Vol 45, No 9 (2019)

Polyaniline-based water-soluble ink has been developed to form hole-transport layers for perovskite solar cells by the ink-jet printing method. A study of the optical properties and surface morphology of layers composed of a complex of polyaniline and polysulfonic acid resulted in criteria determining the optimal conditions of their printing being suggested. The printed layers were found to be promising hole-transport layers for perovskite solar cells.

The results of experimental studies indicating the possibility of obtaining molybdenum carbide crystalline phases in a dc arc discharge plasma initiated inside a hollow graphite cathode in the air gaseous atmosphere under normal atmospheric conditions are presented. According to the X-ray diffraction data, two molybdenum carbide phases are identified in the powder synthesis product: Mo_1.2C_0.8 and Mo₂C, as well as graphite and metallic molybdenum. According to the transmission electron microscopy data, molybdenum carbide particles are in the carbon matrix and are characterized by dimensions mostly not exceeding 5–10 nm.

A family of normal mode spectra of hierarchically organized ensembles of identical interconnected oscillators with different topology of the organization is constructed. It is shown that treelike ensembles possess a devil’s-staircase-type fractal spectrum of normal modes; the number of degenerate modes increases with an increase in the number of tree branches and with introduction of additional connections between elements of the ensemble. The effect of ensemble topologies and bond strengths between elements of the ensemble on spectral characteristics is analyzed.

In this paper, we describe the main processes occurring during the generation of vacancies in aluminum in the presence of hydrogen by ab initio methods using the SCAN functional. Hydrogen is shown to reduce the generation energy of vacancies from 2.8 to 0.8 eV. In this case, the eight hydrogen atoms located in the tetrahedral lattice voids around single aluminum atom greatly facilitate its movement to the interstitial site. The dependence of the activation energy of hydrogen embrittlement of aluminum on the hydrogen concentration in aluminum and temperature is calculated based on the kinetic strength concept. Hydrogen is shown to reduce the time of aluminum destruction only if its mole fraction in aluminum is greater than the critical level (~ 3 × 10^–4 at T = 293 K).

Electrochemical capacitance–voltage profiling has been used to examine heterojunction solar cells based on single-crystal silicon. Specific features of the electrochemical capacitance–voltage profiling of modern multilayer heterojunction solar cells have been analyzed. The distribution profiles of majority carriers across the whole thickness of the samples were obtained, including, for the first time, those in layers of conducting indium tin oxide.

An analysis of the experiments on the kinetics of the rise and decay of the current under the influence of extreme ultraviolet radiation on the indium–zinc oxide filament layer obtained by the electrospinning method is given. It is shown that the rate of rise of photocurrent is controlled by the radiation intensity and its decay rate is controlled by the partial pressure of oxygen on the surface of the wires. Owing to a significantly larger area of the active surface, this UV sensor with a layer of nanoscale wires has a shorter response time in comparison with homogeneous film structures in which the oxygen adsorption sites are concentrated.

In classical X-ray lithography, the mask and resist layer are arranged perpendicular to the incident X-ray beam. Being absorbed in the resist layer, the X-ray beam induces a response in the form corresponding to its cross section. However, using a tilt and rotation of the mask/resist and sequential repeated exposures, it is possible to create three-dimensional forms that are accurate to within less than a micron. New approaches to the creation of 3D microstructures by deep X-ray lithography are described, which can ensure the formation of relatively large arrays.

Peculiarities of the dynamics of multicharged ion plasma in extended longitudinal low-inductance high-current discharge with a power supply system based on a high-voltage generator and transmission line have been analyzed. It is shown that, using power supply systems of this type, it is possible to manage stepwise compression and heating of plasma, which provides additional possibilities in programming the physical and spectroscopic characteristics of plasma, including its ion composition.

Theoretical models of reconstruction of the linear and angular parameters of motion using onboard integrated GLONASS systems with a two-position data receiver and three-component newtonometric unit for determining specific forces of nongravitational nature for a technological platform are described. An important element of the mathematical model design is represented by a specially developed stable procedure of multiply repeated numerical differentiation, which is independent of the discretization step under conditions of limited accuracy of computations and measurements. Results of a numerical experiment used to confirm the validity of the initial physical and mathematical notions underlying the proposed approach are presented.

The IR absorption spectra of subendothelial regions of the aortic valve cusps of a patient with calcified aortic stenosis diagnosis were measured by the attenuated total reflectance (ATR) spectroscopy technique in a frequency interval of 2500–3600 cm^–1 and analyzed in comparison to the spectra of healthy human tissues and reference spectra of a pig’s healthy bone and aortic valve. The IR absorption band structure in this spectral region was studied by means of expansion into Gaussian components. The energies of hydrogen bonds (H-bonds) involving O–H groups were estimated. It is established that, among all samples studied, the energy of H-bonds between hydroxyl groups reaches maximum in the bone tissue.

The kinetics of singlet oxygen phosphorescence in HeLa cells suspended in phosphate buffered saline (PBS) being generated under photosensitized excitation with Radachlorin photosensitizer has been observed and studied. The characteristic time of singlet oxygen generation and its lifetime in HeLa cells have been determined. The experimental data analysis demonstrated that the singlet oxygen lifetime in cells decreases as compared to that in Radachlorin solutions in PBS and in water, while the photosensitizer triplet state lifetime increases.

Deformation behavior of ZrO₂−Y₂O₃ ceramics under conditions of diametral compression has been studied by method of digital image correlation. Spatiotemporal patterns of strain localization along the axis of a deformed sample (ε_xx(x)) and across this axis (ε_yy(y)) were obtained. It is established that the ε_xx and ε_yy deformations accumulated during the diametral compression test are inhomogeneously distributed over the sample. This is manifested by variation of the microstructure characteristics such as the size of the coherently diffracting domains of a tetragonal phase and microstresses and leads to the tetragonal–monoclinic phase transformation. This pattern of strain localization is correlated with the observed inhomogeneity of microstresses arising in the material volume.

Gain characteristics of heavily doped Al_xGa_{1 –x}N/AlN:Si structures with c x = 0.65 and 0.74 have been studied under pulsed optical pumping by Nd:YAG laser radiation at wavelength λ = 266 nm. The absolute values of the optical gain measured at spectral maximum of the room-temperature luminescence spectrum reach (0.5–6) × 10³ сm^–1 at an pumping power density of 8–600 kW/cm². Cross sections of the radiative and donor–acceptor recombination are close to each other and exceed 10¹⁶ cm².