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Low-molecular materials for organic electronics and photonics
Češka, Matěj ; Salyk, Ota (referee) ; Weiter, Martin (advisor)
This master´s thesis deals with organic materials for use in electronics and photonics. Attention was paid to low molecular weight materials. The theoretical part of this thesis contains brief introduction to organic electronics and photonics. In particular, organic transistors, organic solar cells and organic light-emitting diodes are mentioned. The experimental part is focused on study of electrical and optical properties of two types of phthalocyanines. Thin films and solutions of phthalocyanines were characterized by UV-VIS spectroscopy. Thin films were also characterized by current voltage characteristics, spectral response measurement of photocurrent and by method of transient photoconductivity. It was found that illumination affects the electrical properties of thin layers of phthalocyanines, the performance of the prepared thin films depends on the type phthalocyanine and also depends on the thickness of the layer.
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Electrical transport properties of molecular materials for smart applications
Ivancová, Anna ; Vala, Martin (referee) ; Přikryl, Radek (advisor)
This master´s thesis deals with possibilities of application of new organic molecular materials for electronic devices. Nowadays it is a very attractive field of research, because of the tendencies in industry to miniaturize, reduce production costs and develop new, eco-friendlier, processes of production. The theoretical part of the thesis provides a short overview of organic materials suitable for smart applications and thin films issues including their characterization. The experimental part is dedicated to means how to prepare thin-film electronic components to silicon wafers for thin films field effect transistors. The obtained results in the last part of thesis are discussed about properties of prepared thin films, in the concrete about the electrical transport properties, in the connection with the condition of preparation.
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Charge carrier transport in organic disordered materials
Češka, Matěj ; Navrátil, Jiří (referee) ; Weiter, Martin (advisor)
This bachelor´s thesis deals with organic materials for use in photovoltaic energy conversion. A theoretical part of this thesis contains brief introduction to organic photovoltaics. Thin organic films were prepared and were characterized by optical methods and by current voltage characteristics. It was found that the light illumination can improve conductivity of prepared thin layers.
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Preparation of fluorescent phthalocyanines for labeling of oligonucleotide probes IV.
Mikula, Daniel ; Miletín, Miroslav (advisor) ; Zitko, Jan (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department Department of Pharmaceutical Chemistry and Pharmaceutical Analysis Candidate Daniel Mikula Supervisor doc. PharmDr. Miroslav Miletín, Ph.D. Consultant Mgr. Michaela Kolářová Title of thesis Preparation of fluorescent phthalocyanines for labeling of oligonucleotide probes IV. Phthalocyanines (Pcs) are macrocyclic compounds with a conjugated system of double bonds. Thanks to this, they have interesting photophysical and photochemical properties that enable their practical use in pharmacy and medicine in the field of diagnostics or treatment of cancer diseases. This work deals with the preparation of axially disubstituted silicon complexes of phthalocyanines (SiPcs), which would have suitable properties for subsequent use in the labeling of oligonucleotide probes. The theoretical part is primarily devoted to the methods of Pcs preparation, from the choice of precursors, through the formation of the macrocycle and insertion of the central atom, to the modifications of the resulting molecule, including the specifics related to SiPcs. The basic properties of Pcs and the degree of influence of different changes of the molecule on these properties are also described. The basic areas of use of Pcs are also mentioned. The experimental part...
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Preparation of fluorescent phthalocyanines for labeling of oligonucleotide probes IV.
Mikula, Daniel ; Miletín, Miroslav (advisor) ; Zitko, Jan (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department Department of Pharmaceutical Chemistry and Pharmaceutical Analysis Candidate Daniel Mikula Supervisor doc. PharmDr. Miroslav Miletín, Ph.D. Consultant Mgr. Michaela Kolářová Title of thesis Preparation of fluorescent phthalocyanines for labeling of oligonucleotide probes IV. Phthalocyanines (Pcs) are macrocyclic compounds with a conjugated system of double bonds. Thanks to this, they have interesting photophysical and photochemical properties that enable their practical use in pharmacy and medicine in the field of diagnostics or treatment of cancer diseases. This work deals with the preparation of axially disubstituted silicon complexes of phthalocyanines (SiPcs), which would have suitable properties for subsequent use in the labeling of oligonucleotide probes. The theoretical part is primarily devoted to the methods of Pcs preparation, from the choice of precursors, through the formation of the macrocycle and insertion of the central atom, to the modifications of the resulting molecule, including the specifics related to SiPcs. The basic properties of Pcs and the degree of influence of different changes of the molecule on these properties are also described. The basic areas of use of Pcs are also mentioned. The experimental part...
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STM study of adsorption and mobility of phtalocyanine molecules on passivated silicon surfaces at lower temperatures
Szabo, Michal ; Ošťádal, Ivan (advisor) ; Matvija, Peter (referee)
The thesis deals with an experiment for studying adsorption of phthalocyanin molecules on silicon surface passivated by a tin reconstruction. The main technique used for imaging surface is scanning tunneling microscopy (STM). The work contains a brief introduction to the studied problem. It deals with the STM method and STM construction. The used ultra-vacuum experimental system is characterized together with particular steps at sample preparation for STM measurements. During the sample preparation all necessary operations were tested on the newly modified system and calibration measurements of sample annealing and tin deposition were performed. A structure of the prepared surface Si(111) 7×7 was investigated by STM and conditions for the preparation in the new system were specified. STM images were used for an evaluation of results at optimizing preparation of the passivated surface. Obtained results are important for further experiments in frame of a research focused on growing molecular structures on silicon surfaces.
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Influence of Si surface passivation on growth and ordering of nanostructures
Matvija, Peter ; Kocán, Pavel (advisor) ; Rezek, Bohuslav (referee) ; de la Torre, Bruno (referee)
Silicon is currently the most widely used semiconductor material with applications ranging from solar cells and sensors to electronic devices. Surface functionalization of silicon with molecular monolayers can be used to tune properties of the material toward a desired application. However, site-specific adsorption of molecules or molecular patterning on silicon surfaces is a difficult task due to the high reactivity of silicon. In this work, we use scanning tunneling microscopy, ab-initio calculations and kinetic Monte Carlo simulations to study adsorption of organic molecules on a bare and thallium-passivated Si(111) surface. We show that the polarity of molecules has a large impact on bonding of the molecules with the bare surface. We demonstrate that, in comparison with the bare surface, molecules or single-atom adsorbates deposited on the Tl-passivated surface have significantly higher mobility. The increased mobility induces formation of 2D gases on the surface and enables formation of self-assembled molecular structures. We propose a novel method to directly visualize the 2D surface gases and we show that a phase of surface gases containing molecule-bound dipoles can be controlled by a non-homogeneous electric field. 1
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Preparation and photophysical evaluation of tetra-3,4-pyridoporphyrazines suitable for the photodynamic therapy
Čermák, Pavel ; Nováková, Veronika (advisor) ; Roh, Jaroslav (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department: Department of Biophysics and Physical Chemistry Candidate: Pavel Cermak Supervisor: Assoc. Prof. Veronika Novakova, PhD. Title of Thesis: Preparation and photophysical evaluation of tetra-3,4- pyridoporphyrazines suitable for the photodynamic therapy Tetra-3,4-pyridoporphyrazines (TPyPz) are aza-analogues of phthalocyanines. Their large system of conjugated bonds enables them to absorb light in the red part of the absorption spectrum. Due to their ability to produce singlet oxygen, they can be potentially used as photosensitizers in photodynamic therapy (PDT). Its mechanism is based on co-functioning of three elements - photosensitizer, light and oxygen. Photosensitizer excited by light absorption transfers its energy into tissue oxygen, thus, creating cytotoxic singlet oxygen. This method is beneficial for its high selectivity, low toxicity, minimal invasion and fast effect. The aim of this work was to synthetize and study water-soluble TPyPz suitable for PDT. Water solubility was achieved by quarternized amines, forming of salts or using suitable delivery systems (hydrophilic emulsion). Hydrophilicity was also increased by introduction of hydrophilic non-charged substituents (OH). At first, appropriate precursors for...
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Optimalization of methods for determination of singlet oxygen production and fluorescence emission of azaphthalocyanine derivatives
Hrubá, Lenka ; Nováková, Veronika (advisor) ; Kubíček, Vladimír (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department: Department of Biophysics and Physical Chemistry Candidate: Lenka Hrubá Supervisor: Assoc. Prof. Veronika Nováková, Ph.D. Title of Thesis: Optimization of methods for determination of singlet oxygen production and fluorescence emission of azaphthalocyanine derivatives Photodynamic therapy (PDT) with a singlet oxygen as an essential agent is believed to be an alternative way of cancer treatment or treatment of some cutaneous diseases. The principle of PDT is based on excitation of a photosensitizer by light absorption, followed by transfer of energy to tissue oxygen (3 O2) forming cytotoxic singlet oxygen (1 O2). The efficiency by which photosensitizer transforms absorbed energy to singlet oxygen is characterized by singlet oxygen quantum yields (ΦΔ). The aim of this thesis was to develop and optimize absolute method for determination of ΦΔ. In comparison to a relative method, no reference is needed in this case, which enables accurate results with lower error. Verification of the new method was performed in N,N- dimethylformamide with a zinc phthalocyanine as a model photosensitizer because of its well-known ΦΔ and with 1,3-diphenylisobenzofuran as a chemical quencher of 1 O2. Different sources of light for excitation...
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Excitation wavelength-dependent Raman spectra of single-layer graphene-phtalocyanine hybrid systems
Uhlířová, Tereza ; Vlčková, Blanka (advisor) ; Němec, Ivan (referee)
A systematic chemical and spectroscopic approach to evaluation of the effect of single-layer graphene (SLG) on Raman spectra of free-base phthalocyanine (H2Pc) in glass/SLG/H2Pc hybrid systems has been developed. By a combi- nation of electronic absorption spectra, Raman spectra at five excitation wave- lengths (532, 633, 647, 785 and 830 nm) and excitation profiles of H2Pc Raman spectral bands, the constitution of the three prepared hybrid sysems has been es- tablished in the following manner: Hybrid system I comprises probably a bilayer of H2Pc molecules, system VI approximately a monolayer of H2Pc, and system X a slightly reorganized monolayer of H2Pc molecules. Micro-Raman spectral map- ping of all three hybrid systems yielded H2Pc spectral bands (together with the SLG spectral bands) at all five excitation wavelengths. By contrast, for all three HOPG/H2Pc reference systems (HOPG = highly oriented pyrolytic graphite), prepared by the same procedure as the corresponding samples, H2Pc signal was detected only at 633 and 647 nm excitations. A selective increase of normalized Raman intensities of H2Pc spectral bands for the glass/SLG/H2Pc monolayer hybrid systems at 830 nm was revealed on the basis of a mutual comparison of Raman excitation profiles of all three samples of glass/SLG/H2Pc hybrid systems....
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