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Adaptation of the time resolved optical spectroscopic aparatus
Koutný, Jan ; Šedina, Martin (referee) ; Vala, Martin (advisor)
The theme of the bachelor's thesis is an assembling of an apparatus for measurement of transient absorbance by flash photolysis and a testing its functionality by detecting of benzophenon triplet states absorbance. The theoretical part focuses on basic principles of optic spectroscopy, flash photolysis and an instrumentation used in spectroscopy. Special attention was paid to the components used for constructing of the experimental apparatus. The practical part concentrates on a realization of the apparatus itself, a testing of basic experimental dependences and a determining of time dependence of transient absorbance of triplet states.
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Interaction between amphiphilic fluorescent probes and hyaluronan
Střondalová, Hana ; Vala, Martin (referee) ; Mravec, Filip (advisor)
This bachelor thesis dealt with studying the interaction of amphiphilic fluorescent probes with hyaluronan because these probes could significantly help in clarifying the links between hyaluronan and surfactants. This complex could be a great benefit in targeting drug distribution. This thesis was focused on the interaction between hyaluronan and amphiphilic fluorescent probes – specifically with dodecylacridine orange. First explored was the interaction with hyaluronan, and then with the hyaluronan – surfactant system. Cetyltrimethylamonium bromide was selected as surfactant. Samples were examined using fluorescence spectroscopy. Emission and absorption spectrum of dodecyl acridine orange was measured. This experiment was based on the hypothesis that dodecylacridine orange forms dimers as acridine orange and nonylacridine orange. It was found that in a system of hyaluronan-probe, dodecyl acridine orange was pushed out of the complex by cetyltrimethylamonium bromide, which was bounded instead. Surfactant interacts with hyaluronan binding positions - with carboxyl groups.
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Microviscosity probes in study of aggregation in a biopolymer-surfactant system.
Vašíčková, Kamila ; Vala, Martin (referee) ; Mravec, Filip (advisor)
The effect of cationic surfactant concentration and ionic strength on anisotropy of fluorescence of probes diphenylhexatrien and fluorescein has been investigated in the system of cationic surfactant and in the system of cationic surfactant and hyaluronan. The investigation has been done by fluorescence emission spectroscopy. Obtained anisotropy gives information about microviscosity of investigated systems. Subsequently the system of cationic surfactant and hyaluronan has been investigated by 9-(2-carboxy-2cyanovinyl)julolidine, 4-(dicyanovinyl)julolidine and 1,3-bispyrenylpropane probes. The information about the microviscosity of the system gives the integral under the emission curve of 9-(2-carboxy2-cyanovinyl)julolidine and 4-(dicyanovinyl)julolidine and the ratio between excimer and monomer of 1,3-bispyrenylpropane. It has been discovered that the ionic strength influences the anisotropy of diphenylhexatrien and fluorescein only in the fist addition of salt (concentration 0,025 mol dm-3) and that addition of hyaluronan influences the anisotropy of diphenylhexatrien and fluorescein only in samples without addition of salt. Results of measurment with 9-(2-carboxy2-cyanovinyl)julolidine and 4(dicyanovinyl)julolidine describe the formation of aggregates of catinoc surfactant with hyaluronan and characterize these aggregates from the point of microviscosity.
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Study of electrical properties of thin polymer films
Pospíšil, Jan ; Vala, Martin (referee) ; Zmeškal, Oldřich (advisor)
The thesis is focused on the study of electric and dielectric properties of thin-film organic materials that can be used as an active layer of photovoltaic cells. Primarily were studied the properties of the layers on the PET or glass substrate, which consist of a thin active layer of polymethylphenylsilane (PMPSi) or derivatives of diketopyrrolpyrrole (DPP). On a selected sample were first measured current-voltage characteristics and current dependences on time at constant voltage (relaxation characteristics). Finally were measured frequency dependences (impedance spectra) and their relaxation characteristics too. The measured data were evaluated using the methods of fractal analysis in HarFA. The results will be used to optimize the properties of photovoltaic cells.
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Luminescence of organic materials for advanced applications
Dozbaba, Jaroslav ; David, Jan (referee) ; Vala, Martin (advisor)
The thesis deals with study of the radiation recombination of excited states in organic materials, induced by optical and electrical excitation. These processes are studied by optical spectroscopic methods and characterization of electroluminiscence. The theoretical part contains search and summary of basic knowledge necessary for interpretation of data focusing on the fluorescence of organic substances. The conversion processes of electric energy to an electromagnetic radiation in organic electroluminiscence diods were also discussed in the thesis. The practical part describes preparation of model diods, the study of their optical properties and characterization of their electroluminescence.
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Morphology study of organic molecular compounds thin films
Schön, Martin ; Vala, Martin (referee) ; Salyk, Ota (advisor)
This thesis deals with morphology study of organic molecular thin film compounds. The vapour deposition was used for thin films preparation. There are described used vacuum technology and measuring instruments in the theoretical part. In the second part is then described the experiment. The characteristics and morphology of thin films have been analyzed by scanning electron microscope (SEM). Influence of deposition temperature and distance between substrate holder and evaporator boat on film morphology have been analyzed. Diketopyrrolopyrrole (DPP) thin films have interesting chemical and physical properties, expecting wide range of applications, especially in electronics industry.
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Organic materials for photovoltaic conversion of solar energy
Vrchotová, Jana ; Vala, Martin (referee) ; Weiter, Martin (advisor)
This bachelor´s thesis deals with new perspective organic molecular materials for use in photovoltaic energy conversion. A theoretical part of this project contains brief introduction to photovoltaics and search themed on organic photovoltaics. The aim of the experimental part was preparation of thin layers of diketopyrrolopyrrole and hemiisoxindigo derivatives and study of optical properties of solutions and thin layers prepared from these materials.
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Study of humic and fullvic acids by excitation emission matrix method
Enev, Vojtěch ; Vala, Martin (referee) ; Fasurová, Naděžda (advisor)
A bachelor thesis was focused on fluorescence measurement by emission-excitation matrix method (EEM) and finding of the main fluorophores of soil humic and fulvic acids samples. The results of the position of the main peak of fulvic acid isolated from soil type Cambisol were compared and were similar to the position of Elliot soil FA standard II. For determining of secondary peaks of fulvic acids the synchronous method (3D SFS) at lower wavelengths was used.
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Optické a elektrické přepínání v organických polovodičích
Vala, M. ; Weiter, M. ; Nešpůrek, Stanislav ; Zmeškal, O.
The work deals with tuning of electro-optical properties of polymeric media using reversible light-driven switching of photochromic spiropyran guest molecules. The significant change of dipole moment during the photochromic conversion allows construction of simple switching units. Optical responses of such devices were studied using absorbance and photoluminescence, electrical responses, were detected by impedance measurements.
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