3D Nano-objects Research Articles

Atomic-scale determination of surface facets in gold nanorods

It is widely accepted that the physical properties of nanostructures depend on the type of surface facets. For Au nanorods, the surface facets have a major influence on crucial effects such as reactivity and ligand adsorption and there has been controversy regarding facet indexing. Aberration-corrected electron microscopy is the ideal technique to study the atomic structure of nanomaterials. However, these images correspond to two-dimensional (2D) projections of 3D nano-objects, leading to an incomplete characterization. Recently, much progress was achieved in the field of atomic-resolution electron tomography, but it is still far from being a routinely used technique. Here we propose a methodology to measure the 3D atomic structure of free-standing nanoparticles, which we apply to characterize the surface facets of Au nanorods. This methodology is applicable to a broad range of nanocrystals, leading to unique insights concerning the connection between the structure and properties of nanostructures.

Application of micro- and nanoprobes to the analysis of small-sized 3D materials, nanosystems, and nanoobjects

The basic physics behind the interaction of ions with solid-state matter is discussed, with an emphasis on the formation of interaction products between the ions and target atoms. Processes covering modification of high-resistance materials for use in small-sized 3D structure technology are described. Current trends in and problems facing the development of the scanning nuclear microprobe (SNMP) are reviewed. The application of slow positrons to diagnosing materials is examined and the techniques of positron microscopy and microprobing are presented. The potential of near-field microwave microscopy for diagnosing superconducting ceramics and of microwave microscopy for nanotechnology applications are assessed. The examples given include the use of micro- and nanoprobes to analyze nanoobjects (such as green algae cells with 3D-distributed microelements, etc.), to develop the topological aspects of integrated microcircuits in nanoelectronics, and some other applications. The role of iron in pathogenesis of Parkinson's disease is highlighted, the latter being the subject of research in neurochemistry.

Применение микро- и нанозондов для анализа малоразмерных 3D материалов, наносистем и нанообъектов

Применение микро- и нанозондов для анализа малоразмерных 3D материалов, наносистем и нанообъектов

Organometallic Oligomer Resolved by Radial Distribution Function of X-ray Diffraction Analysis

Platinum-organic oligomers are actively studied for their large physical and functional properties such as solubility, processability, color, luminescence, and optoelectronics related to the different metal groups and auxiliary coligands around the metal coordination spheres. Previous studies on nanotechnology devices have shown that the structural organization of handled metallopolymer generates several 2D or 3D nano-objects, but only based on trans polymorph chains. Here we report the first self-assembly of powder cis-Pt-DEBP oligomers that shows great self-assembling ability to form nanoscale supramolecular architectures. As a powder is obtained that shows a poor crystalline organization of the aggregates, the energy-dispersive X-ray diffraction is the nondestructive technique of choice to obtain short-range order structural parameters of a single nano-object by radial distribution function analysis. The supramolecular architecture of 8-units-long chains reveals a self-assembling organization of 18 chains exhibiting an overall linear inverted open square structure. The ensemble of oligomer chains form a parallelepiped shape with small internal square cavities of approximately 3.2 nm diameter capable of hosting smaller molecules, which opens up to all applications where sieving and sensing is important. This structural investigation of short-range order materials has provided a substantial additional impetus to the field by opening up the area of self-assembled supramolecular materials based on metallopolymers for technological applications.

Electron-beam-induced welding of 3D nano-objects from beneath

Exposure of a sample to the electron beam in a scanning electron microscope (SEM)results in the growth of a film of amorphous carbon due to decomposition ofhydrocarbon molecules, which are always present in small quantities in the SEMchamber. This growth is induced mainly by secondary electrons backscattered byatoms of both the sample and substrate. We show that, because the secondaryelectrons are spread beyond the exposed area, this deposit can be grown in areas ofgeometric shadow and therefore can be used for bonding of different complex 3Dnano-objects to a substrate. This is demonstrated by welding 100 nm Fe–Co–Ninanoparticles to the surface of 2D graphite. The tip of an atomic force microscopewas used to probe the mechanical properties of the formed nanostructures. Weobserved that, for layers thicker than 25 nm, the nanoparticle is bonded so stronglythat it is easier to break the particle than to separate it from the substrate.