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Документ Evaluation of energy band structure of half-heusler alloy LiZnX (X = As, P and Sb) using first principle calculation(Національний технічний університет "Харківський політехнічний інститут", 2023) Ettah, Emmanuel; Ishaje, Michael E.; Minakova, Kseniia; Asuquo, Esther Offiong; Odey, Stephen U.The evaluation of energy band structure plays a vital role in understanding the electronic properties of materials. This research, we investigate the energy band structure of Half-Heusler alloys LiZn(X = As, P and Sb) using a first principle approach based on Density Functional Theory (DFT). These alloys are of particular interest due to their potential applications in thermoelectric and spintronics devices. The corresponding Density of States (DOS) for the tripartite compounds LiZnX (X=As, P and Sb) have been calculated and the contributions of the Li, Zn, As, P and Sb orbital to the Density of States at ambient pressure. This also confirmed that LiZnX (X=As, P and Sb) is a semi-conductor with a narrow band-gap between the occupied and unoccupied regions around the Fermi level. The orbitals Li-1s, As-4p, As-4s, Zn-3d has the highest contributions. The dominant of the orbitals P-1s and P-2p before the Fermi- level and Zn-2p after the Fermi-level are observed. We observed the dominant of the orbitals Sb-1s, Sb-3d, Li-1s, Li-2s, Zn-3d shows weak hybridization and low contribution. This features indicates that the covalent bond between these two atoms is weak, and could be responsible for the mechanical instability observed in the calculation. Meanwhile the band structure calculated and presented has narrow band-gab of 0.625. 0.937 and 0.313 respectively for the tripartite compound LiZnX(X=As, P, and Sb) and its a direct bandgap semiconductor. The obtained energy band structures provide valuable information about the electronic properties of LiZn (X = As, P and Sb) alloys. The presence of band gaps is crucial for thermoelectric applications, as it indicates the presence of regions where electrons and holes are confined, enabling efficient charge transport.Документ Optimization of flexible thin-film photovoltaic converters based on CdS/CdTe heterosystem for integration with solar thermal collectors(Національний технічний університет "Харківський політехнічний інститут", 2023) Shkoda, Dmytro; Zaitsev, Roman; Kirichenko, Mykhailo; Minakova, Kseniia; Leliuk, Stanislav; Khrypunov, MykhailoThe paper introduces the concept of a photoenergy system based on film photovoltaic converters using the CdS/CdTe heterosystem. The goal is to develop a design solution for a flexible thin-film photovoltaic converter system that can be directly mounted on a heat collector plate, integrating photovoltaic converters with thermal collector systems. The paper highlights the limitations of traditional silicon-based photovoltaic converters and propose using flexible photovoltaic converters based on CdS/CdTe, which have concentrated absorption within the visible range and allow unobstructed flow of long-wave solar radiation for efficient thermal energy generation. The paper discusses the methods of obtaining samples of flexible photovoltaic converter ITO/CdS/CdTe/Cu/Au solar cells, including the deposition of layers on polyimide films, chloride treatment, and annealing processes. Analysed the impact of the “chloride” treatment on the structural and optical characteristics of the base layers and present the overall appearance of the thin-film photovoltaic converter samples. The structural analysis of the cadmium telluride films is conducted using X-ray diffractometry techniques, while the optical properties are investigated using a spectrophotometer. The light-voltage characteristics of the photovoltaic converter samples are measured under illumination conditions, and various output parameters and characteristics of the photovoltaic converter are determined. The authors emphasize the significance of optimizing the performance of the cadmium telluride layer in the flexible photovoltaic converter structure and discuss the variation of technological parameters to enhance efficiency. Paper presents the output parameters and light diode characteristics corresponding to different thickness ranges of the CdS layer. Overall, this paper provides valuable insights into the development of flexible film photovoltaic converters based on the CdS/CdTe heterosystem for integrated photovoltaic and thermal collector systems. The experimental methods and results contribute to the understanding of optimizing the performance of the photovoltaic converters and offer potential applications for autonomous heat supply systems.Документ Technology Bases of Combined Photovoltaic Systems(2023) Zaitsev, Roman; Kirichenko, Mykhailo; Minakova, Kseniia; Khrypunov, Gennadiy; Nikitin, ViktorThis work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made.