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Preparation and charakterization of WO3 layers by brick and mortar method
Blecha, Tomáš ; Pekárková, Jana (referee) ; Králová, Marcela (advisor)
This master’s thesis deals with thin films of tungsten trioxide, which are prepared by combining nanoparticles and a binder. The composite consisted of either milled WO3 nanoparticles of different sizes or the combination of milled nanoparticles and dopamine stabilized peroxotungstic acid. The prepared compositions with the addition of templating agent polyethylene glycol were deposited on conductive FTO glass by spin coating method and further used as a photoanode in a photoelectrochemical cell. This work then focuses on studying the influence of the milled particle size and the amount of binder in the composition on the physicochemical properties of WO3 photoanodes in an attempt to measure the highest photocurrrents.
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Fabrication and properties of photocatalyst layers with controlled porosity
Blecha, Tomáš ; Gemeiner, Pavol (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with fabrication of photocatalyst layers with controlled porosity and investigation of their properties. Polyvinyl pyrrolidone, polyethylene glycol and polyvinyl alcohol were used as templating agents. Prepared compositions were deposited on FTO glass using a drop-casting method and annealed at 450 °C. The structure of thin films was examined using optical and electron microscopy. The thin films were subsequently studied by photoelectrochemical measurements. Most resulting compositions showed relatively good electrical and optical properties, hinting at a potential for future use in practice.
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Tungsten trioxide coatings fabricated from nanocrystalline suspension and binder
Filipská, Markéta ; Zlámal,, Martin (referee) ; Dzik, Petr (advisor)
This diploma thesis deals with layers of tungsten oxide, which are prepared from a nanoparticle suspension and a binder. The coating composition consisted in the first case of ground tungsten oxide nanoparticles alone, then of acetylated peroxotungstic acid alone and finally of a mixture of ground tungsten oxide mixed with acetylated peroxotungstic acid. The compositions thus formed were applied to conductive FTO glass and thus act as photoanodes. A stainless steel needle is used as a counter electrode for volt-ampere measurements. The work focuses on the study of physicochemical properties of prepared photoanodes and their optimalization in order to obtain the highest possible values of generated photocurrents. The electrical properties of all cells were determined using voltammetric characteristics.
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Synthesis and properties of tungsten tioxide layers fabricated by the sol-gel process
Hesková, Helena ; Pekárková, Jana (referee) ; Dzik, Petr (advisor)
This work deals with the optimization of the preparation process of WO3 layers by the sol-gel method and their properties. Several precursor solutions were prepared which were applied to the substrate by spin-coating and drop-casting. The deposited layers were annealed at 450°C until complete degradation of the polymer matrix contained in the precursor. The structure of the layers was observed by scanning electron microscopy, their composition by the X-ray diffraction and their thickness was determined by profilometry. The properties of the prepared layers were also investigated by photoelectrochemical measurements.
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Fabrication and characterization of tungsten trioxide photoanodes
Hesková, Helena ; Králová,, Marcela (referee) ; Dzik, Petr (advisor)
This work deals with the optimization of the preparation process of WO3 photoanodes nad their characterization. For compositions were prepared, which were applied to a substrate via spin-coating process and subsequently annealed at 450 °C. The length of milling of precursor particles contained in the coating formulations determined properties of deposited layers. were examined for. The additivity of the individual compositions was also observed. The structure of the layers was observed by optical microscopy and scanning electron microscopy (SEM), their composition by the X-ray diffraction (XRD) and their thickness and surface roughness was defined by contact profilometry. Photoelectrochemical properties of the prepared layers were also investigated by linear voltametry and chronoamperometry.
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Semiconductive gas sensors for detection of organic gases and vapours
Šedivý, Matúš ; Gablech, Evelína (referee) ; Gablech, Imrich (advisor)
This bachelor thesis is focused on gas sensors. Basic characteristics of sensors are discussed in the first part. Next part contains an overview of the most used types of gas sensors based on different physical principles. The main aim of thesis outlines last chapter where process of making gas sensors with different semiconductive metal oxides active layers is described. This thesis also describes measuring of their characteristics and characteristics of commercial gas sensor TGS 822 made by Figaro. Measured data are processed in graphs and tables and then were used for comparison with created sensors. In conclusion, there are discussed possibilities of improving selectivity of gas detection by using sensors with different active layer.
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Printed photoelectrochemical sensor for blue light
Papák, Jiří ; Hatala,, Michal (referee) ; Dzik, Petr (advisor)
This diploma thesis focuses on electrochemical sensors to detect radiation in the blue region of the visible spectrum. As a semiconducting material for the manufacture of the sensor, a suspension of tungsten trioxide was found. The individual elements of the sensor were applied by pad printing techniques or screen printing. Using linear voltammetry and chronoamperometry, the magnitude of the generated current was measured and radiometric calibration was performed. The properties of the layers were characterized by profilometry, optical and electron microscopy.
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Tungsten Trioxide Thin Films Deposited by Material Printing of Aqueous Precursors
Martinková, Eliška ; Pekárková, Jana (referee) ; Králová, Marcela (advisor)
This bachelor thesis deals with material printing of thin layers of tungsten trioxide with selected templating agents. Polyvinyl pyrrolidone, polyoxyethylene(20)cetyl ether, polyethylene glycol and Pluronic 123 were used as templating agents. These compositions were applied by the material printing method on FTO glasses and annealed at 500 °C. The structure and thickness of thin films were analyzed using a profilometer, SEM and AFM. Subsequently, the properties of thin films were studied using photoelectrochemical measurements.
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Fabrication and properties of photocatalyst layers with controlled porosity
Blecha, Tomáš ; Gemeiner, Pavol (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with fabrication of photocatalyst layers with controlled porosity and investigation of their properties. Polyvinyl pyrrolidone, polyethylene glycol and polyvinyl alcohol were used as templating agents. Prepared compositions were deposited on FTO glass using a drop-casting method and annealed at 450 °C. The structure of thin films was examined using optical and electron microscopy. The thin films were subsequently studied by photoelectrochemical measurements. Most resulting compositions showed relatively good electrical and optical properties, hinting at a potential for future use in practice.
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Tungsten trioxide coatings fabricated from nanocrystalline suspension and binder
Filipská, Markéta ; Zlámal,, Martin (referee) ; Dzik, Petr (advisor)
This diploma thesis deals with layers of tungsten oxide, which are prepared from a nanoparticle suspension and a binder. The coating composition consisted in the first case of ground tungsten oxide nanoparticles alone, then of acetylated peroxotungstic acid alone and finally of a mixture of ground tungsten oxide mixed with acetylated peroxotungstic acid. The compositions thus formed were applied to conductive FTO glass and thus act as photoanodes. A stainless steel needle is used as a counter electrode for volt-ampere measurements. The work focuses on the study of physicochemical properties of prepared photoanodes and their optimalization in order to obtain the highest possible values of generated photocurrents. The electrical properties of all cells were determined using voltammetric characteristics.
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