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Preparation of perovskite solar cells with regular n-i-p architecture and their optimization
Poláková, Simona ; Zmeškal, Oldřich (referee) ; Pospíšil, Jan (advisor)
The diploma thesis deals with the study of perovskite solar cells with a regular n-i-p architecture. The theoretical part of this work is mainly focused on the stability of perovskite solar cells, i.e. thermal stability and the influence of UV radiation on final perovskite solar cell stability. Furthermore, the deposition methods, the architecture of solar cells and the materials used for the preparation of electron and hole transport layers were described in more detail. The experimental part deals with the optimization of the preparation of perovskite solar cells (especially in terms of resulting photovoltaic conversion efficiency), with a description of the structure preparation process of the final photovoltaic cell and the interpretation of the measured results.
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Perovskite single crystals for the detection of electromagnetic radiation
Gavranović, Stevan ; Novák, Vítězslav (referee) ; Pospíšil, Jan (advisor)
This thesis is focused on the study of the detection of electromagnetic radiation using monocrystalline perovskites. Theoretical part deals with basic principles of detections and possible applications of hybrid perovskite crystals in the field of ultraviolet and visible spectrum detection. Parameters of the recently published perovskite photodetectors are also presented. Experimental part describes synthesis, structural and optical properties of MAPbBr3 single crystals and electrical characterization of the Au/MAPbBr3/Au photodetector. Photodetector parameters (responsivity, external quantum efficiency and specific detectivity) are calculated based on the spectral and switching (on/off) current responses.
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Retaining Walls
Pospíšil, Jan ; Boštík, Jiří (referee) ; Glisníková, Věra (advisor)
The objective of thesis is to create a comprehensive overwiew of the most commonly used retaining walls in the Czech Republic and to characterize their properties, method of assessment, advantages, disadvantages or causes of failures. Based on these findings will be designed selected type of retaining wall in Rebešovice.
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Preparation and characterization of perovskite solar cells
Juřík, Karel ; Salyk, Ota (referee) ; Pospíšil, Jan (advisor)
This work deals with the perovskite photovoltaic cells. The first part summarises the basic information about this technology and shows the most important milestones in its development. Following part includes the parameters required to characterise the electric properties of a photovoltaic cell and the assessment of its quality. The experimental part of this thesis aims to describe the influence of the annealing time of the perovskite active layer on the final efficiency of created solar cells. The best results were determined to be achieved with the annealing time of 90 minutes.
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Housing+
Mikulová, Marie ; Pospíšil, Jan (referee) ; Sládeček, Svatopluk (advisor)
The core focus of this project is the solution of the land planning in the area of Tomkovo náměstí in Brno near the Velký městský okruh. It deals with the impact of the circuit’s dual carriageway on the surrounding environment and offers how to integrate this transport structure into the newly built area as well as into the original urban area. The solution includes a composition of objects designed either in a form of permanent living space or a hostel, all with the addition of an outside marketplace.
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Passivation of the active layer in perovskite solar cells with inverted architecture
Babincová, Kristina ; Zmeškal, Oldřich (referee) ; Pospíšil, Jan (advisor)
The topic of this work is the passivation of the active layer of perovskite solar cells with an inverted structure. The work is divided into theoretical and experimental part. The theoretical part describes in particular the passivation and modification of the perovskite layer as well as the characteristic properties of perovskite, including structure and stability. The experimental part deals with the preparation of photovoltaic cells with an inverted structure. For the characterization of photovoltaic cells, reference samples were prepared and their active layer was modified by plasma. The most used deposition technique for the preparation of layers was the spin coating method. From the performed experiments it can be concluded that the preparation of samples and their subsequent modification under laboratory conditions does not lead to the improvement of the final parameters of photovoltaic conversion. By transferring the sample preparation and passivation of the active layer to an inert atmosphere, it was possible to produce cells with higher efficiencies (compared to the reference sample), around 10 %. Another advantage of this plasma treatment of the active layer is that it also improves the stability of the prepared structures, which even after a few days in air show almost 80 % of the original efficiency.
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Study of the dielectric properties of perovskite crystals
Mlčkovová, Hana ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
The presented diploma thesis deals with the preparation of perovskite single crystals by inverse thermal crystallization and subsequent study of the basic properties of these hybrid organic-inorganic materials that can be used in various optoelectronic (photodetectors, transistors, lasers, LEDs) or photovoltaic applications. Their behavior in the electric field was studied by impedance spectroscopy. Impedance and capacitance-voltage (C-V) characteristics (frequency dependences) were measured in the dark and in the light. From the impedance dependences for measurements at 0 V voltage in the dark, the equivalent circuit was modeled and its parameters and dielectric constant were determined. From the C-V dependence, Mott-Schottky analysis determined the parameters – "flat-band" potential U_"fb" and charge carrier density N_"C-V" , the parameter – the so-called Warburg coefficient was found, which together with the parameter N_"C-V" was used to calculate the diffusion coefficient D.
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Virtualized web application for receiving data from sensors
Kharytonov, Oleh ; Fujdiak, Radek (referee) ; Pospíšil, Jan (advisor)
At the beginning of the theoretical part, the bachelor thesis focuses on LPWAN or Low-Power Wide-Area Network technology. Systems that are characterized by low power consumption and wide coverage. Their key features are discussed. Subsequently, attention is paid to the LoRaWAN\texttrademark\ standard,. Initially, LoRa\textsuperscript{\tiny\textregistered} modulation is discussed - the modulation techniques used and the advantages over competitors. The next step discusses LoRaWAN\texttrademark\, - architecture, types of end devices and security. Virtualization - uses in today's world, discusses types of virtualization and its benefits. The practical part introduces the commissioning of open-source LoRaWAN\texttrademark\, ChirpStack server, gateway, endpoint registration and activation. Attention is paid to an application programmed using Flask for device management and data reception. The principle of operation and commissioning of the virtualized web application is explained. Finally, the results and possible ways to improve the application are described.
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