Fabrication Of Nanostructures Research Articles

Nanoscale Si fishbone structures for manipulating heat transport using phononic resonators for thermoelectric applications

Thermoelectric materials have the potential to convert waste heat into electricity, but their thermoelectric efficiency must be improved before they are effective and economically viable. One promising route to improving thermoelectric efficiency in thin-film thermoelectric materials is to reduce the material’s thermal conductivity through nanopatterning the surface. In this work nanoscale phononic resonators are introduced to the surface, and their potential to reduce thermal conductivity is explored via coupled experimental and theoretical techniques. Atomistic modelling is used to predict the dependence of the thermal conductivity on different design parameters and used to guide the design and fabrication of silicon fishbone nanostructures. The nanostructure design incorporates a variation on design parameters such as barb length, width and spacing along the shaft length to enable correlation with changes in thermal conductivity. The thermal characteristics of the nanostructures are investigated experimentally using the spatial resolution of scanning thermal microscopy to correlate changes in thermal conductivity with the changes in the structure parameters. The method developed uses a microheater to establish a temperature gradient along the structure which will be affected by any local variations in thermal conductivity. The impact on the thermal gradient and consequently on the tip temperature is modelled using finite element computer simulations. Experimental changes as small as 7.5% are shown to be detectable in this way. Despite the experimental technique being shown to be able to detect thermal changes far smaller than those predicted by the modelling, no modifications of the thermal conductivity are detected. It is concluded that in order to realise the effects of phononic resonators to reduce thermal conductivity, that much smaller structures with a greater ratio of resonator to shaft will be needed.

Construction of Three-Dimensional Dendritic Hierarchically Porous Metal-Organic Framework Nanoarchitectures via Noncentrosymmetric Pore-Induced Anisotropic Assembly.

As a unique class of modular nanomaterials, metal-organic framework (MOF) nanoparticles have attracted widespread interest for use in various fields because of their diverse chemical functionalities, intrinsic microporosity, and three-dimensional (3D) nanoarchitectures. However, endowing MOF nanomaterials with precisely controlled structural symmetries and hierarchical macro/mesoporosities remains a formidable challenge for the researchers. Herein, we report a facile noncentrosymmetric pore-induced anisotropic assembly strategy to prepare a series of 3D dendritic MOF (UiO-66) nanomaterials with highly controllable structural symmetries and hierarchical macro/meso/microporosities. The synthetic route of these nanomaterials depends on the anisotropic nucleation of MOF spherical nanocones with noncentrosymmetric center-radial channels and their oriented growth to isotropic nanospheres through a continuous increase in radius and solid angle. This strategy enables the controllable fabrication of asymmetric MOF nanostructures with abundant geometries and porous structures by regulating the concentration of amphiphilic triblock copolymer templates. Furthermore, the average pore diameter of the resultant MOF nanospheres can be systematically manipulated in a wide range from 35 to 130 nm by finely tuning the reaction temperature. Meanwhile, the strategy can also be extended to synthesize other MOF nanoparticles with similar architectures. Compared with microporous UiO-66 nanocrystals, the MOF nanoparticles with controllable structural symmetries and macro/meso/microporosities show enhanced catalytic activity in the CO2 cycloaddition reaction. The methodology provides new insights into the rational construction of sophisticated asymmetric open nanostructures of hierarchically porous MOFs for many potential applications.

Accelerating Cellulose Nanocrystal Assembly into Chiral Nanostructures.

Cellulose nanocrystal (CNC) suspensions self-assembled into chiral nematic liquid crystals. This property has enabled the development of versatile optical materials with fascinating properties. Nevertheless, the scale-up production and commercial success of chiral nematic CNC superstructures face significant challenges. Fabrication of chiral nematic CNC nanostructures suffers from a ubiquitous pernicious trade-off between uniform chiral nematic structure and rapid self-assembly. Specifically, the chiral nematic assembly of CNCs is a time-consuming, spontaneous process that involves the organization of particles into ordered nanostructures as the solvent evaporates. This review is driven by the interest in accelerating chiral nematic CNC assembly and promoting a long-range oriented chiral nematic CNC superstructure. To start this review, the chirality origins of CNC and CNC aggregates are analyzed. This is followed by a summary of the recent advances in stimuli-accelerated chiral nematic CNC self-assembly procedures, including evaporation-induced self-assembly, continuous coating, vacuum-assisted self-assembly, and shear-induced CNC assembly under confinement. In particular, stimuli-induced unwinding, alignment, and relaxation of chiral nematic structures were highlighted, offering a significant link between the accelerated assembly approaches and uniform chiral nematic nanostructures. Ultimately, future opportunities and challenges for rapid chiral nematic CNC assembly are discussed for more innovative and exciting applications.

Sonochemical synthesis and characterization of Sm2CuO4 nanostructures and their application as visible-light photocatalyst for degradation of water-soluble organic pollutants

In recent years, water contamination has become a significant crisis, and it is crucial to find new materials that can efficiently eliminate these contaminants. The current work presents the Sm2CuO4 nanophotocatalyst for the decolorization of different water-soluble organic contaminants. The fabrication of Sm2CuO4 nanostructures was achieved using a simple and rapid sonochemical pathway, resulting in an optical bandgap of 1.62 eV as determined by diffuse reflectance spectroscopy. Several factors, including different organic contaminants, organic contaminant concentrations, Sm2CuO4 dosages, and the pH of the media, were scrutinized to achieve the best efficiency. The results manifested that Sm2CuO4 was highly effective in removing different organic contaminants from water. For example, when 30 mg of Sm2CuO4 was used with 20 mg L−1 methyl orange under visible irradiation for 100 min, 91.4% of the methyl orange was destroyed. Further investigation revealed that holes (h+) were primarily responsible for pollutant photodegradation when using Sm2CuO4 as a photocatalyst. This finding suggests that Sm2CuO4 could be an excellent candidate for developing new materials to effectively remove water contaminants.

Fabrication of transparent TiO2-GO nanocomposites deposited on vertically aligned ZnO nanowire arrays as hybrid nanostructured photo-anode for dye-sensitized solar cells

In this article, we report the fabrication of hybrid nanostructures comprised of vertically aligned Zinc Oxide (ZnO) nanowires (NWs) coated with titanium dioxide-graphene oxide (TiO2-GO) nanocomposites by easy, cost-effective, chemical method and demonstrate their utilization as photo-anode for dye-sensitized solar cells (DSSCs). A thin layer of transparent TiO2 with varying GO amount is deposited on top of vertical ZnO NW arrays by sol-gel spin coating method. A conventional DSSC structure is fabricated by using hybrid structure as photo-anode, ruthenium based N3 dye as photosensitizers, iodine solution (I−/I3+) as electrolyte and fluorine-doped tin oxide (FTO) coated glass substrate as counter electrode. The fabricated hybrid nanostructure based DSSC exhibits enhanced power conversion efficiency (η) compared to that of pristine ZnO NW photo-anode. Also, other characteristic parameters of DSSCs like open-circuit voltage (Voc), short-circuit current density (Jsc) and fill factor (FF) are estimated from the current density-voltage (J-V) relation measured under illumination of 1 sun (100 mW/cm2) solar spectrum for ZnO NW/TiO2-GO hybrid nanostructures. Improvement in these obtained parameters is observed with increasing GO amount in the TiO2-GO nanocomposite layers deposited on top of ZnO NW arrays. Best performance is delivered by the hybrid nanostructure consists of ZnO NW/TiO2-GO (10%)with optimized value of η ∼0.72% along with Voc ∼491 mV, Jsc ∼2.19 mA/cm2 and FF ∼0.66. This betterment in performance is attributed to the combined effects of improvement in charge transport through the axis of ZnO NWs, increment in contact area and modulation of conductivity of TiO2 by inclusion of conducting GO network. The modulation in charge transport properties of hybrid nanostructures with varying GO amount is studied by complex impedance spectroscopic analyses. The study indicates that particular amount of GO significantly modifies the interfacial effects in fabricated hybrid nanostructures to facilitate better charge transportation.

A dual fragment triggered DNA ladder nanostructure based on logic gate and dispersion-to-localization catalytic hairpin assembly for efficient fluorescence assay of SARS-CoV-2 and H1N1

DNA nanotechnology has been widely utilized in the construction of various functional nanostructures. However, most DNA nanostructures have the shortcomings of low response rate and serious background leakage. Herein, we proposed the conception of AND logic gate cascaded dispersion-to-localization catalytic hairpin assembly (AND gate-DLCHA) for the fabrication of novel DNA ladder nanostructures. In our design, the entropy-driven AND logic gate can precisely recognize two fragments of the target nucleic acid sequences. After AND logic gate activation by target nucleic acids, dispersion-to-localization catalytic hairpin assembly was initiated. Consequently, tremendous DNA ladder nanostructures were generated and the response signal was rapidly enhanced, which can be used for rapid and amplied detection of nucleic acids. Taking advantage of the sensitivity and specificity of AND gate-DLCHA strategy, the fluorescence sensors were established and successfully applied in ultrasensitive assay of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus (H1N1) within 45 min with the limit of detection (LOD) as low as 66 copies mL−1 (SARS-CoV-2) and 33 copies mL−1 (H1N1), which showed perspectives in pathogen identification and biomedical application. The high selectivity and reliability of established sensors was attributed to the dual-fragment analysis. Meanwhile, the sensors possessed minimal leakage and greatly enhanced signal to background (S/B) ratio owing to substrate transduction from dispersion into colocalization. This rationally developed logic gate cascaded dispersion-to-localization catalytic hairpin assembly strategy presented a new approach for the development of DNA nanostructures.

Facile fabrication of ZrV2O7 nanostructures as an electrode material for supercapacitors

Energy depletion is an unavoidable reality in the twenty-first century because of the expansion of energy demands and population. In the past few decades extensive research is being focused on fabrication of novel high-performance active electrode materials for green energy storage devices. In the present work, zirconium vanadate (ZrV2O7) prepared by simple chemical route was proved to be the potential electrode material for supercapacitors (SCs). The synthesized material was analysed using different spectral as well as analytical studies. The pseudocapacitance of ZrV2O7 was evaluated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and Electrochemical Impedance in an alkaline medium. ZrV2O7 delivered substantial specific capacitance (Cs) of 679 F g-1 at 5 mVs-1 and demonstrated a superior long-term cyclic stability, with Cs retention of 92.5% even after 3000 GCD cycles with 87% of coulombic efficiency. These findings substantiate the suitability of ZrV2O7 as alternate material for energy storage systems.

Hybrid metrology for nanometric energy harvesting devices

The parametrization of the nanostructures covering the energy harvesting (EH) devices play an important role in maximizing the exploitation of light and so does the selection of the best suitable fabrication and measurement methods. The fabrication and optical inspection of periodic cylindrical nanostructures for EH devices is a challenging task for both manufacturers and metrologists. In this paper we present the fabrication process of nanowires (NWs) along with optical and non-optical measurement techniques which were used to measure the geometrical parameters of these periodic nanostructures. The paper explains the benefits of hybrid metrology that combine data from different metrology tools to obtain more accurate dimensional information about the measured NW samples than those which can be achieved by using only one metrology instrument and thereby improve the fabrication process. Measurement procedure and the determination of geometrical parameters achieved with uncertainties down to 2 nm are provided in the paper and discussed in detail.

Gold-coated nanoripples produced by UV-Femtosecond lasers for surface enhanced Raman spectroscopy

Femtosecond (fs) lasers have been recognized as a powerful tool for micro/nanofabrication, due to their advantages of high flexibility, high repeatability, and minimal introduction of heat. Many studies have been made to employ fs laser processing in fabrication of nanostructures on substrates for surface-enhanced Raman spectroscopy (SERS). However, there have been few reports of ultraviolet (UV)-fs-laser-induced nanoripples for SERS experiments. In this study, we developed simple, easy-to-prepare, and large-active-area SERS substrates using UV-fs laser irradiation. Nanoripples induced in open air by the UV-fs laser on Silicon (Si) substrates with gold coatings were used as SERS-active substrates. Nanoripple evolution by the UV-fs laser was explored to establish the processing windows for nanoripple formation as functions of laser fluence and hatching distances. Moreover, SERS enhancement factors (EFs) were correlated with the laser induced nanoripple patterns. SERS EFs up to 2.4 × 107 were achieved for Rhodamine 6G (R6G) molecules on the laser-textured Si substrates with Au coatings of 34 nm thick. The average period of nanoripples for the highest SERS EF is 253 nm, fabricated by a laser fluence of 0.48 J/cm2 and a hatching distance of 38 µm. R6G concentration down to 10−9 mol/L was detected on the laser-textured Si substrate. Besides Si substrates, three other materials, stainless steel, glass, and polystyrene, were also investigated for nanoripple formation and SERS measurements. Nanoripple structures were formed on stainless-steel surfaces and the highest SERS EF of 1.5 × 107 was achieved. For glass and polystyrene substrates, no nanoripple structures were found. As a result, the SERS EFs (∼106) of glass and polystyrene are one order of magnitude lower than those of the Si and stainless-steel substrates. The SERS demonstration using these materials further supports the mechanisms of nanoripple formation and provides a foundation to make UV-fs laser processing an effective technique for SERS applications using various materials. Applications for Sudan I, small extracellular vesicles (sEVs), and glucose were explored and demonstrated the capability of the SERS substrates.

Assembling Surface Molecular Sierpiński Triangle Fractals via K+-Invoked Electrostatic Interaction.

Molecular Sierpiński triangles (STs), a family of elegant and well-known fractals, can be prepared on surfaces with atomic precision. Up to date, several kinds of intermolecular interactions such as hydrogen bond, halogen bond, coordination, and even covalent bond have been employed to construct molecular STs on metal surfaces. Herein a series of defect-free molecular STs have been fabricated via electrostatic attraction between potassium cations and electronically polarized chlorine atoms in 4,4″-dichloro-1,1':3',1″-terphenyl (DCTP) molecules on Cu(111) and Ag(111). The electrostatic interaction is confirmed both experimentally by scanning tunneling microscopy and theoretically by density functional theory calculations. These findings illustrate that electrostatic interaction can serve as an efficient driving force to construct molecular fractals, which enriches our toolbox for the bottom-up fabrication of complex functional supramolecular nanostructures.

Fabrication of ZnO Nanostructures Doped with Nb at Different Concentration as a Argon Sensor

This works presents the report on the study of ZnO nanoparticles doped on silicon substrate. ZnO nanoparticles doped was prepared by using thermal immersion method with varies percentage ratio mass of dopant, Niobium. ZnO nanoparticles was characterized for their morphology by using field emission scanning electron microscopy (FESEM), crystalline graphic of material by x-ray diffraction (XRD) and electrical properties by IV measurement. The FESEM results showed that the randomly rougher distribution of ZnO nanoparticles doped with Nb covering on Si surface. XRD results reveals that ZnO nanoparticles doped with Nb was successfully growth on the silicon substrate. IV measurement was measured by 2-point probes. The measurement of the IV was done before and after sample exposed into argon gas. The argon gas was exposed for 10 minutes to indicate the sensitivity of the sample. The result shows that the sample that doped with 10wt% of niobium was the best sample to indicate the performance of the sensor compare to the other sample as observed in the 88.40% response when exposed to Argon gas.

Active Probe Atomic Force Microscopy with Quattro-Parallel Cantilever Arrays for High-Throughput Large-Scale Sample Inspection.

An Atomic Force Microscope(AFM) isa powerful and versatile tool for nanoscale surface studies to capture 3D topography images of samples. However, due to their limited imaging throughput, AFMs have not been widely adopted for large-scale inspection purposes. Researchers have developed high-speed AFM systems to record dynamic process videos in chemical and biological reactions at tens of frames per second, at the cost of a small imaging area of up to several square micrometers. In contrast, inspecting large-scale nanofabricated structures, such as semiconductor wafers, requires nanoscale spatial resolution imaging of a static sample over hundreds of square centimeters with high productivity. Conventional AFMs use a single passive cantilever probe with an optical beam deflection system, which can only collect one pixel at a time during AFM imaging, resulting in low imaging throughput. This work utilizes an array of active cantilevers with embedded piezoresistive sensors and thermomechanical actuators, which allows simultaneous multi-cantilever operation in parallel operation for increased imaging throughput. When combined with large-range nano-positioners and proper control algorithms, each cantilever can be individually controlled to capture multiple AFM images. With data-driven post-processing algorithms, the images can be stitched together, and defect detection can be performed by comparing them to the desired geometry. This paper introduces principles of the custom AFM using the active cantilever arrays, followed by a discussion on practical experiment considerations for inspection applications. Selected example images of silicon calibration grating, highly-oriented pyrolytic graphite, and extreme ultraviolet lithography masks are captured using an array of four active cantilevers ("Quattro") with a 125 µm tip separation distance. With more engineering integration, this high-throughput, large-scale imaging tool can provide 3D metrological data for extreme ultraviolet (EUV) masks, chemical mechanical planarization (CMP) inspection, failure analysis, displays, thin-film step measurements, roughness measurement dies, and laser-engraved dry gas seal grooves.

From Layer-by-Layer Growth to Nanoridge Formation: Selective Area Epitaxy of GaAs by MOVPE.

Selective area epitaxy at the nanoscale enables fabrication of high-quality nanostructures in regular arrays with predefined geometry. Here, we investigate the growth mechanisms of GaAs nanoridges on GaAs (100) substrates in selective area trenches by metal-organic vapor-phase epitaxy (MOVPE). It is found that pre-growth annealing results in the formation of valley-like structures of GaAs with atomic terraces inside the trenches. MOVPE growth of GaAs nanoridges consists of three distinct stages. Filling the trench in the first stage exhibits a step-flow growth behavior. Once the structure grows above the mask surface, it enters the second stage of growth by forming {101} side facets as the (100) flat top facet progressively shrinks. In the third stage, the fully formed nanoridge begins to overgrow onto the mask with a significantly reduced growth rate. We develop a kinetic model that accurately describes the width-dependent evolution of the nanoridge morphology through all three stages. MOVPE growth of fully formed nanoridges takes only about 1 min, which is 60 times faster than in our set of molecular beam epitaxy (MBE) experiments reported recently, and with a more regular, triangular cross-sectional geometry defined solely by the {101} facets. In contrast to MBE, no material loss due to Ga adatom diffusion onto the mask surface is observed in MOVPE until the third stage of growth. These results are useful for the fabrication of GaAs nanoridges of different dimensions on the same substrate for various applications and can be extended to other material systems.

Flow-based approach for scalable fabrication of Ag nanostructured substrate as a platform for surface-enhanced Raman scattering

The droplet-based biphasic reaction is an efficient strategy for the fabrication of surface-bound nanostructures. Here, we developed a process of fabricating ordered micro-ring arrays of silver (Ag) nanostructures from surface nanodroplet reaction on a micro-patterned hydrophobic substrate for reproducible detection by surface-enhanced Raman spectroscopy (SERS). Our process consisted of the generation of surface nanodroplet arrays, followed by a biphasic chemical reaction between droplets and the continuous flow of silver nitrate (AgNO3) precursor solution. The parameters in the formation and reaction of the droplet array were well controlled to maintain the uniformity of Ag nanostructures throughout the substrate. By scaling up the process parameters and the size of the microchamber, we were able to produce a SERS substrate with a surface area of ¿60 cm2 in a single run. Such a large area could be sufficient for analyzing more than a thousand samples. We demonstrated the repeatability of SERS measurements using Ag nanostructures by analyzing three environmental (rhodamine 6G, chlorpyrifos, triclosan), a biological (indoxyl sulfate), and a psychoactive drug (tetrahydrocannabinol) compounds. 2D mapping of SERS intensities was also performed for both small and large-scale substrates by collecting data from more than 100 locations on the substrate. Our work demonstrated droplet-based biphasic reaction as a simple approach for the fabrication of SERS substrate with a large area. The technique may help to eliminate the requirement for sophisticated equipment for the fabrication of SERS active substrate.

Enhanced Photocatalytic and Anticancer Activity of Zn-Doped BaTiO3 Nanoparticles Prepared through a Green Approach Using Banana Peel Extract

Perovskite barium titanate (BaTiO3) has received a lot of interest due to its extraordinary dielectric and ferroelectric properties, along with its moderate biocompatibility. Here, we investigated how Zn doping tuned the physicochemical characteristics, photocatalytic activity, and anticancer potential of BaTiO3 nanoparticles synthesized from banana peel extract. XRD, TEM, SEM, EDS, XPS, BET, Raman, and PL were utilized to characterize the as-synthesized pure and Zn (1 and 3 mol%)-doped BaTiO3 nanoparticles. All of the synthesized samples showed evidence of the BaTiO3 tetragonal phase, and the XRD patterns of the Zn-doped BaTiO3 nanoparticles showed the presence of a Zn peak. The particle size of BaTiO3 decreased with increasing levels of Zn doping without morphological changes. After Zn doping, the PL intensity of BaTiO3 decreased, suggesting a lower electron–hole recombination rate. BET analysis found that the surface area of Zn-doped BaTiO3 nanoparticles was higher than that of pure BaTiO3. Under visible irradiation, the photocatalytic activity of pure and Zn-doped BaTiO3 nanoparticles was compared, and a remarkable 85% photocatalytic activity of Zn (3%)-doped BaTiO3 nanoparticles was measured. As a result, Zn-doped BaTiO3 nanoparticles are recognized as excellent photocatalysts for degrading organic pollutants. According to cytotoxicity data, Zn (3%)-doped BaTiO3 nanoparticles display four-fold greater anticancer activity against human lung carcinoma (A549) than pure BaTiO3 nanoparticles. It was also observed that Zn-doped BaTiO3 nanoparticles kill cancer cells by increasing the intracellular level of reactive oxygen species. Furthermore, compared to pure BaTiO3, the Zn-doped BaTiO3 nanostructure showed better cytocompatibility in non-cancerous human lung fibroblasts (IMR90). The Zn-doped BaTiO3 nanoparticles have a reduced particle size, increased surface area, and a lower electron–hole recombination rate, which are highly beneficial for enhanced photocatalytic and anticancer activity. Overall, current data showed that green-fabricated Zn-BaTiO3 nanoparticles have superior photocatalytic and anticancer effects along with improved biocompatibility compared to those of pure BaTiO3. This work underlines the significance of utilizing agricultural waste (e.g., fruit peel) for the fabrication of BaTiO3-based nanostructures, which hold great promise for biomedical and environmental applications.

Preferential crystal orientation etching of GaN nanopillars in Cl2 plasma

The ability to fabricate organized, dense arrays of GaN nanostructures with high aspect ratios is of great interest for improving light extraction and absorption in optoelectronic devices, such as light-emitting diodes (LEDs) and Lasers.However, achieving this requires a patterning method that allows for the fabrication of GaN nanostructures with a controlled final shape and specific crystallographic facets. Our study shows that a top-down approach combining lithography and Cl2-based plasma etching processes offers the possibility of anisotropically transferring a pattern while revealing smooth nonpolar facets.Although GaN etching in Cl2 is driven by ion-enhanced chemical etching mechanisms, the chemical component is very strong, and Cl2 plasma leads to preferential crystallographic orientation etching of GaN. The mechanisms that drive facet formation are very similar to those involved in wet KOH etching. The etching ability of a specific crystallographic plane by chlorine atoms depends on the planar density and the N dangling bonds present on the plane. Predictably, GaN crystallographic planes will be etched in Cl2 plasmas as follows: a-type semipolar > m-type semipolar planes > a nonpolar plane > m polar planes > c polar planes. Crystallographic etching usually reveals the slowest etching planes, meaning the m-planes. However, consistently with the wet mechanisms, our study shows that the final revealed plane in Cl2 plasma will strongly depend on the surface curvature: in concave surfaces, fast-etch facets persist, while in convex surfaces, slow-etch facets persist. Consequently, Cl2 plasma etching of pillars (convex surfaces) will result in a-type facets, while etching of holes (concave surfaces) result in m-type facets.

Anodic Aluminum Oxide Membrane Assisted Extrusion of Polymer Solutions for Hydrogel Formation

AbstractThe potential of polymeric nanostructures obtained by extruding polymer solutions through reusable anodic aluminum oxide (AAO) nanopores for the fabrication of nanostructures is investigated systematically to be able to unveil the potential impact of structure on cell culturing. Thus, nanostructured Na‐alginate and poly(vinyl alcohol) (PVA) polymers as well as blended alginate/PVA hydrogels are fabricated. Na‐alginate and PVA fibers with different dimensions can be obtained. By extruding Na‐alginate solutions into a non‐solvent also networks of uniform nanofibers (diameter <20 nm) are generated. PVA forms agglomerations of nanofibers and nanoparticles with diameter >100 nm. In addition, cell line‐dependent behavior of the cross‐linked PVA/alginate nanofibers is observed, which is characterized by reduced cell adhesion and cluster formation of PaTu 8988t cells on these blend nanofibers compared to normal cell adhesive behavior of NIH 3T3 cells.

Large-area, regular, periodically ordered, and Au-nanoparticle-decorated 1-D BiVO4/WO3 nanorods as photoanodes with enhanced Photoelectrochemical performance

Photoelectrochemical (PEC) water splitting is a promising and sustainable route for the environmentally friendly production of hydrogen. Although the heterojunction of tungsten trioxide (WO3) and bismuth vanadate (BiVO4) has been recognized as a promising photoanode material, it still faces challenges, including inadequate photocurrent density and limited nanostructure fabrication areas. In this study, we present an innovative approach for fabricating periodically-ordered 1D WO3 nanorods using nanoimprint lithography and hydrothermal synthesis, followed by BiVO4 deposition. The resulting periodically-ordered 1D BiVO4/WO3 nanorods distinctly outperform randomly grown nanorods and planar films in both small-scale (2 × 2.5 cm2) and large-scale (6 × 6 cm2) photoanodes, attributed to improved light absorption and facilitated charge transfer. To further enhance PEC performance, the 1D BiVO4/WO3 nanorods were decorated with gold nanoparticles (AuNPs), leading to an additional performance boost due to the plasmonic effect.

The Fabrication of GaN Nanostructures Using Cost-Effective Methods for Application in Water Splitting

The adjustable bandgap, single crystal structure, and strong chemical inertness of GaN materials make them excellent candidates for water splitting applications. The fabrication of GaN nanostructures can enhance their water splitting performance by increasing their surface area, improving photon absorption, and accelerating photocatalytic reactions. Developing cost-effective methods to fabricate GaN nanostructures is crucial to promote the development of GaN-based materials in water splitting applications. In this review, we introduce the main cost-effective techniques for the fabrication of GaN nanostructures and highlight future development directions.

Free-standing nanowire printed surfaces with high variability in substrate selection for boiling heat transfer enhancement

Nanowires (NWs) constitute a promising solution to the overheating of high-heat-load surfaces in multiphase heat transfer. Typical nanostructure fabrication methods such as complex photolithography and metal-assisted chemical etching (MACE) that utilize patterned templates are limited by high manufacturing costs and type of substrate materials. These limitations significantly hinder the industrial applicability of NW structures in high heat flux units. In this study, we first examine the effect of the morphology of Zinc oxide (ZnO) NW printed substrates, fabricated via microcontact printing (µCP) and solution based growing, on the heat transfer characteristics in pool boiling. Unlike advanced photolithography, µCP offers greater variability and convenience in terms of the substrate selection and large area creation for NW fabrication. Compared with the silicon substrate, the underlying mechanisms for enhancing both the critical heat flux and heat transfer coefficient of ZnO NW substrates are explored by analyzing the surface morphology, bubble, and wicking characteristics of the test surfaces, in order to determine the applicability of boiling heat transfer using ZnO NWs in industrial fields.