Проведено исследование структуры твердых растворов CdTe–Sb2Te3 и CdTe–CdSb (от 0 до 1019 ат. Sb см–3), полученных методом многостадийного твердофазного синтеза из элементов. Обнаружено, что при введении сурьмы Sb3+ в теллурид кадмия наблюдается уменьшение объема элементарной ячейки, а при введении Sb3- – увеличение. Показано, что параметры кристаллической решетки плавно меняются вплоть до концентрации сурьмы 1018 ат. см-3 в обеих системах, тогда как при увеличении концентрации сурьмы >1018 ат. Sb см-3 характерно резкое изменение объема элементарной ячейки, обусловленное существенным изменением структуры. Методом время-разрешенной микроволновой фотопроводимости изучена кинетика гибели носителей тока. Обнаружено, что при внесении в CdTe сурьмы пороговой концентрации (1018 ат. Sb см-3) наблюдается увеличение времен жизни фотогенерированных носителей тока, что можно связать с образованием ассоциатов дефектов и процессом самокомпенсации при легировании.

A set of AgxCu1 – xGaSe2 (0 ≤ x ≤ 1) solid solution powders has been prepared by solid-state synthesis. Using a combination of X-ray diffraction analysis and Raman spectroscopy, it has been found that the samples have a single-phase tetragonal structure (space group I-42d). It has been shown that their crystal lattice parameters do not follow Vegard’s law up to x ≈ 0.4. It has been revealed that the band gap of the samples also changes nonlinearly: initially it decreases and then increases. Studies of the low-temperature luminescence and microwave photoconductivity decay spectra have shown that a set of samples with x of 0 to 0.4 and further in the region with x > 0.4 is characterized by an increase in the photogenerated current carrier lifetime in AgxCu1 – xGaSe2 powders. The observed effect is apparently attributed to the replacement of deep charge carrier traps, such as selenium vacancies, by shallower cation vacancies.

Organic semiconductor small molecules (SMs) attract much attention to the design of various emerging photovoltaic and optoelectronic devices. High charge‐transport characteristics of SMs are important prerequisite for achieving outstanding performance of electronics. Herein, four promising SMs are investigated in terms of modulating charge‐transport properties by solvent engineering. It is shown that the hole mobility of thin films based on push–pull SMs can be effectively enhanced by the replacement of chlorobenzene with environmentally preferable hexane without changing a molecular structure of the compounds. As a result, 2–5 times higher hole mobility is achieved for hexane‐processed films that is attributed to the formation of favorable nanoscale morphology of films. This effortless approach can be applied to other organic semiconductor materials to precisely control the morphology and improve their electrophysical properties.

Conjugated donor-acceptor polymers have been regarded as attractive organic semiconductors for perovskite solar cells (PSCs) as hole-transport materials (HTMs). Herein, we report the design of four novel (X-DAD)n conjugated polymers based on alternating benzodithiophene unit (X) and thiophene-spaced benzene derivatives or pyridine (A). The variation of A building blocks has been shown to control the backbone geometry, which is crucial for achieving high charge-transport characteristics of HTMs. Particularly, introducing fluorine and methoxy-substituted blocks enabled rigid and planar backbone structure of PBPh-ff and PBPh-mm HTMs due to non-covalent intramolecular interactions. Benefiting from this merit, PBPh-ff and PBPh-mm exhibited improved hole mobilities and better hole extraction ability from MAPbI3. As a result, employing PBPh-ff as the HTM in n-i-p PSCs provided power conversion efficiency of 19.1% with an outstanding fill factor of ca. 80%. These findings highlight the importance of molecular design and geometry control of hole-transporting polymers for efficient perovskite photovoltaic devices. The control of backbone geometry is found to be important for reaching enhanced charge-transport characteristics of newly designed polymeric HTMs. Encouraging efficiency of 19.1% with good stability for p-i-n PSCs is achieved.

The structure of CdTe–Sb2Te3 and CdTe–CdSb solid solutions (0–1019 Sb atoms cm–3) prepared by multistage solid-state synthesis from the elements has been studied. It has been found that the introduction of antimony Sb3+ and Sb3− into cadmium telluride leads to a decrease and increase in the unit cell volume, respectively. It has been shown that the crystal lattice parameters gradually change up to an antimony concentration of 1018 atoms cm–3 in both systems, whereas an increase in the antimony concentration above 1018 Sb atoms cm–3 is characterized by an abrupt change in the unit cell volume due to a significant change in the structure. The decay kinetics of current carriers has been studied by the time-resolved microwave photoconductivity method. It has been found that the introduction of antimony into CdTe in a threshold concentration (1018 Sb atoms cm–3) leads to an increase in the lifetime of photogenerated current carriers; this fact can be attributed to the formation of defect associates and the occurrence of a self-compensation process during doping.

The study of marine lubricants using modern methods for quality control and diagnostics of engine conditions is an important task. The solution to this task determines the technical condition of ships, their performance, and accident-free operation in maritime transport. In this study, the properties of several marine motor oils were studied using broadband dielectric spectroscopy. The complex dielectric constant, conductivity, and loss tangent of base oil, Shell Rimula 15W40 oil fresh and used for 250 and 500 h were studied. The influence of the test voltage frequency and temperature on the selected electrical parameters was determined. In used oils, the DC conductivity decreases slightly, which is apparently due to the depletion of additives. The increase in the conductivity of all studied oils with increasing current frequency is caused by the displacement current. It is shown that dielectric losses increase with frequency as long as the polarization has time to follow the change in the field. A shift in the frequency at which the maximum loss occurs with a change in temperature was discovered. The activation energies of polarization and conductivity were determined. The thermal activation energies obtained from the conductivity and dielectric constant are not significantly different. For the first time, the distributions of the dielectric constant relaxation times for the studied lubricating oils have been obtained. The dielectric relaxation time distribution function depends on the composition of additives in the oil, wear particles, contaminants, and the chemical degradation of the oil during operation. For the first time, correlations have been established between conductivity and dielectric constant at different temperatures and frequencies. These correlations can be used to select frequency ranges that provide stable parameter values and maximum diagnostic ability.

The peculiarities of the electrochemical deposition of a copper layer on flexible titanium and tantalum supports as well as the modes of sequential electrochemical deposition of a tin layer on Cu/Ti and Cu/Ta supports and a nickel layer on the Sn/Cu/Ti and Sn/Cu/Ta supports are studied by cyclic voltammetry from the corresponding electrolyte solutions. The deposition potentials are found for each metal layer with regard to the support type. A wide series of stable precursor films Cu–Sn–Ni/Ti and Cu–Sn–Ni/Ta are obtained. The stage of annealing in the active sulfur atmosphere (sulfurization) is optimized aimed at the synthesis of stable compounds Cu2NiSnS4. Based on data obtained by the methods of XRD and Raman spectroscopy, it is shown that the synthesis of stable single-phase compounds Cu2NiSnS4 with the polycrystalline structure on the Ta and Ti supports requires that the annealing in the active sulfur atmosphere carried out at 550°С for 60 min.

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The polycrystalline samples of Cu2 – δSrSnS4 with a trigonal structure were prepared by solid-phase ampoule synthesis with a long annealing time (1944 h), and their crystal lattice parameters were refined and Raman spectra were obtained. For the first time, the effect of defect structure on the lifetimes of photogenerated current carriers in the polycrystalline powders was examined by combining time-resolved microwave photoconductivity and cathodoluminescence methods. A significant increase in the lifetimes during the conversion of Cu2SrSnS4 into Cu1.9SrSnS4 was found, which was probably due to changes in the defect structure.

Hybrid organic-inorganic perovskite solar cells (PSCs) have drawn great attention in the past decade due to the rapid growth of their power conversion efficiency (PCE) and the advantage of their low-cost fabrication. The hole-transport materials (HTMs) play a crucial role in achieving high efficiency and operational stability of PSCs. In this work, we report the synthesis of two novel conjugated polymers by coupling of the alkylsilyl-substituted benzo[1,2-b:4,5-b']dithiophene unit with the thiophene-bridged pyrazine block and their investigation as dopant-free HTMs in n-i-p PSCs. The devices with polymer PBPyT-ex (poly[(4,8-bis(5-(triisopropylsilyl)thiophen-2-yl)-2,6-benzo[1,2-b:4,5-b']dithiophene)-alt-5,5'-(2,5-bis(4-(2-ethylhexyl)thiophen-2-yl)pyrazine)]) demonstrate PCEs up to 17.5%, outperforming the 14.9% efficiency of PSCs with PBPyT-in (poly[(4,8-bis(5-(triisopropylsilyl)thiophen-2-yl)-2,6-benzo[1,2-b:4,5-b']dithiophene)-alt-5,5'-(2,5-bis(3-(2-ethylhexyl)thiophen-2-yl)pyrazine)]), which is attributed to the difference in the quality of HTM films. The results obtained feature the combination of pyrazine, thiophene and benzodithiophene units as a successful example of polymeric HTM backbone design for PSCs with encouraging efficiency and high operational stability over 1500 h under continuous illumination.

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The Cu2CrSnS4 microcrystalline powders and films with orthorhombic structure were obtained by solid-phase synthesis, and their Raman spectra were recorded for the first time. By optical spectroscopy, it was found that their Eg=1.70 eV, while in energy band gap of the powders there is a donor level with E=1.23 eV. It is shown for the first time that films of this material are photosensitive and have p-type of dark conductivity. Keywords: solid-phase synthesis, microcrystalline powder, film, dark conductivity.

Literature on new semiconductors, quaternary copper compounds Cu2AIIBIVS(Se)4 where A = Mg, Ca, Sr, Ba, Fe,Ni,Co, Cd, or Cr; and B = Sn, Pb, Si, Ge, Ti, Zr, or Hf, is reviewed. Compounds of this family can substitute for the more abundant Cu1 – δIn1 – xGaxSe2 (CIGS) chalcopyrites and Cu2 – δZnSnS4 – ySey (CZTSSe) kesterites used for thin-film solar cells. The review summarizes evidence from the world literature on optical and electrophysical properties of those compounds, the specifics of their manufacturing and solar cells based on them.

By solid-phase synthesis from elemental Cu, Ni, Sn, and S samples Cu 2-delta NiSnS 4 (0≤delta≤0.2) was prepared. The parameters of their crystal lattice have been refined. The lifetimes of photogenerated current carriers in Cu 2-delta NiSnS 4 were estimated for the first time by the contactless time-resolved microwave photoconductivity method. This times turned out to be tau~7 ns, which is comparable with the literature data for the times in kesterites CZTS. Herewith, in kinetics of loses of photogenerated cureent carriers is observed predominance of bimolecular recombination processes over capture processes. Keywords: Cu 2-delta NiSnS 4 , onequilibrium current carriers, lifetimes, kinetics.

The Cu2CrSnS4 microcrystalline powders and films with orthorhombic structure were obtained by solid-phase synthesis, and their Raman spectra were recorded for the first time. By optical spectroscopy, it was found that their Eg = 1.70 eV, while in energy band gap of the powders there is a donor level with E = 1.23 eV. It is shown for the first time that films of this material are photosensitive and have p-type of dark conductivity.