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Analyse of photovoltaic solar cells by the photoluminescence method
Baura, Tomáš ; Bača, Petr (referee) ; Vaněk, Jiří (advisor)
This thesis deals with the analysis of solar cells by photoluminescence method. Photoluminescence method is based on the excitation of luminescence radiation of the solar cell material by an external excitation light source. This method can detect various types of defects in the material solar cells. The main objective is the design and realization of a measuring system defects of solar cells, which is based on this method. For excitation of luminescence is used LED array. For the detection of luminescence is used CCD camera with IR optical filter. To filter out the excitation light radiation is used disc screen and optical interrupter. The parameters and options of this measuring system are verified and characterized by test measuring for example the achievable rotation speed of screen and response of optical interrupter. At the end is tested detection of luminescence radiation of solar cells in the measuring system. The measured images are compared with the method of electroluminescence.
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Inovation of measurement equipment used for analyzing of photovoltaick cells
Otépka, Jakub ; Bača, Petr (referee) ; Vaněk, Jiří (advisor)
This bachelor thesis deals with the design of a tachometer which is used to measure and display of mechanical aperture speed of a measuring equipment for the defect analysis of solar cells using the photoluminescence method. This work is divided into three parts. The first section describes the principle of solar cells, the principle of luminescence radiation and its types. Next the defects of solar cells are analyzed. The second part discusses the theory of tachometers, the principles and methods of loading pulses. The third part is then analyzed the design and construction of the selected type tachometer.
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Photoluminiscence study of thin layers of MoS2
Kuba, Jakub ; Kunc,, Jan (referee) ; Bartoš, Miroslav (advisor)
The thesis deals with study of thin layers of transition metal dichalcogenides, especially of molybdenum disulfide. Nanostructures were fabricated on two-dimensional crystals of MoS2 and WSe2. Within followed analysis attention was paid to the photoluminescence properties. In the thesis transition metal dichalcogenides are reviewed and description of the modified process of preparation by micromechanical exfoliation is given.
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Analyse of photovoltaic solar cells by the photoluminescence method
Richter, Vladimír ; Bača, Petr (referee) ; Vaněk, Jiří (advisor)
This diploma thesis deals with the issues of photovoltaic cells. The main aim of this thesis is to introduce the principles of operation of solar cells and methods of detection of defects affecting their quality. The first part is about the functional properties of silicon cells and it also examines the possibilities of detecting the defects of these structures. It also describes the most commonly used modern diagnostic methods. In the next part, practical tests of photovoltaic cells using the methods electroluminescence and photoluminescence are performed. These methods are based on the excitation of luminescence radiation of the silicon material by the external light source.
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Diagnostic method of solar cells operating at very low temperatures
Bartoň, Jiří ; Stojan, Radek (referee) ; Veselý, Aleš (advisor)
This work deals with the modern diagnostic methods of defects detection of solar cells. Defects are detected by electroluminescence and photoluminescence methods. The main focus of this work is an innovation workplace for measuring solar cell defects at very low temperatures using photoluminescence. Liquid nitrogen is used to cooling solar cells. By using low temperatures can be detection methods to obtain more objektive results of diagnostic defects.
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Automatization of experimental setup for optical spectroscopy
Čecháček, Jan ; Nováček, Zdeněk (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with the modernization and improvement of an application that automates measurements on an experimental setup for spectral and topographic mapping using confocal microscopy and near-field microscopy. The arrangement of the report, the principle of communication of the program with individual parts of the report and the principle of data collection and processing are described here. The output of the program are point spectra and 2D maps describing the topography, intensity and position of the spectral peaks. The thesis includes a research study of optical and time-resolving optical spectroscopy and their applications in nanophotonics. The correct functionality of the program is demonstrated by the results of measurements of perovskite MAPbI3 and organic substrate.
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The equipment for control very low temperatures during the detection defects of solar cells
Stojan, Radek ; Bača, Petr (referee) ; Vaněk, Jiří (advisor)
This work deals with measuring of very low temperatures during the detection defects of solar cells by photoluminescence method. Liquid nitrogen is used to cooling solar cells. Properties of liquid nitrogen and safety of handling are described in this work. Themperature in cryo area is measured by the thermocouple senzors. A main part of this work was to concept and creation of equipment for themperature controling in cryo technique. This equipment signalling danger scorch in low temperatures. The device was created to complement work place for the detection defects of solar cells by photoluminescence method.
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Processing and properties of transparent polycrystalline ceramic materials
Tásler, Jan ; Pouchlý, Václav (referee) ; Maca, Karel (advisor)
The presented diploma thesis is focused on the preparation and properties of transparent polycrystalline ceramic materials based on Al2O3. Theoretically, the most important technological aspects of the processing of these materials are presented. Detailed attention is given to transparent Al2O3 polycrystalline ceramics doped with rare earth elements. The influence of microstructural parameters on the optical properties (represented by RIT) is investigated on Al2O3 samples doped and codoped with dysprosium, terbium and chromium. A significant effect of the average grain size on the light transmittance of all samples is observed. The highest RIT = 55 % (measured by a laser beam with a wavelength of 632,8 nm) was achieved by an optimized preparation process for a sample doped with 0,05 at. % of dysprosium. For all samples photoluminescent properties are also analysed. The photoluminescent emission spectra correspond to the activation of doping elements. In case of the terbium and chromium codoped samples, the differences in the activation of individual dopants depending on different excitation wavelengths were demonstrated, resulting in different colour emissions for different excitation wavelengths.
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Automatisation of an experimental setup for optical spectroscopy
Hrabina, Jakub ; Gallina, Pavel (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with the development and description of an application that enabled full automation of an experimental assembly for spectral mapping using confocal optical microscopy. It presents communication with all individual devices and explains the principle of data collection from the examined sample and their subsequent mathematical processing. The output of this application is the visualization of 2D spectral maps evaluating the intensity and position of spectral peaks, with the possibility of exporting user-friendly point spectra. In addition, the work further describes a research study of optical confocal spectroscopy with applications to nanophotonics. In addition, the functionality of the whole application is demonstrated on the spectral response of a 2D metasurface, which acts as a Bayer mask.
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Optical characterization of perovskite nanostructures
Urban, Jakub ; Kvapil, Michal (referee) ; Dvořák, Petr (advisor)
The present bachelor's thesis focuses on the optical characterization of CsPbBr3 nanocrystals ranking among the group of materials called perovskites which are remarkable for their high photoluminescence (PL) quantum yield. An algorithm for a correlation of experimental data measured by PL mapping with morphological and topological properties obtained by using Scanning Electron Microscopy and Atomic Force Microscopy has been developed which clears the way for a particular crystal detection and their spectrum analysis. Specifically, crystals the shape of which can be approximated by a cuboid have been detected and the volume dependence of the centre of mass of their PL, which is proportional to V^(-2/3) as predicted by the theorethical model, has been discovered. The measurement of PL dependency on temperatures ranging from 40 to 60 °C has also been conducted and in this temperature interval linear dependence of the full width at half maximum of their PL spectral line that rises with rising temperature has been confirmed. On the contrary, the centre of mass of PL has been found to be temperature independent.
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