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Item Open Access Preparation of a Piezoelectric PVDF Sensor via Electrospinning(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Turdakyn, Nursultan; Medeubayev, Alisher; Abay, Ingkar; Adair, Desmond; Kalimuldina, GulnurDue to growth in robotics and automation in recent years, tactile sensors, which are designed to detect various information by physical contact, have gained much importance in the development of biomedicine, social assistance and industry. Piezoelectric tactile sensors fabricated from polyvinylidene difluoride (PVDF) are used for sensing vibrations because of their high sensitivity, mechanical flexibility, multi-technology compatibility, stability, and cheaper cost [1]. Generally, piezoelectric materials produce an electrical charge on the surface when stress is applied. Among the polymorphs of PVDF, only the β-phase exhibits piezoelectric properties. As electrospinning involves both mechanical stretching and poling, which facilitate the formation of β-phase, it is the most suitable method to increase the voltage output from a PVDF film [2-3]. In this study, we prepared an electrospun samples from 10-20 wt.% PVDF dissolved in different volume ratios of DMF/acetone and DMF/THF. The suitable solvent and wt.% of PVDF to obtain uniform and high β-phase content fibers were studied. The analysis of the introduced design of the sensor as two layers of the electrode in between of PVDF was performed using COMSOL Multiphysics software. The simulation study helps to optimize the development of sensors and allow their adjustments by comparing the analytical results of different changes of the output signal, eigenfrequency, vibration amplitude and applied pressure to the film.Item Open Access C-SiC and Si-SiC thin film systems as the anodes for LIBs(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Mukanova, Aliya; Mukhan, Orynbassar; Myronov, Maksym; Bakenov, ZhumabayThe miniaturization of the devices requires the miniaturization of energy storage systems. Lithium-ion batteries can provide the highest energy at smaller size and ligher weight among other energy systems. The present work reports the study of the development of new types of anodes – carbon film deposited on SiC thin film and Si thin film on SiC produced by chemical vapor deposition (CVD) method. The SiO2/MgF2/Al/Ti omics contacts were deposited by magnetron sputtering and annealed at 600 OC and served as the anode current collectors. The studies were accompanied by microscopic investigation and structural characterization.The the electrochemical results and characterization details will be detailed at the conference.Item Open Access The performance comparison of Li1.3Al0.3Ti1.7 (PO4)3 solid electroyte via various synthesizing methods(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Tolganbek, Nurbol; Mentbayeva, Almagul; Kanamura, Kiyoshi; Bakenov, ZhumabayDevelopment of all-solid-state Li-ion batteries (ASSLBs) has gained significant attention because of its electrochemical, chemical, mechanical, thermal stability and diminished flammability 1, 2. There are several types of solid electrolytes for ASSLBs such as LISICON-like, argyrodite, garnet, NASICON, Li-nitride, perovskite and Li-halide. Among all types, one of the most stable electrolytes with sufficient ionic conductivity is NASICON, particularly Li1.3Al0.3Ti1.7 (PO4)3 (LATP03)3. This research investigates different fabrication methods of LATP03 solid electrolyte such as solid-state, solution chemistry, sol-gel, spray-drying and a molten flux and their structural, morphological and electrochemical characterizations. Structure of LATP was confirmed by X-Ray Diffraction, and cell parameters were obtained using Rietveld refinement method via GSASII. The morphology of crystals were observed via scanning electron microscopy. The ionic conductivity of materials was determined by electrochemical impedance spectroscopy and it was carried out by applying electron conductive materials on a electrolyte’s both sides as blocking electrodes. It was found that the ionic conductivity of LATP03 depends on fabrication methods, grain size, theoretical density of pellets and morphology.Item Open Access Enhanced gas sensing properties of IZO thin films using SILAR(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Soltabayev, Baktiyar; Mentbayeva, Almagul; Çağırtekin, Ali Orkun; Acar, SelimIn the last decades, resistive gas sensors based on semiconductor oxides have been the topic of interest for a long time due to their high sensitivity to both oxidizing and reducing gases. These sensors meet the main market requirements such as low cost, small size, and easy maintenance. Currently, much attention has been attracted to finding an effective method to improve the nanomaterials’ sensing ability and selectivity. Sensor devices based on semiconductor oxide like ZnO are important sensing material for detection of hazardous gases [1]. ZnO is the most extensively applied as a gas sensing material, since it has remarkable characteristics necessary for an ideal metal oxide gas sensor such as wide band-gap energy (Eg=3.37 eV) and high binding energy (Ee=60 meV) [2]. Several approaches have been applied to improve gas sensing performance, for instance, morphological changes by doping metal. Especially, indium (In) significantly influences the electrical, chemical, structural, and gas sensing properties of ZnO. In the present work, the effect of In doping on the various properties of ZnO was investigated. The pure ZnO and indium doped ZnO thin films have been synthesized by the SILAR method. The obtained results clearly demonstrated a significant improvement in gas sensitivity by incorporating In into the ZnO.Item Open Access Investigating the Feasibility of Energy Harvesting using Material Work Functions(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Kenzhekhanov, Torybek; Abduvali, Durbek; Kalimuldina, Gulnur; Adair, DesmondThere is an on-going search for miniaturized efficient energy harvesting devices which will capture energy from the environment and transform and supply enough electrical power for the autonomous operation of small low power-demand electronic devices [1]. The concept of energy harvesting is especially attractive as it could be applied when battery replacement is difficult or when recharging in a conventional sense may prove to be not cost effective. Also this concept could be used successfully when continuous operation without maintenance is required. Electronic devices, with low power demand, can be energized using vibration energy harvesters which gather and transform energy from mechanical vibrations. This investigation looks at the feasibility of a method of energy harvesting from mechanical vibrations using the naturally occurring charging phenomenon within a system of two bodies which possess different work functions. A work function is defined as the minimum thermodynamic work (i.e. energy) needed to remove an electron from a solid to a point in the vacuum immediately outside the solid surface. A work function is not a characteristic of the bulk material but rather is a property of the surface of the material and depends on the material crystal face and presence of contaminants. The critical difference between a work function energy harvester (WFEH) and the electrostatic energy harvester is that the former does not require any electrets (dielectric materials that has a quasi-permanent electric charge or dipole polarisation) or external power sources. In this work, a brief review of similar technologies, namely piezoelectric, electromagnetic and electrostatic energy harvesters is first given. This is followed by the development of a theoretical model and an investigation of different WFEH operation modes and miniaturization of a WFEH, with conclusions on a possible optimum mode of operation and method of miniaturization. The design of an experiment to test the developed theory is then presented followed by some preliminary results. Generally it is found that WFEH has potential for use in energy harvesting applications with the possibility of giving equal or better output power when compared to traditional electrostatic harvesters.Item Open Access Light Management in Perovskite Solar Cell by Incorporation of Carbon Quantum Dots(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Maxim, Askar A.; Aidarkhanov, Damir; Atabaev, Timur Sh.; Jumabekov, Askhat N.; Ng, AnniePerovskite solar cells (PSCs) with a standard sandwich structure suffer from optical transmission losses due to the substrate and its active layers. Developing strategies for compensating for the losses in light harvesting is of significant importance to achieving a further enhancement in device efficiencies. In this work, the down-conversion effect of carbon quantum dots (CQDs) was employed to convert the UV fraction of the incident light into visible light. For this, thin films of poly(methyl methacrylate) with embedded carbon quantum dots (CQD@PMMA) were deposited on the illumination side of PSCs. Analysis of the device performances before and after application of CQD@PMMA photoactive functional film on PSCs revealed that the devices with the coating showed an improved photocurrent and fill factor, resulting in higher device efficiency. Meanwhile, other effective incorporation approaches of CQD in PSCs will be demonstrated. The underlying mechanism for the enhancement in device performance will be investiaged. The obtained results will provide an valuable insignt into the community for future light management during PSC fabrication.Item Open Access Surface morphology analysis of copper films produced by anodizing process(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Kadir, Meruyert; Alpysbayeva, Balaussa; Smirnov, VladimirCurrently, copper oxide films are of interest to researchers due to their environmental friendliness, rich resources and low cost. Copper oxide is a p-type semiconductor with a narrow band (1.9 eV-2.2 eV). This material is characterized by the possibility of effective application in sensors [1], hydrogen production [2], energy conversion [3], for the creation of supercapacitors [4], semiconductor catalysis [5], biosensorics [6]. The anodizing process allows you to obtain porous materials based on metal oxides. As with aluminum and titanium oxides, the anodizing process can produce a porous material based on copper oxide. Anodizing is a low-temperature, versatile, economical and simple method. In addition, anodizing allows to change the morphology and size of the copper oxide nanostructure to some extent [7]. In the course of practical work, a copper plate with a size of several microns was used as the initial material. The process of single-stage anodizing was performed at a temperature of 4°C for 90 seconds in an electrolyte of an acidic environment. As a result, the morphology of copper films was studied using Ntegra Therma (NT - MDT) atomic force microscopy. AFM shows that the surface morphology depends on various chemical bonds on the surface of copper.Item Open Access Synthesis and modification of Gadolinium ferrite nanoparticles for potential application in neutron capture therapy(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Zibert, Alexandr; Korolkov, IlyaFor decreasing the mortality from cancer diseases it is crucial to develop effective and low-invasive treatment methods. One of them is appeared to be neutron-capture therapy (NCT). It is based on a neutron capture reaction of isotopes delivered to tumor and thermal neutron flux. In this kind of reaction with 10B or 157Gd (or their combination) resulting particles have high index of linear energy transfer and low path length. That means effective ablation of cells in a short range. But still for NCT to become beneficial two technical problems should be solved: constructing of compact sources of pointed neutron flux and ability to directly deliver NCT agents in appropriate amount [1]. Delivering via magnetic nanocarriers (MNC) is considered to be promising. MNC are injected in-vivo and guided to tumor by external high-gradient magnetic field [2]. For this purpose, modified GdxFe3-xO4 particles were chosen to be MNC. GdxFe3-xO4 nanoparticles were synthesized with a chemical co-precipitation method. Average size of gained particles is 33±9 nm. For excluding the toxicity of Gd, particles were covered by tetraethoxysilane (TEOS). Size of TEOS-covered particle – 83 nm. Then it was functionalized with 3-(trimethoxysilyl) propyl methacrylate (MSPMA) to create double bond for further use in graft polymerization of glycidyl methacrylate that led to branched structure allowing attaching carborane cores with higher concentration. Final size is 95 nm. Gained NPs were characterized by SEM, EDX and FTIR spectroscopy. EDX spectroscopy confirmed the presence of covers. Figure 1 presents SEM scans.Item Open Access Etching the surface of aluminum foil using high-frequency plasma to produce a nanoporous aluminum oxide membrane(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Amirbekova, G.S.; Alpysbayeva, B.E.; Erlanuly, E.; Gabdullin, M. T.; Smirnov, V.Y.In recent years, the trend of creating and improving sensitive sensors has taken an important place in the field of medicine, environmental monitoring and research of biomolecular interactions. In addition, these nanoporous aluminum oxide films are actively studied in the fields of nanoelectronics, microbiology, and nuclear physics [1]. In this research work, a porous aluminum oxide membrane with pre-treatment of the aluminum coating with plasma was developed for the first time. The process of processing the aluminum film with plasma in a high-frequency discharge, in a vacuum environment, and as a result, the surface oxide layer was destroyed and a surface roughness was formed. During the experiment, a vacuum medium with a Vup-5 device was adopted, a plasma with a pink tinge of 0.6-0.7 Pa was formed between the two electrodes, argon gas was obtained as the main gas, and room temperature was used as the temperature parameter. In order to determine the differences that occur on the surface of the film, the power size was obtained to such a different extent. And the processing time for all films is the same value t=15 minutes. The process of electrochemical anodizing into an aluminum film with this surface treated with plasma was also carried out. As the electrolyte, orthophosphor was obtained, the chemical reaction took place at room temperature 190C, voltage U=80 V, t=30 min. The process of electrochemical anodizing was a step-by-step process. In the experiment in vacuum environment, in a high-frequency discharge plasma treated surface layer of the aluminum film, based on the electrochemical anodization received nanoporous aluminium oxide. In the course of the study, it was noted that the change in parameters, in particular, differs from the surface roughness due to the different power values of 20 W 50 W and 70 W (Fig. 1).Item Open Access Solar cell research at an altitude of 3340 meters above sea level(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Sadykov, T.Kh.; Zhukov, V.V.; Iskakov, B.A.; Nevmerzhitskiy, I.S.; Serikkanov, A.S.; Novolodskaya, О.А.; Tautayev, Y.М.Providing electricity to consumers in the mountainous regions is one of the urgent problems of power engineers. Laying and maintenance of power lines is expensive because of the difficult terrain and climatic conditions Providing a heating system for heating boilers, requires the acquisition and delivery of large quantities of combustible material. The heating season in the highlands lasts up to nine months. Considering all the costs of electricity consumption and heating, it becomes necessary to conduct research and evaluate the economic efficiency of using solar power plants, focused on providing electricity to consumers in mountain regions. In order to create a scientific basis for solving innovative problems in solar energy at the Tien Shan high-mountain cosmic ray scientific station (TSHSS), located at an altitude of 3340 meters above sea level, initiative work is underway to create a solar power station (SPS), assess its effectiveness, safety , environmental friendliness and reliability in work. At the moment, a solar power station has been created at an altitude of 3340 meters above sea level. A comparative analysis of the results of generating electricity from the same type of solar power plants located at altitudes of 800 and 3340 meters above sea level was carried out. It is shown that the amount of electricity generated by a solar power plant at an altitude of 3340 is 20 percent more than at an altitude of 800 meters.Item Open Access Fabrication of back-contact solar cells by microsphere lithography(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Umatova, Zarina; Jumabekov, AskhatThe back contact solar cells are a promising alternative to the traditional sandwich type devices. The most convenient and low cost method to fabricate back-contact solar cell devices is using microsphere lithography [1] as it can be performed without expensive photolithography tools and cleanroom. The self-assembly of polystyrene microbeads [2] was performed on top of APTES (3-Aminopropyl)triethoxysilane) functionalized surface of tin oxide layers on conductive glass substrates and deposited with magnetron sputtering. The deposition of microsphere beads on the substrates is achieved via electrostatic attraction forces between positively charged molecular monolayer-functionalized substrate and negatively charged micron-sized polystyrene microbeads with carboxyl surface groups. Resulting back-contact electrodes are used for fabrication of perovskite solar cell devices. Copper was chosen as a cathode layer in order to adapt existing processes on plastic substrates due to lower oxidation temperatures [3] compared to nickel [4].Item Open Access Sputtering of alkali metals into a gas medium upon excitation by products of nuclear reaction 6Li(n,α)3H(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Samarkhanov, Kuanysh; Khasenov, Mendykhan U.; Gordienko, Yuriy; Ponkratov, Yuriy; Bochkov, Vadim; Tulubayev, YevgeniyUranium fission fragments, as well as products of 3He(n,p)3H and 10B(n,α)7Li nuclear reactions were used in the nuclear reactor for gas ionization and excitation [1, 2]. The use of a nuclear reaction with lithium-6 with thermal neutrons was studied to a less extend, before our works [3, 4]. The large mean free path of tritium nuclei in lithium (130 μm) and gaseous media (35 cm in atmospheric pressure helium) makes it possible to excite large volumes of gases and provide a larger amount of power nested in the gas in comparison with reaction products with 10B. Several modification of irradiation devices with a lithium cell for reactor experiments were constructed. At studying luminescence of noble gases with excitation by nuclear reaction products: 6Li + n → 4He (2,05 MeV) + 3H (2,73 MeV), (1) it was found, that at a temperature of the lithium layer of~500 K, lines of lithium, as well as impurities of sodium and potassium in lithium appear in the spectrum [4, 5]. The vapor density significantly exceeding density of saturated lithium vapor during ordinary thermal heating of lithium is generated by the α-particles and tritium nuclei released from the lithium layer, as well as when the opposite wall is bombarded [5]. It was noted that the population of the lithium atom levels almost has no any effect on the population of 2p-levels of a noble gas atoms. The main channel leading to the population of lithium levels, apparently, is the Penning process (R is a noble gas atom): R(1s) + Li → R + Li+. Excitation of sputtered lithium atoms occurs as a result of further plasma-chemical reactions in a gas.Item Open Access Morphological Peculiarities from Lithium Plating and Stripping(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Billaud, Juliette; McNulty, David; Trabesinger, SigitaEnabling metallic-Li negative electrodes is motivated by a significant increase of energy density, both gravimetric and volumetric (Fig. 1), despite the excess of metallic Li accounted to ensure a stable potential. The projected gain in energy density for post-Li-ion batteries with metallic Li is twice than that possible to achieve with graphite, whereas with current and potential positive electrodes of Li-ion batteries it is about 30 % [1]. However, Li-metal as an anode is prone to dendritic growth and, therefore, is considered an unsafe option. It has been under investigation since early 1970s and the interest declined with the invention of Li-ion battery technology, which was considered safer alternative. However, recently interest in the metallic Li has been again on a sharp rise [2]. There is still insufficient fundamental understanding about the fundamental principles, governing electrochemical lithium plating/stripping, which often results in dendrite growth, electrolyte consumption, other undesired effects. [3] The present study aims to gain a comprehensive fundamental understanding of metallic-Li behaviour upon plating/stripping. As a first step, we performed post-mortem SEM analysis during the first two cycles in various electrolytes, in addition to studying the cycling performance in Li–Cu and symmetric Li–Li cells. Our post-mortem SEM study revealed that Li plates sporadically, where some of the regions are preferred for plating, despite ‘dead’ Li agglomeration on those particular spots, while the other regions are free of Li deposits (Fig. 2). The most interesting morphological changes are obtained during the initial stages of stripping and plating.Item Open Access Extremely stable zeolites developed via liquid-mediated self-defect-healing(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Iyoki, Kenta; Kikumasa, Kakeru; Onishi, Takako; Yonezawa, Yasuo; Chokkalingam, Anand; Okubo, Tatsuya; Wakihara, ToruThe successful application of zeolites in diverse fields largely relies on their high stability compared with other porous materials. However, the property requirements for zeolites have become stringent due to their diverse and demanding applications. Aluminosilicate zeolites are utilized for adsorptive and catalytic applications, wherein they are sometimes exposed to high-temperature steaming conditions (~1000 °C). Zeolites are exposed to severe steaming conditions in regenerators to remove coke, and over 400,000 t/y of catalysts are discarded due to degradation during the FCC process [1]. Recently, zeolites have been used in exhaust gas treatment processes, such as the selective catalytic reduction of NOx, catalytic oxidation for diesel engines, and hydrocarbon trapping [2], wherein they degrade due to interactions with high-temperature (>800 °C) steam. In automotive applications, degradation is often severe because zeolites are continuously exposed to steam without replacement. Therefore, the development of highly stable zeolites has become an important issue. As the degradation of high-silica zeolites originates from the defect sites in their frameworks, feasible defect-healing methods are highly demanded. Herein, we propose a method for healing defects to create extremely stable high-silica zeolites. High-silica (SiO2/Al2O3 > 240) zeolites with *BEA-, MFI-, and MOR-type topologies could be stabilized by significantly reducing the defect sites via a liquid-mediated treatment without using additional silylating agents. Upon exposure to extremely high-temperature (900–1150 °C) steam, the stabilized zeolites retain their crystallinity and micropore volume, whereas the parent commercial zeolites degrade completely (Figure 1). The proposed self-defect-healing method provides new insights into the migration of species through porous bodies and significantly advances the practical applicability of zeolites in severe environments.Item Open Access Methods of producing a polymer electrolyte on the surface of a 3D structure for lithium-ion batteries(2020-08) Nurymov, Zhainarbek; Yelemessova, Zarina; Beisembayeva, Kulzhan; Nurpeissova, Arailym; Kalimuldina, Gulnur; Bakenov, ZhumabayThree-dimensional microbatteries (3D-MBs) are energy storage devices intended for a large range of microelectronic applications. To date, a large number of various 3D electrodes have been developed (nanotubes, nanopillars and porous foams). However, electrolyte systems for these electrodes have not yet been implemented [1]. Solid polymer electrolytes (SPEs) have several advantages, such as leakage-free, low flammability, flexibility, electrochemical stability, high safety and excellent thermal stability [2], which allows their use in solid 3D batteries. SPEs facilitate the attainment of thin, flexible and adhesive coatings on microscopic surfaces. Gel or polymer electrolytes into 3D-MBs could be received by soaking a polymer matrix with conventional liquid electrolytes or by electrodeposition polymer layers directly on electrode surfaces [1]. In this research, we compared two methods for producing a polymer electrolyte polymethylmethacrylate (PMMA) on the surface of a 3D structure of Ni foam by drop coating [3] and electropolymerization [4] methods. Ni foam acts as a 3D electrode, because it has an uneven structure. The method of applying a droplet coating was carried out by dropping a solution of PMMA on a Ni foam in a glove box in an argon atmosphere. The electrochemical deposition of PMMA polymer electrolyte onto Ni foam has been accomplished using a cyclic voltammetry (CV) technique. At the potential 2.6V the formed polymer is anchored firmly to the cathode even in a good solvent for it. The studies of surface grafting polymers were carried out by microscopic investigation and structural characterization. The obtained PMMA film has a uniform fine structure.Item Open Access Enhancement of photovoltaic properties of polymer solar cells by modifying a structure of PEDOT: PSS layer(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Ilyassov, B.R.; Aimukhanov, А.К.; Rozhkova, X.S.; Zeinidenov, А.К.; Nuraje, N.Demand for developing robust renewable energy systems is increasing due to expiring fossil fuel deposits and ecological issues caused by using traditional energy sources. Among different renewable energy resources, solar energy is more attractive due to it can be transformed directly to heat, electricity or chemical energy. Photovoltaic devices are rapidly developing technology and have attracted attention of researchers and engineers from different fields. Polymer solar cells (PSCs) are very promising photovoltaic devices owing to facile fabrication method and cost-effectiveness of photoactive and semiconducting polymer materials [1]. PEDOT:PSS is semiconducting polymer materials with p-type conductivity which has become key components of PSCs [2]. The main role of PEDOT:PSS layer in PSCs is to extract photogenerated holes from photoactive layer and transport them to an external electrode [3]. The efficiency of hole extraction and transport depends on the quality of interface between PEDOT:PSS and photoactive layer and crystallinity of PEDOT:PSS. Here, we modified PEDOT:PSS layers obtaining by a spin-coating method from aqueous solution by adding 2-proponal. The improvement of structure and surface morphology was investigated by atomic force microscopy. Also, impedance spectroscopy technique was used to analyze charge transfer and transport. The modified PEDOT:PSS layers revealed better structure and surface morphology, and showed improved hole extraction and transport in comparison to an unmodified layer. PSCs with modified PEDOT:PSS layer have improved photovoltaic performance, which leads to enhancing the short circuit current density by 1.7 times, and power conversion efficiency and quantum efficiency of cells by 1.6 times.Item Open Access Abstract Book of The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08)The INESS 2020 topics covered the following and related areas: advanced nanomaterials for energy application, advanced energy storage, conversion and saving systems, materials for electrochemical sensor and electroanalytical applications, catalysis and fuel cells, battery monitoring and management systems, battery safety and utilization, development of electric vehicles and stationary energy storage. The scientists and students from Japan, Korea, France, Germany, China, Russia, Canada, UAE, UK, Turkey and Kazakhstan reviewed and discussed the recent progress and problems in materials science, nanotechnologies, ecology, renewable energy, energy storage systems and modeling methods in these fields.Item Open Access Dynamic Chemical Passivation of Absorber Layer Trap States and its Real-time Effect on the Device Performance in Back-Contact Perovskite Solar Cells(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Jumabekov, Askhat N.Hybrid organic-inorganic perovskites have been identified as one of the most promising classes of materials for photovoltaic and optoelectronic applications, due to their excellent electronic and optical properties, combined with their ease of fabrication. The efficiency of perovskite solar cells (PSCs) has increased at a remarkably fast pace, with the current maximum certified power conversion efficiency (PCE) reaching 25.2%. Conventional solid-state hybrid organic-inorganic perovskite-based solar cells have a sandwich type structure in which the perovskite absorber layer is positioned between bottom and top electrodes, typically a transparent conducting oxide (TCO) layer on glass, and an evaporated thin layer of gold or silver, respectively. Such an architecture for PCSs allows illumination of the cells only from the TCO side. Alternatively, the back-contact architecture offers the possibility of positioning both electrodes on one side of the absorber layer and shining light directly on the photoactive layer [1, 2]. This helps to avoid the occurrence of transmission losses caused by the charge collecting TCO electrode in the conventional sandwich structure for PSCs, and may have some potential application in constructing four or two terminal tandem solar cell devices. The back-contacted device architecture is also useful for conducting fundamental studies as it has an exposed photoactive area, permitting in situ measurements on the effects of chemical treatment, passivation and annealing. I will present a successful application of back-contact PSCs in studying the dynamic effect of a chemical passivation of the perovskite absorber layer and it is real-time influence on the device performance.Item Open Access Effect of copper sulfate concentration in growth solution on photocatalytic properties of ZnO/CuO nanostructures(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Kedruk, Y.Y.; Gritsenko, L.V.; Abdullin, Kh.A.; Cicero, G.Metal oxide semiconductors are the most suitable materials used for photocatalytic processes in industry and the environment (in particular, they are involved in wastewater decontamination processes). Semiconductors are relatively inexpensive, safe for health, chemically stable, and have high photosensitivity [1, 2]. One of the most challenging tasks at present is to improve the photocatalytic activity of photocatalysts for practical applications in the visible range, namely, high energy transfer efficiency, non-toxicity and low cost. The main efforts in the field of photocatalysis are devoted to the modification of existing photocatalysts to increase their photocatalytic characteristics [3]. In this work, semiconductor composites of copper (II) oxide and zinc oxide (ZnO/CuO) were synthesized using a low-cost method. To study the effect of the concentration of copper sulfate in the growth solution on the photocatalytic properties ZnO/CuO nanocomposites were synthesized by a low-temperature hydrothermal method. The aqueous solution contained copper sulfate, zinc chloride, and sodium hydroxide. A series of samples with different concentrations of copper sulfate (0.7 mmol - 2.0 mmol) was considered. The results of studying of the synthesized samples by electron microscopy showed that the obtained ZnO/CuO nanocomposites consist of thin filamentary ZnO rods with CuO nanoparticles attached to them. It was noted that an increase in the copper sulfate concentration in the growth solution to 2.0 mmol with the remaining parameters unchanged leads to an insignificant change in morphology: the volume of flocculent structures and the amount of CuO nanoparticles increase. Samples of the RhB solution for measuring of the optical density spectra were carried out every 30 minutes for 150 minutes. It should be noted, that with the used the same parameters for the ZnO/CuO powders synthesis, an increase in the amount of CuO nanoparticles in ZnO/CuO composites leads to a decrease in their photocatalytic activity which appears to be due to dimming effect at UV exposition.Item Open Access Effective penetration depth of optical radiation in nanoscaled modified Ge2Sb2Te5 films(The 8th International Conference on Nanomaterials and Advanced Energy Storage Systems; Nazarbayev University; National Laboratory Astana; Institute of Batteries, 2020-08) Zhakypov, Alibek; Maksimova, Suyumbika; Prikhodko, Oleg; Ismailova, Guzal; Turmanova, Kundyz; Tolepov, ZhandosThin films of Ge-Sb-Te (GST) chalcogenide semiconductor materials and, in particular, Ge2Sb2Te5 composition, are used for creation of optical information carrier on the basis of a “glass-crystal” reversed phase transition. To improve information recording parameters, GST compositions are modified with an admixture of metal. In this case, the impurity must be isovalent and isomorphic with one of the components of the matrix. For the Ge2Sb2Te5 composition, one of these impurities is silver. The report presents the results of study of the optical properties of nanoscale amorphous and crystalline Ge2Sb2Te5 films modified with Ag, and spectral dependence of the effective depth of penetration of optical radiation into these materials deff (λ) are also presented. Amorphous Ge2Sb2Te5 films modified with silver (a-Ge2Sb2Te5) were obtained by ion-plasma RF (13.56 MHz) magnetron sputtering of a combined target from a polycrystalline of Ge2Sb2Te5 and Ag. The film thickness l was ~ 100 nm, and the silver impurity concentration in the films was reached 5 at.%. Crystallization of the amorphous films was carried out by thermal heating. The phase state of the film structure was monitored using Raman spectroscopy. The optical properties of the films (transmission spectra T(λ) and reflection R(λ) of light) were recorded on a Shimadzu UV2000 spectrophotometer in the range from 300 to 1100 nm. The spectral characteristics of light absorption α(λ) of the films were calculated from the expression α(λ) = -1/l·{ln[T(λ)/(1-R(λ)2]}. The effective penetration depth deff (λ) of the optical radiation for the films was determined from the relation deff (λ) = 1/α(λ). Analysis of the spectral dependences deff (λ) for amorphous and crystalline Ge2Sb2Te5films showed that the effective depth of light penetration decreases significantly with increasing impurity concentration. In с-Ge2Sb2Te5crystalline films, it is much smaller than in amorphous a-Ge2Sb2Te5 films. The obtained results are important for creating optical information carriers based on nanoscaled Ge2Sb2Te5films using radiation from lasers with different wavelength.