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Characteristics Of Gallium Arsenide Solar Cellsat High Temperature
Papež, Nikola
This article reviews a work on processing of gallium arsenide (GaAs) solar cells. The performance of the cells before and after 300 _x000E_C thermal processing was correlated with topography identified by optical camera, atomic force microscope (AFM) and scanning electron microscope (SEM). Experiment indicates insignificant changes in topography of GaAs solar cells, but electrical characteristics show an excellent resistance of the samples to processing temperature.
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Advanced Structural Analysis Of Silicon Solar Cells
Papež, Nikola
The study investigates the structural imperfections of photovoltaic cells based on polycrystalline silicon. Experimental characterization focuses in particular on the degradation and defects analysis. Two modern techniques were used – scanning electron microscopy (SEM) with electron beam induced current (EBIC) and 3D digital optical microscopy. The properties and range of cell defects that can significantly affect its function were characterized with this inspection and failure Analysis.
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Properties of solar cells based on polymer-silicon junction
Pavlovič, Dean ; Toušek, Jiří (advisor) ; Křivka, Ivo (referee)
Title: Properties of solar cells based on polymer-silicon junction Author: Dean Pavlovič Department / Institute: Department of Macromolecular Physics Supervisor of the bachelor thesis: doc. RNDr. Jiří Toušek, CSc, Department of Macromolecular physics Abstract: The aim of this work is to study unconventional materials, namely conjugated polymers, as to be used for photovoltaic purposes. Among these polymers are polyaniline, derivative of polyphenylene vinylene and two derivatives of polythiophene. Four different methods are used to study some of the physical quantities of the samples, that should affect overall efficiency of solar power conversion. Firstly, I-V characteristics yields fill factor and indicates mechanism of charge transport. Method based on surface photovoltage (SPV) estimates diffusion length of the charge carriers - excitons. Impedance spectroscopy and particular method abbreviated CELIV both measure charge carrier mobility. Outcome of this work are the values of these quantities for some of the samples. Keywords: organic semiconductors, solar cells, mobility, diffusion length, current-voltage characteristic
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Microstructural Defects of Solar Cells Investigated by a Variety Diagnostics Methods
Škvarenina, L’ubomír
This paper discusses the application of a variety diagnostic methods applicable to the solar cells. More objective results about solar cells quality and reliability are possible to obtain by using a various methods. Diagnostic methods described in this paper are based on a dark and illuminated J–V characteristics, a investigation of noise in a wide range of frequency and a radiation detection at a di erent spectral range, namely by an electroluminescence and a thermography method. These methods are primarily more appropriate for a detection or a localization of microstructure defects when a reverse-bias stress is applied. However, the analysis of a forward-bias conditions is included in an investigation of J–V characteristics as well.
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Silicon solar cells: methods for experimental study and evaluation of material parameters in advanced structures
Holovský, Jakub ; Vaněček, Milan (advisor) ; Sládek, Petr (referee) ; Hlídek, Pavel (referee)
This work concerns with today's challenges of photoelectrical characterization methods in the research and development of thin film silicon solar cells. Relevant results are obtained only when photocurrent spectroscopy and measurement of current-voltage characteristics, are applied on the real structures that can however be multi-layered, multi-junction devices with nanostructured interfaces. Analytical and numerical optical models comprising light scattering are used for analysis of light absorption and for evaluation of optical absorption coefficient of silicon layers in sub-gap region. The slope of absorption edge and residual absorption in mid-gap indicate material disorder and defect density. Based on the investigation of electrical interaction between sub-cells in the dual-junction solar cell we developed new methods of evaluation of photocurrent spectra and current-voltage characteristics individually for each sub-cell with no need to contact them directly. Usability of Fourier Transform Photocurrent Spectroscopy as a robust method for photocurrent spectroscopy of amorphous silicon is thoroughly analyzed here. The issues of frequency dependence are addressed in detail and comparison with photothermal deflection spectroscopy is made.
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Preparing of Grätzel solar cell
Gerlich, Jakub ; Strachala, Dávid (referee) ; Kadlec, Michal (advisor)
This bachelor thesis focuses on the problematic of the dye-sensitized solar cells. The thesis states the working principle of these cells. It also deals with the use of different types of dyes, counterelectrodes, electrolytes and conducting glass. The thesis also contains the principles used in measuring the effectivity of solar cells. The manufacturing process of these cells is described in this thesis. The practical part of the thesis is focused on the manufacture of cell prototypes and the measuring of their parameters.
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Microscopic analysis of silicon solar cells defects
Brukner, Jakub ; Solčanský, Marek (referee) ; Stojan, Radek (advisor)
This thesis deals with detection of defects solar cells using method electroluminescent, electron microscope and subsequent 3D modeling of areas with defects and structure of the solar cell. In the text are describe basic methods for detection of defects appearing in solar cells. Also some basic defects which can be made during manufacture are there describe. For better orientation the basic principle of functionality and manufacturing process is included.
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High Temperature Processes in Silicon Solar Cells Production
Frantík, Ondřej ; Hudec, Lubomír (referee) ; Banský,, Juraj (referee) ; Szendiuch, Ivan (advisor)
The thesis is focused on high temperature processes in crystalline solar cells production. Main topic is diffusion of traditional dopants phosphorus and boron. Diffusion processes for creating solar cells are different from classical diffusion in semiconductor industrial. It is reason why the thesis describes crated layers in detail. Knowledge of diffusion processes is used for creating bifacial solar cells and development of a new phosphorus emitter for conventional solar cells. Bifacial cells are a new type of cells. Developed new emitter increases efficiency and decreases cost of solar cells production. Another part the thesis is devoted to the prediction of diffusion processes. New models of phosphorus and boron diffusion for photovoltaic industrial are created in software SILVACO. Models correspond with real results.
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Organic semiconductors
Tebich, Ivan ; Macháček, Martin (referee) ; Boušek, Jaroslav (advisor)
My final thesis treats of usage photovoltaic phenomenon to production electric energy by solar cells. It inquires into this phenomenon in organic structures. Further it mentions basic types of constructions organic solar cells and evaluates their properties. In experimental part zhe thesis is focused on characterization thin-film structures made out of photoconductiv organic materials.
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