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Optoelectronic characterization of perovskite materials and their application in photovoltaics
Ulč, Filip ; Konečný, Martin (referee) ; Klok, Pavel (advisor)
This bachelor's thesis is focused on a detailed correlative study of optoelectronic perovskite materials through advanced measurement techniques employed at the Institute of Physical Engineering. These techniques include surface charge measurement and time-resolved photoluminescence mapping. Currently, there are few publications or articles attempting to analyze optical and electrical processes using more than two techniques simultaneously. Therefore, the aim of this thesis is to expand the knowledge of existing techniques and enhance them by incorporating surface charge analysis (in the dark and under illumination) using Kelvin Probe Force Microscopy (KPFM). The contribution of this work to the study of perovskite materials lies in correlative measurements that provide new insights into the arrangement and movement of charge carriers, which can be utilized in the research of perovskite solar cells.
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Model of electric charge transport in perovskites and their precursors
Raška, Vilém ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
Thesis focuses on analysis and determination of basic electric properties of perovskite materials. Thesis includes theoretical section which discusses electric properties and charge transport in solid materials. In the experimental section several chloride and boride perovskite material samples are used for measurement of VA characteristics and Impedance Spectroscopy. Then based on acquired data multiple models are created which are then used to determine required properties and state distribution of samples.
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Time changes of the photovoltaic cells properties
Kvapil, Jakub ; Vaněk, Jiří (referee) ; Novák, Vítězslav (advisor)
The thesis is about the problematics of perovskite, production of perovskite structure and measurment of photovoltaic cells. The introduction deals with material properties and sctructure of perovskite. There is explained a problem of perovskit photovoltaic cells and production of perovskite structure. Then the measurement methods are explained, which are used for evaluation of photovoltaic cells properties.
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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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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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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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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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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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Rheological properties of gels for Pechini syntheses
Wirthová, Michaela ; Ptáček, Petr (referee) ; Zmrzlý, Martin (advisor)
This work deals with preparation of layers of ceramic materials – perovskites. The introductory part includes general characteristics concerning structure, properties and use of this materials. In details then there is described method of their preparation, namely Pechini´s syntheses, which are most widely used. Optimum molar ratio of components is discussed, in the sense of what compositions lead to creation of perovskite structures. Influence of this parameter on rheological properties of precursory gels is described in the end of the first part of work. In experimental section there are described preparations of gels, which are prepared via reaction between citric acid and ethylene glycol and gels, which are prepared by Pechini´s synthesis. Rheological properties of prepared gels (density, viscosity and surface tension) and besides determination of amount of nitrates in gels are characterized. Temperature dependence of viscosity of gels, that are prepared by reaction of citric acid and ethylene glycol are determined. In final part successful preparations of perovskite layers is shown on ceramic substrate. This layers are observed by means of light optical microscope and scanning electron microscope.
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