Atomic-Scale Characterization of Microscale Battery Particles Enabled by a High-Throughput Focused Ion Beam Milling Technique.

The cathode materials in lithium-ion batteries (LIBs) require improvements to address issues such as surface degradation, short-circuiting, and the formation of dendrites. One such method for addressing these issues is using surface coatings. Coatings can be sought to improve the durability of cathode materials, but the characterization of the uniformity and stability of the coating is important to assess the performance and lifetime of these materials.

Electrodeposition of PdPt Nanoparticles on Edges and S-Vacancies in Exfoliated MoS Nanosheets for Enhanced Hydrogen Evolution Activity.

Deposition of metal nanoparticles onto the molybdenum disulfide (MoS) nanosheets is an efficient method to tune the electronic structure of the MoS and maximize its catalytic performance towards the hydrogen evolution reaction (HER). Herein, we report the electrodeposition of Pd and Pt nanoparticles onto desulfurized MoS nanosheets (MoS) to achieve an improved HER activity in an acidic electrolyte. The initial MoS powder was exfoliated and isolated through centrifugation, followed by electrochemical desulfurization to create defect sites.

Near-field enhancement of optical second harmonic generation in hybrid gold-lithium niobate nanostructures.

Nanophotonics research has focused recently on the ability of nonlinear optical processes to mediate and transform optical signals in a myriad of novel devices, including optical modulators, transducers, color filters, photodetectors, photon sources, and ultrafast optical switches. The inherent weakness of optical nonlinearities at smaller scales has, however, hindered the realization of efficient miniaturized devices, and strategies for enhancing both device efficiencies and synthesis throughput via nanoengineering remain limited. Here, we demonstrate a novel mechanism by which second harmonic generation, a prototypical nonlinear optical phenomenon, from individual lithium niobate particles can be significantly enhanced through nonradiative coupling to the localized surface plasmon resonances of embedded gold nanoparticles.

Lithium niobate particles with a tunable diameter and porosity for optical second harmonic generation.

Uniform, porous particles of lithium niobate (LiNbO) can be used as contrast agents in bioimaging, drug delivery carriers, nonlinear optical emitters, biosensors, photocatalysts and electrode materials in lithium-ion batteries. In this article, we introduce a hydrothermal method to prepare uniform, mesoporous LiNbO particles with a tunable diameter and porosity. These properties are each tuned by adjusting the reaction times of the hydrothermal process.

Gold-Protein Composite Nanoparticles for Enhanced X-ray Interactions: A Potential Formulation for Triggered Release.

Drug-delivery vehicles have been used extensively to modulate the biodistribution of drugs for the purpose of maximizing their therapeutic effects while minimizing systemic toxicity. The release characteristics of the vehicle must be balanced with its encapsulation properties to achieve optimal delivery of the drug. An alternative approach is to design a delivery vehicle that preferentially releases its contents under specific endogenous (e.

Contact transfer of engineered nanomaterials in the workplace.

This study investigates the potential spread of cadmium selenide quantum dots in laboratory environments through contact of gloves with simulated dry spills on laboratory countertops. Secondary transfer of quantum dots from the contaminated gloves to other substrates was initiated by contact of the gloves with different materials found in the laboratory. Transfer of quantum dots to these substrates was qualitatively evaluated by inspection under ultraviolet illumination.

Tuning the Surface Chemistry of Second-Harmonic-Active Lithium Niobate Nanoprobes Using a Silanol-Alcohol Condensation Reaction.

The surface functionalization of nanoparticles (NPs) is of great interest for improving the use of NPs in, for example, therapeutic and diagnostic applications. The conjugation of specific molecules with NPs through the formation of covalent linkages is often sought to provide a high degree of colloidal stability and biocompatibility, as well as to provide functional groups for further surface modification. NPs of lithium niobate (LiNbO) have been explored for use in second-harmonic-generation (SHG)-based bioimaging, expanding the applications of SHG-based microscopy techniques.

Elucidating the role of precursors in synthesizing single crystalline lithium niobate nanomaterials: a study of effects of lithium precursors on nanoparticle quality.

A number of solution-based procedures have been realized for the synthesis of lithium niobate (LiNbO3) nanoparticles (NPs). Relatively little is, however, known about the influences of the selection of lithium (Li) precursors on the resulting dimensions, shapes, crystallinity, and purity of the products. A comparative study is provided herein on the role of different Li precursors during the synthesis of LiNbO3 NPs.

Size Fractionation of Titania Nanoparticles in Wild Grown in a Native Environment.

We report a size fractionation of titania (TiO) nanoparticles absorbed from the environment and found within wild plants. The nanoparticles were isolated by extraction and isolation from distinct plant organs, as well as from the corresponding rhizosphere of wild, adult plants. The collected nanoparticles were characterized by scanning transmission electron microscopy coupled with energy dispersive X-ray spectroscopy (STEM-EDS).

Differentiation of Nanoparticles Isolated from Distinct Plant Species Naturally Growing in a Heavy Metal Polluted Site.

Leaves harvested from the plants of two different species (Dittrichia viscosa and Cichorium intybus) grown in their autogenous environment near a steel manufacturing company were characterized for naturally accumulated nanoparticles. These plant species are known to accumulate heavy metals. It was, however, unknown if these species would also accumulate these heavy metals in the form of nanoparticles.

Green solvent assisted synthesis of cesium bismuth halide perovskite nanocrystals and the influences of slow and fast anion exchange rates.

Replacing lead in halide perovskites to address the concerns of their toxicity and stability has driven a recent surge in research toward alternative lead-free perovskite materials. Lead-free all inorganic cesium bismuth halide (CsBiX) perovskite nanocrystals have attracted attention in recent years due to the air-stability and non-toxic nature of bismuth. Herein, we demonstrate a facile sonication-assisted approach for the preparation of all-inorganic cesium bismuth iodide (CsBiI) perovskite nanocrystals (NCs) using propylene carbonate as a green, alternative solvent.

Synthesis and Characterization of Tunable, pH-Responsive Nanoparticle-Microgel Composites for Surface-Enhanced Raman Scattering Detection.

The synthesis of microgels with pH-tunable swelling leads to adjustable and pH-responsive substrates for surface-enhanced Raman scattering (SERS)-active nanoparticles (NPs). Sterically stabilized and cross-linked latexes were synthesized from random copolymers of styrene (S) and 2-vinylpyridine (2VP). The pH-dependent latex-to-microgel transition and swellability were tuned based on their hydrophobic-to-hydrophilic content established by the S/2VP ratio.

Tunable functionalization of silica coated iron oxide nanoparticles achieved through a silanol-alcohol condensation reaction.

The surface properties of nanoparticles play an important role in their interactions with their surroundings. Silane reagents have been used for surface modifications to silica shells on iron oxide nanoparticles, but using these reagents presents some challenges. An alternative approach to modifying the surfaces of these silica shells was developed to impart different terminal functional groups, such as a thiol, alcohol, or carboxylic acid, through the use of alcohol-based reagents.

One-pot synthesis of sub-10 nm LiNbO nanocrystals exhibiting a tunable optical second harmonic response.

Nanophotonics, dealing with the properties of light interacting with nanometer scale materials and structures, has emerged as a sought after platform for sensing and imaging applications, and is impacting fields that include advanced information technology, signal processing circuits, and cryptography. Lithium niobate (LiNbO) is a unique photonic material, often referred to as the "silicon of photonics" due to its excellent optical properties. In this article, we introduce a solution-phase method to prepare single-crystalline LiNbO nanoparticles with average diameters of 7 nm.

Novel defect-fluorite pyrochlore sodium niobate nanoparticles: solution-phase synthesis and radiation tolerance analysis.

Materials possessing a defect-fluorite pyrochlore structure can have a range of useful properties that are sought after, which include their radiation tolerance, nuclear waste immobilization, and phase stability at elevated temperatures. In this study, we demonstrate for the first time the synthesis and a detailed analysis of defect-fluorite pyrochlore sodium niobate (NaNbO3) nanoparticles. This analysis included an investigation into their stability to elevated temperatures and neutron irradiation.

Mesoporous Platinum Prepared by Electrodeposition for Ultralow Loading Proton Exchange Membrane Fuel Cells.

The porosity and utilization of platinum catalysts have a direct impact on their performance within proton exchange membrane fuel cells. It is desirable to identify methods that can prepare these catalysts with the desired features, and that can be widely implemented using existing and industrially scalable techniques. Through the use of electrodeposition processes, fuel cell testing, and electron microscopy analyses before and after fuel cell testing, we report the preparation and performance of mesoporous platinum catalysts for proton exchange membrane fuel cells.

Template assisted preparation of high surface area macroporous supports with uniform and tunable nanocrystal loadings.

The incorporation of catalytic nanocrystals into macroporous support materials has been very attractive due to their increased catalyst mass activity. This increase in catalytic efficiency is attributed in part to the increased surface area to volume ratio of the catalysts and the use of complementary support materials that can enhance their catalytic activity and stability. A uniform and tunable coating of nanocrystals on porous matrices can be difficult to achieve with some techniques such as electrodeposition.

Covalent Surface Modification of Silicon Oxides with Alcohols in Polar Aprotic Solvents.

Alcohol-based monolayers were successfully formed on the surfaces of silicon oxides through reactions performed in polar aprotic solvents. Monolayers prepared from alcohol-based reagents have been previously introduced as an alternative approach to covalently modify the surfaces of silicon oxides. These reagents are readily available, widely distributed, and are minimally susceptible to side reactions with ambient moisture.

Hexagonal Arrays of Cylindrical Nickel Microstructures for Improved Oxygen Evolution Reaction.

Fuel-cell systems are of interest for a wide range of applications, in part for their utility in power generation from nonfossil-fuel sources. However, the generation of these alternative fuels, through electrochemical means, is a relatively inefficient process due to gas passivation of the electrode surfaces. Uniform microstructured nickel surfaces were prepared by photolithographic techniques as a systematic approach to correlating surface morphologies to their performance in the electrochemically driven oxygen evolution reaction (OER) in alkaline media.

Tuning Oleophobicity of Silicon Oxide Surfaces with Mixed Monolayers of Aliphatic and Fluorinated Alcohols.

We demonstrate the formation of mixed monolayers derived from a microwave-assisted reaction of alcohols with silicon oxide surfaces in order to tune their surface oleophobicity. This simple, rapid method provides an opportunity to precisely tune the constituents of the monolayers. As a demonstration, we sought fluorinated alcohols and aliphatic alcohols as reagents to form monolayers from two distinct constituents for tuning the surface oleophobicity.

Rapid Covalent Modification of Silicon Oxide Surfaces through Microwave-Assisted Reactions with Alcohols.

We demonstrate the method of a rapid covalent modification of silicon oxide surfaces with alcohol-containing compounds with assistance by microwave reactions. Alcohol-containing compounds are prevalent reagents in the laboratory, which are also relatively easy to handle because of their stability against exposure to atmospheric moisture. The condensation of these alcohols with the surfaces of silicon oxides is often hindered by slow reaction kinetics.

Improved Adhesion and Compliancy of Hierarchical Fibrillar Adhesives.

The gecko relies on van der Waals forces to cling onto surfaces with a variety of topography and composition. The hierarchical fibrillar structures on their climbing feet, ranging from mesoscale to nanoscale, are hypothesized to be key elements for the animal to conquer both smooth and rough surfaces. An epoxy-based artificial hierarchical fibrillar adhesive was prepared to study the influence of the hierarchical structures on the properties of a dry adhesive.

Self-assembly of nanoparticles onto the surfaces of polystyrene spheres with a tunable composition and loading.

Functional colloidal materials were prepared by design through the self-assembly of nanoparticles (NPs) on the surfaces of polystyrene (PS) spheres with control over NP surface coverage, NP-to-NP spacing, and NP composition. The ability to control and fine tune the coating was extended to the first demonstration of the co-assembly of NPs of dissimilar composition onto the same PS sphere, forming a multi-component coating. A broad range of NP decorated PS (PS@NPs) spheres were prepared with uniform coatings attributed to electrostatic and hydrogen bonding interactions between stabilizing groups on the NPs and the functionalized surfaces of the PS spheres.

Harnessing tunable scanning probe techniques to measure shear enhanced adhesion of gecko-inspired fibrillar arrays.

The hierarchical arrays of mesoscale to nanoscale fibrillar structures on a gecko's foot enable the animal to climb surfaces of varying roughness. Adhesion force between the fibrillar structures and various surfaces is maximized after the gecko drags its foot in one direction, which has also been demonstrated to improve the adhesion forces of artificial fibrillar arrays. Essential conditions that influence the magnitude of these interactions include the lateral distance traveled and velocity between the contacting surfaces, as well as the velocity at which the two surfaces are subsequently separated.