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Research of organic layers for solar cells
Pečeňa, Rastislav ; Toušek, Jiří (advisor) ; Křivka, Ivo (referee)
Title: Research of organic layers for solar cells Author: Rastislav Pečeňa Department: Department of Macromolecular Physics Supervisor: doc. RNDr. Jiří Toušek, CSc., Department of Macromolecular Physics Abstract: The main object of this project is to determine some parameters of polymer layers PPV (poly(p-phenylene vinylene)), which are important for usage of solar cells. We will do that by measuring spectra of surface photovoltage, from which we can get particular parameters of material by their fitting: such as exciton diffusion length, thickness of space charge region (SCR), surface recombination velocity of excited electrons. The dependence shows where material is inducing the highest current density. Some measurements of organic materials enriched with nanoparticles will also take place. It is possible to find an approx. diameter of nanoparticles from spectral dependence of voltage. Keywords: solar cell, diffusion length, nanoparticles, organic layer
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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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Some electrical and photoelectrical properties of organic semiconductors
Chomutová, Radka ; Toušek, Jiří (advisor) ; Křivka, Ivo (referee)
Title: Some electrical and photoelectrical properties of organics semiconductors Author: Radka Chomutová Department: Department of Macromolecular Physics Supervisor: doc. RNDr. Jiří Toušek, CSc., Department of Macromolecular Physics Abstract: The object of this study is to determine some electrical and photoelectrical properties of polymer materials and their importance considering their usage as a solar cell. Especially, thin layers of polythiophene (PT1,PT2) and poly-3-hexylthiophene (P3HT) are measured and determined. Studied parameters are Fermi level by Kelvin method, the concentration of free charge carriers, conductivity, exciton diffusion length and thickness of the space charge region by surface photovoltage method (SPV). Obtained values were then added to older measurements with similar focus for polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4- phenylenevinylene] (MEH-PPV). Keywords: sollar cell, diffusion lenght, surface photovoltage method, Kelvin probe, organic layer
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Research of organic layers for solar cells
Pečeňa, Rastislav ; Toušek, Jiří (advisor) ; Křivka, Ivo (referee)
Title: Research of organic layers for solar cells Author: Rastislav Pečeňa Department: Department of Macromolecular Physics Supervisor: doc. RNDr. Jiří Toušek, CSc., Department of Macromolecular Physics Abstract: The main object of this project is to determine some parameters of polymer layers PPV (poly(p-phenylene vinylene)), which are important for usage of solar cells. We will do that by measuring spectra of surface photovoltage, from which we can get particular parameters of material by their fitting: such as exciton diffusion length, thickness of space charge region (SCR), surface recombination velocity of excited electrons. The dependence shows where material is inducing the highest current density. Some measurements of organic materials enriched with nanoparticles will also take place. It is possible to find an approx. diameter of nanoparticles from spectral dependence of voltage. Keywords: solar cell, diffusion length, nanoparticles, organic layer
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Financial analysis of RETAL Czech, a.s.
Strachotová, Michaela ; Slunčík, Peter (advisor) ; Křivka, Ivo (referee)
The aim of the Bachalor's thesis is to analyze the real financial situation of RETAL Czech, a.s during the period 2006 -- 2010 with the help of the most widely used methods of financial analysis, compare it to competitor and the branch. The thesis is divided into 2 parts, theoretical and practical. In the theoretical one are described methods which are used in practical part. Practical part contains real dates, usage of methods from theoretical part and comparison with competitor. In conclusion is summary of my analysis including my recommendation.
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