Dry Synthesis of Pure and Ultrathin Nanoporous Metallic Films.

Nanoporous metals possess unique properties attributed to their high surface area and interconnected nanoscale ligaments. They are mostly fabricated by wet synthetic methods that are not universal to various metals and not free from impurities due to solution-based etching processes. Here, we demonstrate that the plasma treatment of metal nanoparticles formed by physical vapor deposition is a general route to form such films with many metals including the non-noble ones.

X-ray Diffraction and Spectro-Microscopic Study of ALD Protected Copper Films.

In many applications of copper in industry and research, copper migration and degradation of metallic copper to its oxides is a common problem. There are numerous ways to overcome this degradation with varying success. Atomic layer deposition (ALD) based encapsulation and passivation of the metallic copper recently emerged as a serious route to success owing to the conformality and density of the ALD films.

Correcting the linear and nonlinear distortions for atomically resolved STEM spectrum and diffraction imaging.

Specimen and stage drift as well as scan distortions can lead to a mismatch between true and desired electron probe positions in scanning transmission electron microscopy (STEM) which can result in both linear and nonlinear distortions in the subsequent experimental images. This problem is intensified in STEM spectrum and diffraction imaging techniques owing to the extended dwell times (pixel exposure time) as compared to conventional STEM imaging. As a consequence, these image distortions become more severe in STEM spectrum/diffraction imaging.

Towards atomically resolved EELS elemental and fine structure mapping via multi-frame and energy-offset correction spectroscopy.

Electron energy-loss spectroscopy and energy-dispersive X-ray spectroscopy are two of the most common means for chemical analysis in the scanning transmission electron microscope. The marked progress of the instrumentation hardware has made chemical analysis at atomic resolution readily possible nowadays. However, the acquisition and interpretation of atomically resolved spectra can still be problematic due to image distortions and poor signal-to-noise ratio of the spectra, especially for investigation of energy-loss near-edge fine structures.

Reversed Janus Micro/Nanomotors with Internal Chemical Engine.

Self-motile Janus colloids are important for enabling a wide variety of microtechnology applications as well as for improving our understanding of the mechanisms of motion of artificial micro- and nanoswimmers. We present here micro/nanomotors which possess a reversed Janus structure of an internal catalytic "chemical engine". The catalytic material (here platinum (Pt)) is embedded within the interior of the mesoporous silica (mSiO2)-based hollow particles and triggers the decomposition of H2O2 when suspended in an aqueous peroxide (H2O2) solution.

A Lamellar Hybrid Assembled from Metal Disulfide Nanowall Arrays Anchored on a Carbon Layer: In Situ Hybridization and Improved Sodium Storage.

A lamellar hybrid assembled from metal disulfide (MoS2 , WS2 ) nanowall arrays anchored on nitrogen-doped carbon layers is developed via an in situ hybridization strategy through a synergistic pyrolysis reaction of thiourea and oxometalates. Such a hybrid provides adequate electrical and chemical coupling between the active materials and the carbon substrate, thus realizing a high-efficiency electron-conduction/ion-transportation system and exhibiting excellent sodium-storage properties.

Motion Control of Urea-Powered Biocompatible Hollow Microcapsules.

The quest for biocompatible microswimmers powered by compatible fuel and with full motion control over their self-propulsion is a long-standing challenge in the field of active matter and microrobotics. Here, we present an active hybrid microcapsule motor based on Janus hollow mesoporous silica microparticles powered by the biocatalytic decomposition of urea at physiological concentrations. The directional self-propelled motion lasts longer than 10 min with an average velocity of up to 5 body lengths per second.

Enzyme-Powered Hollow Mesoporous Janus Nanomotors.

The development of synthetic nanomotors for technological applications in particular for life science and nanomedicine is a key focus of current basic research. However, it has been challenging to make active nanosystems based on biocompatible materials consuming nontoxic fuels for providing self-propulsion. Here, we fabricate self-propelled Janus nanomotors based on hollow mesoporous silica nanoparticles (HMSNPs), which are powered by biocatalytic reactions of three different enzymes: catalase, urease, and glucose oxidase (GOx).

Catalytic mesoporous Janus nanomotors for active cargo delivery.

We report on the synergy between catalytic propulsion and mesoporous silica nanoparticles (MSNPs) for the design of Janus nanomotors as active cargo delivery systems with sizes <100 nm (40, 65, and 90 nm). The Janus asymmetry of the nanomotors is given by electron beam (e-beam) deposition of a very thin platinum (2 nm) layer on MSNPs. The chemically powered Janus nanomotors present active diffusion at low H2O2 fuel concentration (i.

High-performance ZnO nanowire transistors with aluminum top-gate electrodes and naturally formed hybrid self-assembled monolayer/AlO(x) gate dielectric.

A method for the formation of a low-temperature hybrid gate dielectric for high-performance, top-gate ZnO nanowire transistors is reported. The hybrid gate dielectric consists of a self-assembled monolayer (SAM) and an aluminum oxide layer. The thin aluminum oxide layer forms naturally and spontaneously when the aluminum gate electrode is deposited by thermal evaporation onto the SAM-covered ZnO nanowire, and its formation is facilitated by the poor surface wetting of the aluminum on the hydrophobic SAM.

Self-propelling nanomotors in the presence of strong Brownian forces.

Motility in living systems is due to an array of complex molecular nanomotors that are essential for the function and survival of cells. These protein nanomotors operate not only despite of but also because of stochastic forces. Artificial means of realizing motility rely on local concentration or temperature gradients that are established across a particle, resulting in slip velocities at the particle surface and thus motion of the particle relative to the fluid.

Microstructure, chemistry, and electronic structure of natural hybrid composites in abalone shell.

The crystal structure and chemical composition at the inorganic/inorganic and inorganic/organic interfaces in abalone shell (genus Haliotis) were investigated using advanced analytical transmission electron microscopy (TEM) methods. Electron energy-loss near-edge structures (ELNES) of Ca-M2,3, C-K, Ca-L2,3, O-K and low-loss EEL spectra acquired from aragonite and calcite are distinctly different. When comparing biogenic with inorganic material for aragonite, only minor differences in C-K fine structures could be detected.

Electroless synthesis of 3 nm wide alloy nanowires inside Tobacco mosaic virus.

We show that 3 nm wide cobalt-iron alloy nanowires can be synthesized by simple wet chemical electroless deposition inside tubular Tobacco mosaic virus particles. The method is based on adsorption of Pd(II) ions, formation of a Pd catalyst, and autocatalytic deposition of the alloy from dissolved metal salts, reduced by a borane compound. Extensive energy-filtering TEM investigations at the nanoscale revealed that the synthesized wires are alloys of Co, Fe, and Ni.