A high mobility of charge carriers and a low sheet resistance in graphene are the key indicators of its quality and applicability in electronic devices. In turn, the mobility of charge carriers in graphene is determined by graphene film smoothness. The electron scattering on structure defects of graphene film (wrinkles and grain boundaries) strongly affects the charge carrier mobility. In this work a simple and ultrafast approach for synthesis of graphene monolayer with the controllable smoothness and wrinkle density onto a resistively heated copper foil is presented. The method is a cold-wall chemical vapor deposition from methane. The fast synthesis of graphene with a full process cycle of 3 min is demonstrated. The structural defect density of polycrystalline graphene is optimized by appropriate combinations of methane concentration in the chamber and duration of synthesis process. Under the lower concentration of methane with the longer synthesis time the lower defect density in graphene appeared. The increase of process time from 30 s up to 10 min (under the decrease of methane concentration from 4.5 % to 0.36 %, respectively) leads to increase of average distance between wrinkles in graphene film from 6 µm to 35 µm. А charge carrier mobility as high as 2170 cm2V−1s−1 and a sheet resistance as low as 318 Ohm/□ under the lowest wrinkle density are measured for graphene polycrystalline monolayer deposited onto SiO2 substrate.

The rise in the antibiotic resistance of bacteria has increased scientific interest in the study of materials with unique mechanisms of antimicrobial action. This paper presents the results of studies on the antimicrobial activity of carbon materials and textiles decorated with them. A comparative analysis of the bactericidal and fungicidal activities of graphene oxide, electrochemically exfoliated multigraphene, carbon dots, and their combinations was performed. Microbiological studies on reference strains of E. coli, S. aureus, and C. albicans showed that graphene oxide inhibited growth with up to 98% efficiency. Electrochemically exfoliated multigraphene was less effective (up to 40%). This study found no significant antimicrobial activity of carbon dots and the combination of carbon dots with graphene oxide significantly weakened their effectiveness. However, the combination of electrochemically exfoliated multigraphene and carbon dots exhibits a synergistic effect (up to 76%). A study on the antimicrobial activity of decorated cotton textiles demonstrated the effectiveness of antimicrobial textiles with graphene oxide, electrochemically exfoliated multigraphene, and a combination of carbon dots with electrochemically exfoliated multigraphene.

In this article we provide the results of the synthesis of graphene films and discuss their potential applications in electronic structures. Graphene films were synthesized on copper foil using the CVD method at 1050 °C. During the initial stage of synthesis, graphene domains with hexagonal shapes and an average size of 10 μm were formed. The orientation and size of the graphene domains are based on the synthesis parameters and the copper foil. As the synthesis time increases, domain cross-linking occurs, resulting in polycrystalline continuous graphene film formation. Graphene films have areas up to 100 cm2 and thicknesses ~ 1 nm to 5 nm. To measure the Raman spectra, graphene films were transferred to SiO2/Si substrates. Graphene films exhibit an intense 2D peak that significantly exceeds the G peak of crystalline graphite. Flexible transparent conductive touch panels were created on the basis of the grown graphene films. A lamination method has been used to create graphene films that can be transferred from copper foil to polymer substrates. A laboratory touch screen with a graphene film acting as a capacitive touch sensor was constructed on the basis of the transferred film, and transparent electrodes for molybdenum disulfide-based photosensitive elements were also created. Resistive humidity sensors based on graphene films were developed and transferred to SiO2/Si and epoxy/Si substrates. The graphene humidity sensor has a low response, high temperature stability, and is highly reliable.

In this study, cotton e-textiles were obtained using two types of graphene oxide. The first type of graphene oxide was synthesized using the Hummers’ method. The second type was obtained by the electrochemical exfoliation of graphite in an ammonium salt solution. It was shown that e-textiles based on electrochemically exfoliated graphene have a higher electrical conductivity (2 kΩ/sq) than e-textiles based on graphene oxide obtained by the Hummers’ method (585 kΩ/sq). In addition, textiles based on electrochemically exfoliated graphene exhibit better washing and mechanical stress stability. The electrical resistance of the e-textiles increased only 1.86 times after 10 cycles of washing, compared with 48 times for the Hummers’ method graphene oxide textiles. The X-ray photoelectron spectra of the two types of graphene oxides showed similarity in their functional compositions after reduction. Studies of individual graphene flakes by atomic force microscopy showed that graphene oxide of the second type had a smaller lateral size. Raman spectroscopy showed a higher degree of sp2 structure regeneration after reduction for the second type of graphene. These properties and the tendency to form agglomerated particles determine the mechanochemical stability and high electrical conductivity of e-textiles based on electrochemically exfoliated graphene.

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и

Уважаемые коллеги!Благодарим Вас за проявленный интерес к Четвертой российской конференции «Графен: молекула и 2D кристалл» и желание принять участие в её работе.Конференция проходит в научно-образовательном центре города Новосибирска -Академгородке.Мероприятие посвящено актуальным направлениям исследований и разработок в области углеродных и низкоразмерных материалов.Проведение конференции поможет координации усилий ученых в решении современных проблем материаловедения и привлечению молодых исследователей для решения актуальных научных задач.Оргкомитет выражает особую благодарность НГУ, Центру компетенций НТИ «Моделирование и разработка новых функциональных материалов с заданными свойствами», компаниям «Диаэм», «НТ-МДТ Спектрум Инструментс» и корпорации "Графеновая Долина" за финансовую поддержку и журналам Аналитика, Наноиндустрия и РЭНСИТ за информационную поддержку.Искренне надеемся, что пребывание в Новосибирском Академгородке и в стенах Новосибирского государственного университета оставит множество положительных эмоций и

The goal is quantitative and qualitative assessment of the export potential, as well as designation of the main prospects for the development of grain economy in Kazakhstan. Methods – bibliometric, economic-statistical, comparative, system analysis, logical. Results – it is shown that global recession, rising gas and fuel prices have a negative impact on the increase in agricultural sector of the republic; bibliographic review of primary sources was carried out to determine organizational conditions for production and sale of grain to foreign markets, as well as the latest scientific achievements that contribute to the growth of grain exports; economic factors affecting export opportunities are analyzed; the level of self-sufficiency of grain products, the ratio of export and consumption of products of its processing are calculated; rating of indicators affecting food security and export activity was established, where the problems of depreciation of agricultural equipment and low domestic purchase prices for grains were highlighted; obstacles and shortcomings in organization of infrastructure of the industry for grain cultivation, taking into account disruption and rise in cost of logistics supplies, lack of access to the sea, underdevelopment of reclamation facilities and irrigation canals, lack of grain wagons and general price volatility, were considered; preferential conditions for the supply of Kazakhstani grain crops are substantiated. Conclusions – favorable prerequisites for the export potential of grain are summarized based on enhancement of state preventive measures, capital attraction, introduction of digitalization in agricultural sector, construction of new agro-industrial complexes, elevators and transport routes, creation of the necessary financial and material conditions for agricultural producers. To solve the problem of increasing the competitiveness of the country's grain subcomplex, it is necessary to provide quick transition of the industry to a new technological basis, which will be possible with effective public financial assistance.

In this study, the optical and structural properties of carbon dots (CDs) synthesized using a hydrothermal method were investigated. CDs were prepared from various precursors such as citric acid (CA), glucose, and birch bark soot. The SEM and AFM results show that the CDs are disc-shaped nanoparticles with dimensions of ~7 nm × 2 nm for CDs from CA, ~11 nm × 4 nm for CDs from glucose, and ~16 nm × 6 nm for CDs from soot. The TEM images of CDs from CA showed stripes with a distance of 0.34 nm between them. We assumed that the CDs synthesized from CA and glucose consisted of graphene nanoplates located perpendicular to the disc plane. The synthesized CDs contain oxygen (hydroxyl, carboxyl, carbonyl) and nitrogen (amino, nitro) functional groups. CDs have strong absorption in the ultraviolet region in the range of 200–300 nm. All CDs synthesized from different precursors displayed bright luminescence in the blue-green region of the spectrum (420–565 nm). We found that the luminescence of CDs depended on the synthesis time and type of precursors. The results show that the radiative transitions of electrons occur from two levels with energies ~3.0 eV and ~2.6 eV, which are due to the presence of functional groups.

Аннотация. В настоящее время актуальным является исследование возможностей использования углеродных точек для биомедицинских приложений. Создание на основе углеродных точек низкотоксичных наносистем, способных стать заменой токсичным полупроводниковымквантовым точкам и находящих применение в создании биосенсоров, биовизуализирующих и тераностических агентов, является перспективным и обладает новизной. В работе проведенсинтез углеродных точек гидротермальным методом с использованием в качестве углеродных прекурсоров глюкозы и сажи березовой коры. Легирование атомами азота углеродных точек было проведено в процессе синтеза путем добавления водного раствора аммиака. Определены средние размеры углеродных точек из глюкозы, которые равны 14 нм, из сажи березовой коры – 49 нм.Разница в размерах углеродных точек обусловлена разной природой углеродных прекурсоров. Полученные углеродные точки обладают поглощением в ультрафиолетовой области спектра и люминесценцией в сине-зеленой области. Был исследован состав функциональных групп на поверхности углеродных точек. Показано, что они представлены карбоксильными,карбонильными, гидроксильными и эпоксидными группами. Для изменения свойств полученных углеродных точек была проведена функционализация хромофорными группами. Установлено, что добавление хромофоров меняет спектры поглощения углеродных точек и сдвигает спектры люминесценции в красную область спектра.

We report an investigation of synthesis of multilayer MoS2 on transferred CVD graphene. To transfer the CVD graphene on target substrates four methods were used. Scanning electron microscopy and raman microscopy were used to investigate trans- ferred films. The synthesis of molybdenum disulphide films were carried out by the CVD method at 700°C for 15 minutes in Ar flow. Heterostructures MoS2/Graphene were obtained.

Carbon quantum dots were synthesized by the solvothermal method at 180 degrees C for 9 hours from citric acid and urea. The luminescence spectra recorded at excitation wavelengths of 300, 350, 400, 450 nm showed the presence of three luminescence peaks with the maximum at 440, 475, and 510 nm. When the suspensions of carbon dots are treated with a blue laser with a wavelength of 420 nm, the intensity of the peak at 440 nm remains unchanged, while the intensities of the luminescence peaks at 475 and 510 nm decrease. The luminescence with a peak at 440 nm is attributed to the emission of the core of the carbon dot, while the peaks at 475 and 510 nm are due to the emission of oxygen-containing functional groups located on the surface of the carbon dots.

Two-dimensional nanomaterials such as graphene can provide various functional properties to textiles, which have great potential in sportswear, healthcare etc. In this study, the properties of nylon and cotton-based electronic textiles coated with reduced graphene oxide are investigated. After reduction of graphene oxide coating in hydrazine vapor, e-textiles with a resistance of ~350 Ω/sq for nylon, and ~1 kΩ/sq for cotton were obtained. Cyclic mechanical bending tests of samples showed that the resistance increases during bending up to 10–20%. The use of bovine serum albumin as an adhesive layer improved the wash stability for samples with nylon up to 40 washing cycles. The use of BF-6 glue as a protective layer reduced changes in resistance during bending, and improved wash stability of cotton samples. It was shown that the resistance of the obtained samples is sensitive to changes in temperature and humidity. In addition, obtained e-textiles attached to a person’s wrist were able to measure heart rate. Thus, the obtained electronic textiles based on cotton and nylon coated with reduced graphene oxide demonstrates good characteristics for use as sensors for monitoring vital signs.

We study photoluminescence (PL) spectra and exciton dynamics of the MoS2 monolayer (ML) grown by the chemical vapor deposition technique. In addition to the usual direct A-exciton line, we observe a low-energy line of bound excitons dominating the PL spectra at low temperatures. This line shows unusually strong redshift with an increase in the temperature and submicrosecond time dynamics suggesting indirect nature of the corresponding transition. By monitoring the temporal dynamics of exciton PL distribution in the ML plane, we observe diffusive transport of A-excitons and measure the diffusion coefficient up to 40 cm2/s at elevated excitation powers. The bound exciton spatial distribution spreads over tens of micrometers in ∼1 μs. However, this spread is subdiffusive, characterized by a significant slowing down with time. The experimental findings are interpreted as a result of the interplay between the diffusion and Auger recombination of excitons.

In this work, samples of conductive textiles based on nylon and cotton with a surface layer of reduced graphene oxide were prepared and studied. The electrical resistance of the samples practically does not change with repeated cycles of bending and unbending, as well as after washing, which indicates the stability of the conductive coating.

Molybdenum- and tungsten-disulfide films are synthesized by chemical-vapor deposition. The set of optimal synthesis parameters (temperature, time, and amount and ratio of precursors) is established at which MoS2 domains with maximum lateral sizes of up to 250 μm on sapphire and MoS2 and WS2 domains up to 80 μm in size on SiO2 can be grown. Domain intergrowth leads to the formation of homogeneous single-layer MoS2 films. The Raman spectra of the synthesized films contain two characteristic peaks corresponding to the atomic vibrations in MoS2 and WS2. Photoluminescence of the single-layer and bilayer MoS2 films with a maximum intensity of 670 ± 2 nm and of the single-layer WS2 films with a maximum intensity of 630 ± 2 nm is detected. The photoluminescence spectral maps (the dependences of the photoluminescence intensity on the luminescence and excitation-light wavelengths) are measured. According to the measured data, the photoluminescence excitation spectrum of MoS2 has a maximum at 350 ± 5 nm and the photoluminescence excitation spectrum of WS2 has a maximum at 330 ± 5 nm. The I–V characteristics of the synthesized films are photosensitive in the visible spectral range.

Carbon dots (CDs) demonstrate unique luminescence properties due to conjugated π domains of the sp2/sp3 hybridized carbon core, quantum-size effects, and passivation of CD surfaces by functional groups. In this work we present hydrothermal synthesis of nitrogen-doped and boron-doped CDs, their morphological, structural, optical characteristics, and luminescent properties. The CDs are first synthesized from trans-aconitic acid. X-ray photoelectron and infrared spectroscopy data indicate that prepared CDs contain nitrogen and boron atoms. The photoluminescence quantum yield of N-doped and B-doped CDs is 26% and 9%, respectively.

Углеродные точки (УТ) демонстрируют уникальные люминесцентные свойства из-за со­пряженных π-доменов sp2/sp3-гибридизованного углеродного ядра, квантово-размерного эффекта и поверхностной пассивации УТ функциональными группами. В этой работе представлены легированные азотом и бором УТ, синтезированные гидротермальным методом: их морфологические, структурные и оптические характеристики, а также люминесцентные свойства. Впервые синтезированы УТ из транс-аконитовой кислоты. Результаты рентгеновской фотоэлектронной и инфракрасной спектроскопий показали, что полученные УТ содержат атомы азота и бора. Квантовый выход фотолюминесценции УТ, легированных азотом, равен 26 %, а легированных бором — 9 %.

Abstract Molybdenum- and tungsten-disulfide films are synthesized by chemical-vapor deposition. The set of optimal synthesis parameters (temperature, time, and amount and ratio of precursors) is established at which MoS_2 domains with maximum lateral sizes of up to 250 μm on sapphire and MoS_2 and WS_2 domains up to 80 μm in size on SiO_2 can be grown. Domain intergrowth leads to the formation of homogeneous single-layer MoS_2 films. The Raman spectra of the synthesized films contain two characteristic peaks corresponding to the atomic vibrations in MoS_2 and WS_2. Photoluminescence of the single-layer and bilayer MoS_2 films with a maximum intensity of 670 ± 2 nm and of the single-layer WS_2 films with a maximum intensity of 630 ± 2 nm is detected. The photoluminescence spectral maps (the dependences of the photoluminescence intensity on the luminescence and excitation-light wavelengths) are measured. According to the measured data, the photoluminescence excitation spectrum of MoS_2 has a maximum at 350 ± 5 nm and the photoluminescence excitation spectrum of WS_2 has a maximum at 330 ± 5 nm. The I – V characteristics of the synthesized films are photosensitive in the visible spectral range.