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Preparation and characterization of thin organic photovoltaic layers
Kratochvíl, Matouš ; Zmeškal, Oldřich (referee) ; Weiter, Martin (advisor)
This bachelor thesis focuses on preparation of organic solar cells and characterization of their properties. The theoretical part consists of literature search focused on current findings in this area and basic theoretical knowledge of the mechanisms of solar cells functioning. The experimental part of the thesis deals with the preparation of solar cells, targeting large cells, and characterization of basic electrical and optical properties of these cells.
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Kinetics of photochromic reactions in thin polymeric layers
Zeman, Vojtěch ; Weiter, Martin (referee) ; Vala, Martin (advisor)
The thesis is aimed to the study of spiropyrane behavior in polymeric matrix of poly(N-vinylkarbazole) (PVK) and poly[2-methoxy-5-(3´,7´-dimethyloctyloxy)-1,4-fenylenvinylene)] (MDMO-PPV). The photochromic transformation of spiropyrane to its isomeric merocyanine form (SPMC) was studied by absorption and emission spectroscopy. It was found, that photochromic reaction is markedly dependent on the environment. In the PVK polymer, which don’t absorb in the visible region, a high yield of photochromic reaction was achieved. Both, absorption and emission spectrums were observed for this system. From the measurement of time dependencies of the fotochromic reaction, the activation energy of the reverse reaction was determined. A different behavior, particularly in emissive spectrums, was found for the MDMO-PPV polymer doped with spiropyrane. Instead of formation of new band of merocyanine, decrease of the polymer fluorescence was observed. Subsequently, we studied the interaction between the polymeric matrix and the photochromic spiropyrane using fluorescence quenching method. On the basis of energy transfer theory, a critical radius of the fluorescence quenching sphere in solution and in solid was determined.
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Study of optoelectrical properties of organic semiconductor thin film layers
Kovář, Jakub ; Weiter, Martin (referee) ; Zmeškal, Oldřich (advisor)
This thesis concerns with electrical and optoelectical properties of thin organic semiconductor layers. In the research, organic electroluminescent devices were prepared and the effect of illumination and inclusion of organic interlayers, that act as alternative electrodes, on charge injection and transport were investigated on them by means of electrical measurement and impedance spectroscopy. On the basis of measured data, the thesis attempts to determine materials best suited for interlayers, which could make an improvement of electric properties of electroluminescent devices possible. The sence of using a combination of direct current measurement and impedance spectroscopy was also discussed in the thesis.
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Advanced materials for organic electronics and bioelectronics
Šudomová, Lucie ; Márová, Ivana (referee) ; Weiter, Martin (advisor)
This bachelor thesis focuses on the characterization of organic materials with semiconductor properties in terms of their potential use in bioelectornic applications. The theoretical part is summarizing the basic characteristics of organic materials for organic electronics and bioelectronic. There are mentioned basic structures and general properties of relevant substances. This part of the thesis also describes the basic principles of devices for bioelectronic applications and its use. Practical part includes preparation of thin films of two types substances: on the basis of low-molecular organic substances (6,13-bis(triisopropylsilylethynyl) pentacene and diketopyrrolopyrrole) and another based on polymers (Poly (3-hexylthiophene-2,5-diyl) and Poly (3,4-ethylenedioxythiophene): poly (styrene sulfonic acid) and). The first part of the experiment is focused on the characterization of the properties of used substances. The second part examines microbial biocompatibility
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Organic solar cells based on polymers
Nagyová, Veronika ; David, Jan (referee) ; Weiter, Martin (advisor)
This bachelor thesis concentrates on the properties characterization of new organic materials for solar cells. In the theoretical part, there is a solar cells themed literature search, there is described a mechanism of conversion of solar energy and the structure of organic solar cells. The practical part includes the preparation of solar cells and characterization of basic optical and electrical properties of the studied materials.
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Organic solar cells based on lowmolecular materials
Omasta, Lukáš ; David, Jan (referee) ; Weiter, Martin (advisor)
This bachelor thesis is focused on characterization of new organic materials suitable for use in solar cells. In the theoretical part, there is research on organic solar cells together with description of the photovoltaic energy conversion. In this part, description of the structure and general properties of materials used to produce solar cells is given. The individual characterization methods are also described. The practical part includes the preparation of thin layers of organic materials and their optical characterization. Preparation of solar cells with classic structure is also included together with evaluation and comparison of their photoconductivity and efficiency.
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Organic solar cells
Sionová, Marcela ; Navrátil, Jiří (referee) ; Weiter, Martin (advisor)
This bachelor thesis concentrates on the properties characterization of new organic materials for solar cells. In the theoretical part, there is a solar cells themed literature search and a description of the fotovoltaic energy conversion. The practical part includes the preparation of solar cells with classic and invert structure and comparsion their efficiency on transparent electrodes from a different producers.
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Charge carrier transport in organic disordered materials
Češka, Matěj ; Navrátil, Jiří (referee) ; Weiter, Martin (advisor)
This bachelor´s thesis deals with organic materials for use in photovoltaic energy conversion. A theoretical part of this thesis contains brief introduction to organic photovoltaics. Thin organic films were prepared and were characterized by optical methods and by current voltage characteristics. It was found that the light illumination can improve conductivity of prepared thin layers.
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Organic materials for photovoltaic conversion of solar energy
Vrchotová, Jana ; Vala, Martin (referee) ; Weiter, Martin (advisor)
This bachelor´s thesis deals with new perspective organic molecular materials for use in photovoltaic energy conversion. A theoretical part of this project contains brief introduction to photovoltaics and search themed on organic photovoltaics. The aim of the experimental part was preparation of thin layers of diketopyrrolopyrrole and hemiisoxindigo derivatives and study of optical properties of solutions and thin layers prepared from these materials.
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Dye Sensitised Solar Cells
Schovancová, Petra ; Weiter, Martin (referee) ; Dzik, Petr (advisor)
Recent experimental effort is focused to a very promising photovoltaics technology – dye sensitized solar cell. This technology is based on the generation of electrons in a sensibilization dye and their separation on a semiconducting material (TiO2). Bachelor thesis deals with the summary of present knowledge about this technology, the preparation of solar cells from generaly and commercially available components and basic study of their properties.
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