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Characterization of the perovskit photovoltaic cells
Dvořák, Tomáš ; Strachala, Dávid (referee) ; Novák, Vítězslav (advisor)
The thesis discusses the problematics of perovskite solar cells. The introduction deals with the history of the solar cells as the next part is dedicated to generations of them as well as to their principle and the variables measured in photovoltaic cells. The next part deals with perovskites, their properties and structure. Later the part about perovskite solar cells follows. The last part is dedicated to experiments which were executed on samples of perovskite solar cells.
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Photoimpedace spectroscopy characterization of the perovskit photovoltaic cells
Henek, Tomáš ; Vaněk, Jiří (referee) ; Novák, Vítězslav (advisor)
This work studies the subject of perovskite solar cells. The structure of perovskites is described along with a portion of photovoltaics history that led to the employment of perovskites as absorpsion layers. Further, methods of measurement for solar cells such as impedance spectroscopy, photospectroscopy and load characteristics are summarized. Lastly there is a description of already done analytics of perovskite solar cells with the summary of the results. In the practical part, there are measurements made to find out any effect of cell topology or light source wavelength on the cell performance.
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Study of the crystallization process kinetics of perovskites and their precursors
Sršeň, Bohdan ; Gavranović, Stevan (referee) ; Zmeškal, Oldřich (advisor)
This thesis focuses on the properties of perovskite materials and examines the methods for preparing layers and potentially monocrystals of these materials. Emphasis is placed on analyzing the electrical and optical properties of perovskites. The experimental part of the thesis is dedicated to the preparation of perovskite material layers and subsequent measurement of their electrical properties during the crystallization process and after its completion. The prepared samples exhibit a macroscopic size due to the interdigitated electrode structure, ensuring a large active surface area. Special attention is given to the influence of nano-particles on the crystallization process and the resulting current-voltage (I-V) characteristics of the prepared samples. Understanding how the presence of nano-particles affects the crystallization and electrical properties of perovskite layers is crucial. These insights are necessary for further optimization of the preparation processes and enhancing the performance of perovskite materials in their final applications. The thesis provides an overview of the properties of perovskites and their preparation. The experimental results yield important insights into the relationship between nano-particles, crystallization, and electrical characteristics of perovskite layers.
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Novel materials for organic and hybrid electronics and photonics
Kratochvíl, Matouš ; Yumusak,, Cigdem (referee) ; Táborský, Petr (referee) ; Weiter, Martin (advisor)
Obor organické elektroniky nabízí jedinečnou možnost masové výroby levné a ekologicky přívětivé elektroniky. Otevírá dveře novým funkcím a tvarům zařízení, které standardní elektronika na bázi kovu a křemíku neumožňuje Možnosti dané povahou organických látek a pokrok ve výzkumu syntézy nás zásobují novými materiály pro fotonické aplikace. Hlavní motivací této práce je hledání nových materiálů a zkoumání vztahu mezi jejich molekulární (a krystalickou) strukturou a vlastnostmi. Tato práce je zaměřena na studium optických a/nebo elektrických vlastností nových materiálů pro fotonické aplikace. Materiály prezentované v práci jsou organické i hybridní organicko-anorganické, u nichž je snaha získat to nejlepší z obou světů. Výzkum prezentovaný v této práci se skládá ze tří samostatných částí, které jsou propojeny cílem studovat vztah mezi strukturou materiálu a jeho vlastnostmi a metodami používanými ke studiu těchto vlastností. První část si klade za cíl představit materiály vykazující účinnou fluorescenci v pevné fázi (Solid-State Fluorescence, SSF). V této práci jsou prezentovány dvě série materiálů vykazujících SSF. Barva emise je řízena změnami skupin přitahujících elektrony v push-pull systémech molekul. Výsledky ukazují efektivní (>10%) emise pokrývající většinu viditelného spektra (~450–650 nm). Druhá část prezentovaného výzkumu zkoumá vliv thionace na známou skupinu nízkomolekulárních polovodičů – diketopyrrolopyrrolů (DPP). Prezentované výsledky ukazují ve studovaných molekulách výraznou preferenci n-typové chování následkem thionace, s řádovým zvýšením pohyblivosti elektronů, a také působivě nízko ležící hladiny LUMO (~ 4,5 eV). Třetí část uvedených výsledků je zaměřena na perovskitové materiály pro fotonické aplikace. Hybridní materiál – organo-olovnato-halogenidový perovskit je již téměř půldruhého desetiletí v centru pozornosti výzkumníků v oblasti pokročilé fotoniky. Perovskitové solární články prokazují pozoruhodnou účinnost, avšak jejich využití stále brání problémy se stabilitou. V této práci je prezentována studie stability jako referenční bod pro další výzkum v této oblasti a pro získání vhledu do procesů ovlivňujících stabilitu perovskitových materiálů a solárních článků. Následně je navržen a otestován přístup ke zvýšení stability a výkonu článků, využívající materiály studované ve druhé studii.
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Highly porous ceramic oxide materials for environmental catalysis
Husťák, Miroslav ; Částková, Klára (referee) ; Cihlář, Jaroslav (advisor)
As far as the replacement of fossil fuels with more environmentally friendly options is concerned, hydrogen is considered as the most promising source of energy. Currently, hydrogen is mainly produced through the method of methane reforming. This method requires the utilisation of catalysts made of precious metals. This master's degree thesis therefore investigates perovskite materials SmCoO3, Sm0,8Ca0,2CoO2,9, SmCo0,8Al0,2O3 and Sm0,8Ca0,2Co0,8Al0,2O2,9, which could be utilised as catalysts in the production of hydrogen by methane reforming. Methane reformation occurs on the surface of a catalyst. Therefore, it is desirable to ensure that the specific surface area of a catalyst material is as large as possible. For that reason, the aforementioned perovskite materials were prepared by two sol-gel methods, which are expected to create perovskites with large specific surface areas. It was investigated in the course of the work how the method of synthesis affects the structure and catalytic properties of individual materials. The SmCo0,8Al0,2O3 material prepared by a sol-gel synthesis with propylene oxide as a gelation agent demonstrated the best results - the measurement of catalytic activity showed that the methane conversion had achieved the value of 99%.
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Characterization of the perovskit photovoltaic cells
Kaliyev, Alexey ; Jandová, Kristýna (referee) ; Novák, Vítězslav (advisor)
The work is focused on problems of perovskite photovoltaic cells. The theoretical part describes the properties of perovskite structure, its composition and use in solar cells. There is also a brief information on silicon-based solar cells, which is followed by a comparison of the two systems. The measurement methods, which this stated and described here are used to understand problematics photovoltaic, determination of efficiency, stability and durability of the solar cell. In the practical part will focus on the application of these methods, discussion and evaluation of results.
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Characterization of perovskite solar cell materials by transient techniques
Nakládal, Martin ; Zmeškal, Oldřich (referee) ; Novák, Vítězslav (advisor)
This thesis deals with the study of the lifetime of charge carriers in perovskite single crystals. The principle of perovskite solar cells is formulated, their main structures are characterized and the history of the development of perovskite solar cells is summarized, especially in terms of efficiency. The properties of perovskite single crystals with perovskite solar cells are compared. For measurement purposes, transient methods, impedance spectroscopy, load characteristics and the dependence of sensitivity and photocurrent on the wavelength of incident radiation are described. The practical part deals with the method of measuring and evaluating the lifetime of charge carriers in the investigated perovskite single crystals.
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Impedance spectroscopy characterization of perovskite solar cell materials
Křečková, Jitka ; Vanýsek, Petr (referee) ; Novák, Vítězslav (advisor)
The Master‘s thesis deals with the topic of perovskite solar cells with the main focus on the materials used for the active layer. In the introductory part, the electrical and optical properties of halide perovskites are described and specific examples of perovskite crystals are introduced. The description of impedance and photoimpedance measurement methods used for characterization of perovskite solar cells is also included in the thesis. The measurement of electrochemical impedance spectroscopy was conducted on four perovskite crystals and equivalent circuit was formed to fit the obtained data. Parameters of the circuit elements were acquired using the fitting method and were further evaluated in experimental part of this thesis.
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Charakterizace vlastností perovskitovských fotovoltaických článků
Salaukou, Aleh ; Vanýsek, Petr (referee) ; Novák, Vítězslav (advisor)
This work deals with photovoltaic cells based on perovskite. The theoretical part describes the basic properties of perovskite structure, its composition and its using in solar cells. In addition, the work provides basic information about photovoltaic and silicon solar panels. Information on photovoltaic cell measurement methods such as impedance spectroscopy, photoimpedance spectroscopy, and load curve method are also presented here. Practical part of the Bachelor work deals with the application of measuring methods described in the theoretical part, the determination of equivalent circuits and discussions about the results obtained.
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Preparation and characterization of perovskite solar cells
Juřík, Karel ; Salyk, Ota (referee) ; Pospíšil, Jan (advisor)
This work deals with the perovskite photovoltaic cells. The first part summarises the basic information about this technology and shows the most important milestones in its development. Following part includes the parameters required to characterise the electric properties of a photovoltaic cell and the assessment of its quality. The experimental part of this thesis aims to describe the influence of the annealing time of the perovskite active layer on the final efficiency of created solar cells. The best results were determined to be achieved with the annealing time of 90 minutes.
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