Zinc oxide is one of the most promising materials used to create devices in the ultraviolet (UV) range. In this article, we study the sensor properties of ordered ZnO nanorod arrays grown by chemical vapor deposition. The possibility of their use as an indicator of UV radiation to control the dose of UV radiation, both from natural and artificial light sources, is assessed. The X-ray diffraction, Raman spectroscopy (RS), and cathodoluminescence (CL) data demonstrate the high quality of nanorods. Based on the ZnO nanorod array, a sensor prototype was fabricated based on the change in ZnO conductivity under the UV irradiation. A comparison of the response of such a sensor with the readings of a UV radiometer showed a high correlation.

The performance of a magnetic composite sorbent consisting of magnetic nanoparticles and carbon nanotubes (CNTs) in sorption of toxic metal ions [Be(II), Bi(III), Cd(II), Cr(III)] was studied in relation to the conditions of preparing the composite and its constituents. The pH dependence of the sorption of the metal ions was studied, and the sorption capacity of the composites containing CNTs of different morphology was determined. Be(II) and Cr(III) are taken up from aqueous solutions at pH 6, and Cd(II) and Bi(III), at pH 4.0–5.0. The composite containing CNTs prepared by catalytic pyrolysis of ethanol vapor on the Ni catalyst, CNT(Ni), exhibits the highest, and the sorbent containing CNTs synthesized on the Fe catalyst, CNT(Fe), the lowest sorption capacity. The sorption capacity of the composite containing CNTs prepared on the Co catalyst, CNT(Co), is intermediate. The dependence of the sorption ability of the composite on the ratio of its constituents was studied. The minimal content of magnetic nanoparticles ensuring the magnetism required for the efficient phase separation is 10% relative to the total sorbent weight. At this composition, the sorption capacity of the composite for Be(II), Bi(III), Cd(II), and Cr(III) is the highest: 8.0, 7.0, 6.2, and 6.7 mg g −1 , respectively. Despite lower sorption capacity of magnetic sorbents based on CNT(Fe) and CNT(Co), they can also be successfully used for removing toxic elements from aqueous media by static magnetic solid-phase extraction both in sample preparation for analysis and in treatment of various water reservoirs.

— The identification features of symmetric and nonsymmetric diaryl telluroxides via chromatography/mass spectrometry with electrospray ionization (HPLC/MS-ESI) are studied in the present work. Diaryl telluroxides exposed to ESI are shown to give rise to the formation of dimer ions and associate ions with the mobile phase components. Moreover, the influence of analyte concentration in the solution and the injection volume is found to impact the chromatography/mass spectrometry data.

AbstractThe influence of the length of ZnO nanorods (500 nm in diameter) on the mode structure and spontaneous luminescence in the ultraviolet spectral region is studied by optical luminescence microscopy. It is shown that individual nanorods with a metal mirror on one face exhibit only two or three laser modes in the case of short nanocavity lengths (8–30 μm). Different values of the optical losses of the longitudinal and transverse waveguide modes are established for a ZnO nanorod lying on a glassy substrate. The quadratic dependence of the spontaneous luminescence intensity on the rod length can be attributed to improvement of the optical quality factor Q of bound longitudinal modes of light within longer rods (the Purcell effect).

AbstractThe possibility of the nonresonance phase conjugation of light in an excited semiconductor medium is shown theoretically and experimentally. In epitaxial GaN films pumped with a nitrogen laser at room temperature, the induced phase conjugation of light in the visible and infrared spectral regions is detected for the first time. The dependences of the phase-conjugation signal intensity on the photon energy and laser-pumping intensity are studied. An interpretation of the effect as a result of the absorption and refraction of light at laser-induced free charge carriers in the semiconductor medium is proposed.

Magnetic sorbent MNP@CNT was synthesized on the basis of magnetic nanoparticles of magnetite (MNPs) and carbon nanotubes (CNTs). The sorbent was studied in extraction of toxic elements from aqueous media and its synthesis conditions were optimized. Isotherms of sorption of the metal ions under study from aqueous solutions were plotted in relation to their concentrations and solution pH values. The optimal conditions for extraction of Pb(II), Cr(III), and Bi(III) at pH 6 and Cd(II) at pH 4.5–5.0 were found. It was shown that the sorption capacity of the MNP@CNT sorbent for the elements under study is comparable with the capacity of carbon nanotubes, being 4.0, 3.8, 3.5, and 3.5 mg g–1 for Bi(III), Pb(II), Ct(III), and Cd(II), respectively. An important advantage of the magnetic composite sorbent over carbon nanotubes is the simple separation of the liquid and solid phases, compared with the conventional column variation of the solid-phase extraction. The resulting composite magnetic sorbent can be used both for analytical purposes, to preliminarily concentrate impurities, and for purification of various technological media and water basins in the environment to remove toxic elements.

The properties of nanorods made of high-energy-gap Zn x Mg1 – xO semiconductors are experimentally investigated using the new system of 3D manipulation of individual nanospecimens. The technology used to prepare Zn x Mg1 – xO nanorods via gas-phase deposition on a substrate, the process whereby individual nanorods are selected by means of nanocomposite tweezers with the shape-memory effect in the vacuum chamber of a two-beam scanning microscope, and the results obtained when their structure and morphology are experimentally studied using transmission electron spectroscopy are described. The prospects that nanophotonic, nanosensorial, and nanoelectronic devices can be fabricated from Zn x Mg1 – xO nanorods via the new nanomanipulation technique are discussed.

In this work, the results of formation of composite membranes with a thickness of about 200 μm with a high electric conduction based on porous silicon and graphene-like films have been presented. A method of CVD film synthesis that makes it possible to form a graphene-like coating on the inner surface of gradient-porous silicon with variable pore morphology across the thickness has been proposed. The pore sizes vary gradually from units of nanometers on the upper surface to several micrometers deep in silicon.

Electrospray ionization chromatography-mass spectrometry was used to study transarylation and disproportionation reactions of di(4-methoxyphenyl) and di(4-dimethylaminophenyl) telluroxides in refluxing toluene. The reaction mixture compositions were established based on the mass spectrometry data and relative retention times. General schemes for fragmentation of the reaction mixture components were suggested.

A novel technique has been demonstrated for direct chemical vapor deposition of carbon nanotubes (CNTs) on aluminum foil. It has been shown that the foil surface acquires catalytic properties after being held in an aqueous nickel nitrate solution for a certain time. CNTs were deposited by the catalytic pyrolysis of ethanol vapor. The hybrid materials thus prepared have the form of aluminum foil coated with “carbon wool” from CNTs on both sides. The layers have good adhesion to the aluminum substrate, which allows it to be deformed without causing the CNT layer to peel off. Such material is potentially attractive, in particular, for the fabrication of supercapacitors.

Textured polycrystalline aluminum nitride films are grown on a silica substrate by chemical vapor deposition using metallic aluminum and ammonium chloride as the initial reagents. The good texture and crystal quality of the prepared films are confirmed by raster electron microscopy, Raman spectroscopy, and X-ray diffraction.