Nanotechnologies in Russia最新文献

At present, there is an increasing need to create energy-efficient power supplies for wearable devices. In recent studies, we found that nitrogen-doped carbon nanotubes (N-CNTs), which exhibit anomalous piezoelectric properties, can be used as the basis for such devices. This paper presents the results of studying the effect of the activation time of catalytic centers during the growth of carbon nanotubes on the value of their piezoelectric strain coefficient and the value of the generated current. It is found that with an increase in the activation time of catalytic centers from 1 to 30 min, the value of the piezoelectric strain coefficient decreases from 19.78 to 4.49 pm/V, which is associated with a change in the geometric dimensions of the catalytic centers and, consequently, the structure of the N-CNTs. The results obtained can be used to create energy-efficient piezoelectric nanogenerators.

Terbium-161 is a radioisotope characterized by β-emission, emission of Auger electrons, conversion electrons, and, to a lesser extent, gamma and X-rays. Tb-161 radioconjugate with the DOTA-PSMA-617 ligand (considered as a promising drug for radiotherapy of prostate cancer) was synthesized on the basis of components produced in Russian Federation. The physicochemical characteristics of ¹⁶¹Tb-DOTA-PSMA-617 were investigated. The ability of the radioconjugate to bind to cell membrane receptor was studied on cell line in vitro and in mice in vivo using a new CT26-PSMA cell model representing genetically modified mouse carcinoma cells expressing human PSMA. The pharmacokinetics and biodistribution of the radioconjugate were investigated. The radiopharmaceutical demonstrated highly specific accumulation in the tumor expressing human PSMA unlike in the control tumor. It was not significantly accumulated in the kidneys and other animals’ organs. The blood half-life time of the radiopharmaceutical was determined as 38.4 min. Thus, according to the main criteria, the synthesized radioconjugate ¹⁶¹Tb-DOTA-PSMA-617 is a promising radiopharmaceutical for the treatment of prostate cancer.

The features of the morphology and physical–chemical state of five epitaxially formed monolayers of tin at the interface with a thin silicon buffer layer on a silicon substrate and transformation of the epitaxial structure as a result of in situ thermal annealing from the point of view of the charge state of silicon atoms are studied. X-ray photoelectron spectroscopy using synchrotron radiation and scanning electron microscopy are used. The possibility of oxygen atom transport to the silicon buffer layer during storage of the structures in laboratory conditions is shown. Annealing in ultrahigh vacuum causes a restructuring of the surface of such structures, which is accompanied by oxygen atom redistribution to the exposed surface of the epitaxial silicon buffer with the formation of a thin SiO₂ layer and the assembly of tin into clusters on this surface.

In the present work, the peculiarities of electron transport upon the transition from quantum wires with smaller cross sections to quantum wires with larger cross sections are studied. The probabilities of electron transfer through corresponding contact regions of such quantum wires are calculated as functions of the charge-carrier kinetic energy and quantum-wire cross section ratio. The peculiarities of electron transfer through defect regions in quantum wires in the form of rectangular grooves and steps are also studied. The probabilities of electron transfer through the defect regions are calculated as functions of the electron kinetic energy and geometry and size of the defects. The probability density distributions of electron detection in different regions of the modeled structures are calculated.

Thin copper oxide films are produced by the sol-gel technique. The films have a fine-grained structure. After annealing at temperatures of 400 and 500°C, the grain size decreases. The films have high values of the gas sensitivity (resistance change of 30%) and low values of the temperature of the maximum gas sensitivity (180–190°C) to ethanol, acetone, and ammonia vapors in the air.

This review presents theoretical and experimental studies of hybrid and metal halide perovskites, which have found active application in photoelectronics and optoelectronics. The extremely low thermal conductivity of halide perovskites has attracted the attention of researchers for their investigation as thermoelectric materials as well. This review discusses methods of synthesis, the microstructure, and thermoelectric properties of thin-film and bulk halide perovskites studied over the past five years. Possible pathways to enhance the efficiency of these materials are also described.

A technology for the functionalization of hybrid nanostructures made of reduced graphene oxide and single-wall carbon nanotubes with BaO nanoparticles is developed. Quantum methods are used to numerically establish the regularities of reducing the work function of hybrid nanostructures. An increase in the emission current of the functionalized hybrid nanostructures by more than 40 times compared to conventional samples is established. Such hybrid nanostructures may be promising for devices with a current density of at least 2 A/cm².

The crystal structure of iron chloride in channels of single-walled carbon nanotubes (SWCNTs) is investigated. The channels of SWCNTs with mixed conductivity and a diameter of ~1.4 nm are filled with iron chloride by means of the melt method. On the basis of high-resolution transmission electron microscopy (HRTEM) images, the crystal structure of the encapsulated iron chloride is modeled, and TEM images are produced. It is shown that the encapsulated iron chloride has a one-dimensional structure that differs from the three-dimensional structure with the (Rbar {3}m) space group and the lattice parameters a = 3.5980 Å and c = 17.5360 Å. The filled SWCNTs are investigated via Raman spectroscopy. Modification of the electronic structure of the SWCNTs is revealed. The obtained data are important for applying filled SWCNTs in nanoelectronics, catalysis, sensors, biomedicine, electrochemical energy storage, spintronics, magnetic storage, and magnetic recording.

We have shown a novel method for the synthesis of iron silicide nanoparticles on a water-soluble NaCl substrate using thermal layer-by-layer deposition of Fe–Si and post-annealing in ultra-high vacuum. The crystal structure, morphology and optical properties of highly dispersed Fe–Si-containing thin films have been studied. As a result, Fe₃Si nanoparticles were found to spontaneously form on the surface of salt with an excess of iron in a wide stoichiometric range. We propose a simple method to control the geometric shape of synthesized Fe–Si ferromagnetic nanoparticles by preparation of NaCl surface.

Within the framework of this work, the influence of the type of precursor and precipitator on the structure of magnesium carbonate is studied. Nanoparticles are obtained by chemical precipitation in an aqueous medium. Magnesium acetate, magnesium nitrate, and magnesium chloride are used as the precursors of magnesium, and potassium carbonate, ammonium carbonate, and sodium carbonate are used as the precipitators. The obtained samples are examined by X-ray diffraction analysis, scanning electron microscopy, and infrared (IR) spectroscopy. It is established that magnesium acetate and ammonium carbonate are optimal precursors and precipitators for the production of magnesium carbonate nanoparticles, respectively, since the particles in this sample have a diameter from 40 to 100 nm. As a result of X-ray diffraction analysis, it is found that three phases of substances are present in the resulting sample: anhydrous magnesium carbonate, Mg₂(CO₃)(OH)₂·3H₂O, and magnesium oxide.