphology is crucial for predicting material behavior and developing modified wood products. This study investigated the overall structural changes due to delignification, in five wood species, namely, spruce, beech, balsa, Douglas fir, and poplar. It additionally provides detailed morphology of delignified single tracheids and fibers. Scanning electron microscopy was used to compare the morphology between untreated and delignified fibers and tracheids. X-ray tomography enabled us to reconstruct high-resolution 3D models of delignified single tracheids or fibers, providing information on the pit arrangements. Moreover, delignification resulted in facilitated separation of fibers and tracheids and frayed wall appearance. We observed similar tracheid/fiber diameters and wall thicknesses for all five wood species. These findings enhance our understanding of the wood fiber and tracheid structures across species and the effects of delignification. The 3D models provide a valuable resource for (1) understanding interspecies differences of fibers and tracheids, (2) optimizing the use of delignified wood in industrial applications (including bio-based and bio-inspired materials), and (3) physical modeling of wood regarding questions of wood biomechanics and water management.

A heavy-atom-free and non-toxic spirocyclic C-BODIPY singlet oxygen photosensitizer was successfully incorporated into electrospun polymeric nanofibers. Optimization of the material composition revealed that polycaprolactone (PCL), an FDA- and EMA-approved, biodegradable, easily accessible, and cost-efficient polymer, doped with BODIPY at a concentration of only 0.15 wt %, is an efficient photocatalyst for the degradation of the pharmaceutical agents ranitidine, propranolol, and cimetidine, selected as model water pollutants. The obtained nanofibers showed smooth and uniform morphology along with very high durability and resistance toward oxidation, remaining active even after 20 reaction cycles. EDX, ToF-SIMS and XPS analyses confirmed the homogenous distribution of BODIPY within the polymeric matrix. Furthermore, the materials showed significant photoinactivation of Staphylococcus aureus under white light irradiation compared to the control experiment performed without irradiation. These findings highlight the potential of the electrospun PCL nanofibers as optimal matrix for the immobilization with singlet oxygen photosensitizers and subsequent application in the decontamination of water from pollutants and pathogens.

Nanotechnology is revolutionizing different sectors such as medicine, energy, defence, and environmental science by enabling the development of materials and technologies with exceptional precision and efficiency. From advanced drug delivery systems to clean energy solutions, the applications of nanotechnology are diverse and transformative. However, these innovations are accompanied by complex challenges regarding safety and sustainability for both the nanoscale materials themselves and for the products containing them. The growing complexity of engineered nanomaterials calls for proactive strategies to mitigate potential risks while maintaining their functional benefits. The "Safe and Sustainable by Design" (SSbD) concept addresses these challenges by embedding safety measures and sustainability considerations into the earliest stages of material development. Advances in machine learning (ML) and artificial intelligence (AI) have further enhanced the effectiveness of SSbD by providing predictive modelling, risk assessment, decision-making tools, and the ability to computationally screen candidate materials before producing them. This perspective article highlights how ML and AI are driving the evolution of SSbD in nanotechnology, focussing on predictive toxicology, materials informatics, lifecycle analysis, and the pivotal role of digital twins. It also explores current challenges, emerging opportunities, and the path forward for integrating ML/AI-driven SSbD frameworks into regulatory and industrial practices.

Epithelial tissues form selective barriers essential for physiological homeostasis. Conventional in vitro models rely on solid substrates, which limit the physicochemical flexibility of the cellular microenvironment. Here, we introduce a microfluidic platform in which a collagen-coated liquid-liquid interface formed between perfluorocarbon (FC-43) and culture medium serves as a substrate for epithelial cell adhesion. By culturing Caco-2 cells in the device, we show that the liquid interface supports cell attachment and the formation of monolayers. Immunofluorescence observation reveals the development of tight junctions and organized actin cytoskeletons, indicating early-stage epithelial maturation. Our new microfluidic system enables the formation of stable liquid-liquid interfaces that serve as viable and flexible substrates for epithelial cell culture, offering new opportunities for multiphase microfluidic models of epithelial barriers.

Co-doped titanium dioxide materials were successfully synthesized by the sol-gel method. Molybdenum was incorporated into all materials at 0.5 wt %, while the co-dopants, copper and cobalt, were added at 0.2-0.5 wt %. The co-doped TiO2 photocatalysts were characterized by XRD, SEM, N2 physisorption, UV-vis diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The structural characterization showed stabilization of the anatase phase, and lattice distortion was evidenced after dopant incorporation into the TiO2 structure. Morphological characterization showed poorly defined spherical particles that decreased in size with increasing Cu and Co concentrations. PL spectra showed an additional signal attributed to the ability of the metal dopants to capture electrons. The point of zero charge of the photocatalytic systems TiO2, Cu-Mo/TiO2, and Co-Mo/TiO2 was evaluated and reported. Materials with lower concentrations of the co-dopants Cu and Co were more efficient at degrading ketoprofen. The most efficient photocatalyst was 0.2 Cu-0.5 Mo/TiO2, which achieved the complete degradation of ketoprofen and 90% of mineralization. It was determined that HO· radicals play an important role in the oxidation reactions.

The incorporation of copper and oxygen into zinc telluride (ZnTe) thin films deposited by radio-frequency magnetron sputtering from a single ZnTe-CuO composite target was investigated. The nominal Cu and O concentrations ranged from 3 to 13 atom %, and films were grown at substrate temperatures of 300 and 350 °C. Energy-dispersive X-ray spectroscopy confirmed controlled compositional transfer from the target to the films. X-ray diffraction analysis revealed that all films are polycrystalline, exhibiting a coexistence of zinc blende and wurtzite ZnTe phases. Low dopant concentrations produced only minor lattice modifications, while higher Cu and O contents promoted the formation of Cu2- x Te secondary phases, as confirmed by Raman spectroscopy, grazing-incidence X-ray diffraction and scanning electron microscopy. Optical measurements showed a significant reduction in infrared transmittance with increasing Cu concentration, attributed to the metallic-like absorption of Cu2- x Te phases. Electrical characterization revealed a transition from semiconducting to highly conductive behavior with resistivity decreasing from approximately 102 to 10-2 Ω·cm for films grown at 300 °C and from 101 to 10-3 Ω·cm for films grown at 350 °C. Simultaneously, the carrier concentration increased from approximately 1017 to 1021 cm-3 and the mobility from 10-1 to 101 cm2·V-1·s-1. These results indicate that structural, optical, and electrical properties of ZnTe are primarily influenced by Cu incorporation and the formation of conductive Cu-rich secondary phases, yielding a biphasic system composed of semiconducting ZnTe and conductive Cu-rich telluride phases. These material properties suggest potential relevance for future studies of back-contact materials in CdTe-based solar cells.

In this work, the high-frequency response of a multiwalled carbon nanotube (MWCNT) film grown on a silicon substrate is compared with that of MWCNT sponges (CNSs). Different from the CNT film, CNSs are a self-standing material that can operate in the absence of a supporting substrate, showing high flexibility, light weight, and mechanical robustness. We tested our synthesized CNSs as active material for the production of antennas working in the radio frequency (RF) range to determine whether CNT sponges present, in addition to practical advantages over CNT films, also an actual performance gain. The antenna built from CNSs shows an enhanced response gain compared with that of the MWCNT film, with both antennas having a maximum positioned around 4.8 GHz. After identifying the best CNT-based sample, the experiment focused on improving the CNS antenna's response. In particular, we observed that the response of S 11 = -22.6 dB around 4.8 GHz from the CNS antenna improved after a mild treatment with ethanol, reaching S11 = -32.6 dB measured after 10 min of waiting. This observed effect is studied in detail with scanning electron microscopy and Raman spectroscopy, which point to significant modifications of the CNS's inner morphology after the treatment. Signal reception tests simulating real-world operation conditions were also carried out at two different distances to evaluate the practical application of the CNS as RF antennas. The ethanol treatment was also applied for these tests, and an increase in the response up to 45% was found for the two studied positions.

Poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) exhibits a range of unique physical properties that are critical for its diverse applications in photonics, optoelectronics, memory devices, and sensing technologies. In this study, we investigate the thermochromic behavior of PAZO thin films, focusing on the relationship between the structural organization of the polymer side chains and temperature-induced optical changes. By combining experimental spectroscopic techniques with theoretical modeling, we demonstrate that the thermochromic response of PAZO films is strongly influenced by molecular aggregation, film thickness, and thermal treatment conditions. The observed changes in optical properties suggest that this response is governed by temperature-induced modulation of molecular ordering and aggregation state, which in turn alters the electronic transitions responsible for light absorption. Theoretical calculations further support these findings, indicating that temperature-dependent intermolecular interactions and conformational changes play a significant role in shaping the optical behavior of the films. These results provide new insights into the structure-property relationships underlying thermochromism in azopolymer thin films and offer valuable guidelines for the design of thermally responsive photonic materials.

Silver nanoparticles (AgNPs) possess inherent catalytic, antimicrobial, and optical properties, making them a strong candidate for environmental applications in water, air, and soil. Indeed, various reviews are available, though a significant gap persists in addressing all environmental pollutants. This review comprehensively and critically analyses the advancement in AgNP research spanning from synthesis and characterisation to practical deployment and ecotoxicological assessment. The AgNP-based systems are evaluated regarding antimicrobial disinfection, adsorptive and catalytic/photocatalytic removal of persistent organic pollutants, and integration into antifouling nanofiltration and ultrafiltration membrane technologies used for management of water pollutants. In addition, AgNPs-assisted nanosystems in fibrous filter membranes and photocatalytic composite coatings for the removal of volatile organic compounds, particulate matter, and gaseous pollutants are reviewed. Furthermore, AgNP applications for heavy metal immobilisation, organic pollutant degradation, plant disease management, and growth promotion are assessed alongside their ecotoxicological implications. Besides remediation, environmental monitoring capabilities of AgNP-based sensing platforms are systematically reviewed across five transduction modalities, including colourimetric/UV-vis LSPR, SERS, electrochemical, fluorometric, and gas sensing, covering a broad range of analytes considered as environmental pollutants. Key challenges, including nanoparticle aggregation, long-term colloidal instability, synthesis irreproducibility, ecotoxicological risks arising from Ag+ ion release and environmental persistence, and the current absence of harmonised regulatory frameworks for AgNP deployment, are critically discussed. This review provides a structured, evidence-based foundation for researchers and engineers working toward the responsible, scalable application of AgNP-based technologies to address contemporary environmental challenges.

Nanoparticle synthesis via pulsed laser ablation in liquids has gained prominence as a versatile and environmentally friendly approach for producing ligand-free colloids with controlled composition, size, and morphology. While pulsed laser ablation in liquids offers unparalleled advantages in terms of nanoparticle purity and material versatility, enhancing the size control and productivity require modifications of the standard pulsed laser ablation in liquids technique, such as the incorporation of beam shaping techniques. Recent developments in spatial and temporal beam shaping have demonstrated their potential to revolutionise pulsed laser ablation in liquids by enabling more precise energy deposition and modified nanoparticle production dynamics. This review highlights the critical role of beam shaping, encompassing spatial shaping of the beam to influence laser-material interaction and temporal modification to optimise pulse duration and energy delivery. The current advancements in beam shaping techniques, their impact on the nanoparticle characteristics, and their broader implications for scaling pulsed laser ablation in liquids to meet industrial demands are highlighted, offering a comprehensive perspective on the future of this dynamic field.

Poly(ε-caprolactone) nanocapsules containing breu branco (Protium heptaphyllum) essential oil were successfully prepared by nanoprecipitation and optimized using a Box-Behnken design. Spherical nanosystems were obtained, with a mean particle size of 172.10 ± 0.90 nm, a polydispersity index of 0.14 ± 0.04, a zeta potential of -25.49 ± 1.08 mV and an encapsulation efficiency above 99%, in addition to long-term colloidal stability. Cell viability assays in HaCaT cells showed high biocompatibility, with cell viability above 70% up to 6 mg/mL and only moderate toxicity at 12 mg/mL. In antimicrobial assays, the free oil had no inhibitory effect against Staphylococcus aureus, while the nanocapsules exhibited a minimum inhibitory concentration of 0.55 mg/mL, indicating enhanced antibacterial activity. Wound-healing assays further demonstrated improved keratinocyte migration compared to serum-free controls. Additionally, cytokine profiling by cytometric bead array indicated an anti-inflammatory profile, with strong suppression of IL-6 and selective increases in IL-2, IL-4, and TNF-α at higher doses (6 mg/mL) in nanocapsule-treated fibroblasts. Overall, these findings demonstrate that nanoencapsulation not only stabilizes breu branco essential oil but also enhances its antimicrobial, regenerative, and immunomodulatory effects, while fostering the sustainable valorization of Amazonian biodiversity.

Fabricating microelectronic devices for two-dimensional (2D) materials research is essential but often limited by the high cost and need for specialized facilities. This study establishes a practical method for cleaning and reusing substrates with pre-patterned electrodes. The cleaning protocol involves the use of an ultrasonic bath in warm N-methyl-2-pyrrolidone (NMP), enabling the removal of 2D materials without damaging the electrodes. Electrical measurements, Raman analysis, and Kelvin probe force microscopy measurements collectively confirm the feasibility of repeatedly reusing the same pre-patterned chip, showing that the cleaned regions exhibit no detectable Raman signatures of the transferred 2D material, retain a largely homogeneous surface-potential distribution, and preserve comparable electrical performance after reuse. By extending the lifetime of pre-patterned chips, this approach can reduce substrate consumption and lower the cost of 2D device prototyping.

The performance of perovskite solar cells (PSCs) is primarily governed by the built-in electric field (BEF), which dictates photocarrier separation, drift-diffusion transport, and extraction pathways, thereby shaping critical device parameters such as open-circuit voltage and fill factor. This review highlights recent progress in junction engineering strategies for BEF enhancement. Homojunctions extend interfacial potential fields into the bulk through controlled doping and orientation modulation, thereby suppressing nonradiative recombination and improving carrier extraction. Gradient junctions introduce continuous compositional or bandgap tilts across the film thickness, enabling depth-extended electric fields and improved spatial continuity of charge transport. By contrast, 2D/3D heterojunctions exploit interfacial dipole formation, intrinsic polarization, and phase-penetration effects to amplify and homogenize the BEF, while simultaneously improving energy-level alignment and defect passivation. We systematically compare these strategies within a unified framework of BEF descriptors, magnitude, penetration depth, directionality, and spatial continuity. Special emphasis is placed on the potential for synergistic integration of multiple junction architectures and on the development of mild, process-compatible fabrication routes. Ultimately, optimizing the BEF provides a powerful lever for advancing power conversion efficiency, open-circuit voltage, and long-term operational stability in state-of-the-art PSCs, while avoiding the introduction of parasitic energy barriers.

Dye-based fluorescent organic nanoparticles (dFONs) represent a promising class of bioimaging probes combining high brightness with molecular tunability. While their fluorescence performance is well established for one-photon excitation, their single-particle properties under two-photon excitation remain to be evaluated. Here, we perform a comprehensive optical characterization of two distinct dFONs designed to exhibit the same two-photon brightness but with different photostabilities. Saturation measurements of individual nanoparticles allowed for an estimation of their two-photon absorption cross sections, which were found to be consistent with ensemble values when taking into account a local-field correction. Time-resolved experiments further revealed that nanoparticles with the highest absorption cross section photobleach significantly faster, confirming the trade-off between absorption efficiency and photostability. These results demonstrate that the photophysical behavior of dFONs can be rationally engineered at the molecular level and provide design principles for the development of optimized organic nanoparticles for nonlinear fluorescence microscopy and bioimaging applications.

An electrochemical sensor for the determination of ciprofloxacin (CPR) was developed using a glassy carbon electrode modified with MIL-101/reduced graphene oxide (MIL-101/rGO). MIL-101/rGO was synthesized via a facile ultrasonic-assisted method and characterized by various physicochemical techniques. The synergistic combination of MIL-101 with rGO significantly enhanced the electrocatalytic activity toward CPR oxidation. The electrochemical behavior of CPR on the MIL-101/rGO-modified electrode was systematically investigated using cyclic voltammetry and differential pulse voltammetry. Under optimized experimental conditions, the proposed sensor exhibited a linear response over 0.25-9.41 µM and a detection limit of 0.11 µM for CPR determination. The sensor also demonstrated good selectivity, satisfactory repeatability, and long-term stability. Furthermore, the method's practical applicability was validated by the determination of CPR in pharmaceutical samples, yielding acceptable recoveries. These results indicate that the MIL-101/rGO-modified electrode provides a promising and efficient platform for the electrochemical sensing of CPR in pharmaceutical and environmental analysis.