I. I. Zverkova

Morphology of SiC nanowires grown on the surface of carbon fibers

SiC nanowires (NWs) with diameters of 20–200 nm and lengths from tens to hundreds of micrometers have been synthesized by the carbothermal reduction of colloidal silica. The morphology and microstructure of NWs have been studied in detail by electron microscopy techniques. SiC NWs have been found to be hexagonal prisms, “bamboo-like” nanorods and nanobelts. The NWs with a [111] growth axis are hexagonal prism nanorods, while the nanobelts have growth directions varying from [110] to [113]. It has been found that NW growth proceeds in two stages. Initially, SiC crystallites grow on the carbon fiber surface. These crystallites serve as seeds, on which the SiC NWs nucleate and grow. The crystallites containing microtwins and stacking faults (SFs) with a preferential [111] growth direction give rise to the growth of nanorods, while the nanobelts start growing on the (111) facets of relatively perfect crystallites. Wires with core (SiC)–shell (SiO2) structure have been obtained under special temperature treatment in air. The core–shell structure has been confirmed by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX) mapping techniques.

Synthesis and optical properties of monodisperse spherical Y2O3-Eu+3 particles

Research has been done into the luminescent properties of spherical Y2O3-Eu+3 nanoparticles with average diameters from 70 nm to 400 nm and 15% size dispersion, which are obtained by bath synthesis. The spectral-time characteristics of the most intense red luminescence of europium (~611 nm) have been found to be dependent on nanosphere diameter, dopant concentration and optical pump power density. It is shown that the effects are related to the influence of surface nonradiative recombination and modification of the spontaneous emission rate in nanometer-scale dielectric solids.

C-IOP/NiO/Ni7S6 composite with the inverse opal lattice as an electrode for supercapacitors

In this work, we demonstrate the results of studies on the synthesis, the structure and properties of carbon inverted opal (C-IOP) nanostructures, the surface of which is modified by oxide and sulfide of nickel. It is shown that the modification of the matrix C-IOP by nickel compounds led to a decreasing the specific surface area more than three times and was 250 m2/g. The specific capacitance of the capacitor with the C-IOP/NiO/Ni7S6 composite as electrode has increased more than 4 times, from 130 F/g to 600 F/g, as compared with the sample C-IOP without the modification by nickel compounds. The significant contribution of the faradaic reactions in specific capacitance of the capacitor electrodes of the composites is marked.

Synthesis, Structure, and Electrochemical Characteristics of Carbon Inverse Opals

Carbon structures with inverse opal lattice modified with nickel compounds are synthesized. The thermal treatment effect on phase composition of compounds is studied. The electrochemical characteristics of carbon structures as electrode materials in supercapacitors are measured for samples obtained from various organic precursors. A considerable contribution of Faraday reactions to the specific capacitance of a capacitor with composite-based electrodes is mentioned.

A novel way of synthesising C8 cubic carbon nanocrystals

We synthesized C8 nanocrystals (NCs) by carbonization and deposition of anthracene vapors onto various substrates. C8 nanocrystals have a bcc lattice with cell parameter a = (4.08 ± 0.02) A. A hypothesis is proposed on the possibility of C8 NC formation in the vapor phase and was confirmed in the experiment.

Synthesis and Modification of Carbon Inverse Opal Nanostructres Based on Anthracene and Their Electrochemical Characteristics

Carbon structures with the inverse opal lattice modified with nickel compounds have been synthesized by the template method. The carbon precursor is anthracene, whose molecule has a planar structure consisting of three benzene rings. The resulting nanostructures are characterized by X-ray diffraction, scanning and high-resolution transmission electron spectroscopy, and gas adsorption–desorption. Electrochemical characteristics of composites being used as the electrode material are measured.

Luminescence of Eu3+ rare-earth ions in Lu2O3 nanospheres

The kinetics of luminescence of Eu3+ ions in Lu2O3:Eu nanospheres with diameters of 100–270 nm and a small standard deviation of the size distribution <15% has been studied. A sharp decrease in the decay time of luminescence of Eu3+ ions in the red range with an increase in the diameter of nanospheres has been attributed to the appearance of a photon mode accelerating spontaneous luminescence, which is confirmed by the calculation of ranges of existence of whispering-gallery modes in studied nanospheres.

Opal-ZnO nanocomposites: structure and emission properties

The structure of the opal-ZnO composites has been studied by TEM and X-ray methods. It was found that the solid state reaction of the opal-ZnO interface interaction is occurring during the heat treatment of the infiltrated samples resulting in the formation of the zinc silicate β-Zn2SiO4 and its high temperature modification of willemite Zn2SiO4. Nanocomposite structure and emission properties have been studied in dependence on the filling degree. The blue luminescence at 430 nm stipulated for the β-Zn2SiO4 phase has been observed for the sample with 25 filling cycles. Angular dependences of the PL and Reflection spectra of the opal-ZnO composite with 4 filling cycles demonstrate the suppression effect of the ZnO spontaneous emission in the stop band.