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Preparation of low-dimensional inorganic perovskites
Nedvěd, Matěj ; Dvořák, Petr (referee) ; Musálek, Tomáš (advisor)
This bachelor thesis deals with the perovskite CsPbBr3. The thesis presents properties and different ways of preparing nanostructures of this inorganic perovskite. The emphasis is placed on physical vapor deposition using effusion cells. The experiments carried out to prepare nanocrystals and nanowires and the subsequent analysis of their morphology, composition and optical properties are described. The effect of the electron beam and long-term exposure to air on the optical properties is studied. Also, the concept of an experiment that should result in the replacement of lead in the perovskite structure by tin is presented.
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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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Conducting polymers and their use in supercapacitors
Gottwald, Tomáš ; Zatloukal, Miroslav (referee) ; Dvořák, Petr (advisor)
This work deals with the issues of using conducting polymers for supercapacitor electrodes and optimizing the technological process for their production. The work focuses on optimizing the amount of polymer used in order to achieve the most capacity. The methodology consists of creating an appropriate experimental electrode and subsequent measuring its associated capacity with BioLogic. This approach leads to creating charts which show the dependencies of capacity on the amount of polymer used.
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Evaluation of Business Performance Through Financial Analysis Tools
Veselý, Tomáš ; Dvořák, Petr (referee) ; Ptáček, Roman (advisor)
The topic of this bachelor thesis is „Evaluation of the efficiency of the company using financial analysis tools“. This bachelor thesis deals with evaluation of the financial situation of the company TOS Znojmo a.s., which is focused on development, production and sale of transmission equipment. The thesis is divided into three parts. The first part is focused on principles financial analysis and its use in practice. In the second part is made an analysis of the chosen company and in the third part there will be determined measures and proposals for improvement of financial situation based on the results of financial analysis.
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Interaction of a SNOM tip with electromagnetic near-field produced by interference of surface plasmon polaritons
Jakub, Zdeněk ; Břínek, Lukáš (referee) ; Dvořák, Petr (advisor)
The aim of this bachelor’s thesis is fabrication of probes for scanning near-field optical microscope (SNOM) and testing of their functionality by measuring interference patterns of surface plasmon polaritons (SPP). The theoretical part deals with the basic properties of SPP’s and methods of their excitation and detection. In the experimental part, methods of sharp tip fabrication by chemical etching, thin film deposition by ion beam sputtering (IBS) or by ion beam assisted deposition (IBAD) and aperture opening by focused ion beam (FIB) are explained and demonstrated. Finally, interference patterns of SPP’s are measured with fabricated probes and the results are compared with the results obtained with commercially available probes.
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Network Application Chess Learning
Dvořák, Petr ; Rozman, Jaroslav (referee) ; Zbořil, František (advisor)
The work deals with creating of application for teaching chess. Teaching methods include not only play against the computer, but also a network play against the player or computer. It is also created the support to use chess diagrams. The program support existing playing games in standard PGN format. A chess engine is responsible for analysis of these games and it communicates via standard Win / XBoard. The Chess engine generates alternative moves in a given position and provides the player to think about. The application also supports standard FEN. In the opening chapters of this work are discussed used tools, the basics of chess and more detail existing types of chess notation. In other parts of the work I analyze an existing individual chess standards, theirs design and theirs implementation in my program. In the rest of the work I describe designed and implemented parts of the program, such as its graphic design and supporting side panels. In the last chapter I describe the server that connects all the current players.
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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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Interaction between SNOM tip and near-field
Krpenský, Jan ; Kvapil, Michal (referee) ; Dvořák, Petr (advisor)
Interaction between a probe for scanning near-field optical microscopy (SNOM) and near electromagnetic field is a fundamental problem, with its solution being a necessary condition for the correct interpretation of experimental data. This bachelor's thesis is aiming to thoroughly describe this problem and by precise manufacturing of our own SNOM probes help to reach solution of this problem. For this purpose, the detection of near-field generated by interference of surface plasmon polaritons (SPP) on square shape nanostructures is being used. This study has proven the dependence of SNOM probe sensitivity to near-field components on the size of a SNOM aperture.
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Measurement of the local phase of metasurfaces using digital holographic microscopy
Weiss, Vlastimil ; Bouchal, Petr (referee) ; Dvořák, Petr (advisor)
This bachelor's thesis consists of research studies of optical metasurfaces that are capable of modifying and governing incident radiation via the shift of a local phase. It also discusses experimental microscopic techniques with the ability to measure the distribution of the said phase. Experimental results of the phase distribution of the electromagnetic wave impinging on metal metasurface presented in this thesis are captured through quantitative in-line and off-axis digital holographic microscopy. These metasurfaces utilize both geometrical phase and localised surface plasmon resonance (LSPR). Measured results are in accordance with previous scientific studies. Finally, the successful outcome in the form of measurement of the geometrical phase introduced by the single building block is presented as well as the application of an analytical model for characterization of phase response generated by interaction with optical metasurfaces.
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