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Electric and dielectric properties of organic materials for photovoltaic applications
Florián, Pavel ; Nešpůrek, Stanislav (referee) ; Zmeškal, Oldřich (advisor)
Diploma thesis deals with the use of organic materials in photovoltaic applications and the study of their electric and dielectric properties. The theoretical part of thesis deals issue of the use of organic polymeric materials in photovoltaics and their advantages and disadvantages. Next are the results of various studies of organic solar cells by other authors. In the practical part of the work are shown experimental results (volt-ampere characteristics and impedance spectra) of samples of organic semiconductors and their evaluation.
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Deposition and study of optoelectronic properties of thin films for organic photonics
Nagyová, Veronika ; Hubálek, Jaromír (referee) ; Weiter, Martin (advisor)
This diploma thesis concentrates on the properties characterization of new organic materials for solar cells. In the theoretical part, there is a solar cells themed literature search, there is described a mechanism of conversion of solar energy, factors influencing photovoltaic conversion efficiency and materials using for preparation of organic solar cells. The practical part includes the preparation of solar cells and characterization of optical and electrical properties of the studied materials in thin layers and solutions. Used materials were conjugated polymers and derivatives of fullerenes.
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Organic solar cells based on polymers
Nagyová, Veronika ; David, Jan (referee) ; Weiter, Martin (advisor)
This bachelor thesis concentrates on the properties characterization of new organic materials for solar cells. In the theoretical part, there is a solar cells themed literature search, there is described a mechanism of conversion of solar energy and the structure of organic solar cells. The practical part includes the preparation of solar cells and characterization of basic optical and electrical properties of the studied materials.
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Conjugated porous polymers derived from diethynylarenes by chain-growth polymerization and polycyclotrimerization
Slováková, Eva ; Sedláček, Jan (advisor) ; Merna, Jan (referee) ; Červený, Libor (referee)
4 ABSTRACT The synthesis has been described yielding a new type of rigid conjugated polymer networks which possess a high content of permanent micropores and macropores and exhibit high surface areas up to 1469 m2/g. The networks have been prepared via chain-growth coordination polymerization catalysed with insertion catalysts based on Rh complexes. This polymerization has been newly applied to bifunctional acetylenic monomers of diethynylarene type (1,4-diethynylbenzene, 1,3-diethynylbenzene and 4,4'-diethynylbiphenyl). The covalent structure of the networks consists of the polyacetylene main chains densely connected by arylene struts. The W and Mo metathesis catalysts have been revealed as inefficient for the synthesis of these networks. The increase in the polymerization temperature and time has been shown to affect positively the content and the diameter (up to 22 nm) of the mesopores in the networks. A mechanism has been proposed that explains the mesopores formation as a result of mutual knitting of small particles of the microporous polymer. The application of emulsion polymerization technique allowed to prepare texturally hierarchical polyacetylene networks possessing interconnected open macropores (diameter up to 4,8 μm) the walls of which exhibited micro/mesoporous texture. It was demonstrated...
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Novel conjugated polymers of the metallo-supramolecular and polyelectrolyte class
Hladysh, Sviatoslav ; Vohlídal, Jiří (advisor) ; Strachota, Adam (referee) ; Jindřich, Jindřich (referee)
This thesis targets the development of conjugated polymers with improved process ability from solutions. Two types of ionic polymers are addressed: (i) conjugated metallo-supramolecular polymers (MSPs) composed of conjugated heteroaromatic unimers (building blocks) linked to chains by various metal ions giving charged main chains, and (ii) polythiophene polyelectrolytes containing ionic pendants. Processing advantages of conjugated polyelectrolytes consist in the possibility of their processing from solutions in green solvents such as alcohols or even water. The advantages of MSPs consist in the thermodynamic control of the degree of polymerization (length) of their chains in solutions by the choice of solvent and temperature. As a result, MSPs reversibly provide systems of low viscosity that can be processed from solutions more easily than high-molar-mass polymers giving highly viscous solutions. Synthesis of appropriately designed unimer(s) is the key step of preparation of an MSP. Within this thesis, a series of novel unimers composed of linear oligothiophene type (mono-, bi-, ter- a thieno-thiophene- diyl) central blocks capped with 2,6-bis(oxazoline-2-yl)pyridine (pybox) or 2,6-bis(imidazole-2-...
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synthesis of conjugated polyacetylene based polymers
Duchoslavová, Zuzana ; Zedník, Jiří (advisor) ; Doubský, Jan (referee)
Mostly new acetylene based monomers were prepared. All monomers were prepared by the means of standard spectroscopic methods. All monomers were successfully polymerized using standard metathesis TaCl5 based catalyst. Prepared polymers were characterized by the means of GPC/GPC-MALLS chromatography and standard spectral methods. Fluorescence properties of all prepared compounds were also studied: quantum fluorescence yields were determined and excitation and emission fluorescence spectra were recorded. Polymerization on modern metathesis Grubbs-Hoveyda catalytic systems of all prepared monomers was also tested. These reactions were only partially successful and only low molecular weight oligomers in mediocre yields were obtained.
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Functionalized microporous polymer networks prepared from ethynylarenes
Stahlová, Sabina ; Sedláček, Jan (advisor) ; Etrych, Tomáš (referee) ; Červený, Libor (referee)
The preparation of a new group of functionalized conjugated polymer networks has been described based on spontaneous quaternization polymerization of ethynylpyridines with bis(bromomethyl)arenes. The networks consisted of polyacetylene chains with pyridyl and pyridiniumyl pendants cross-linked with -CH2(arylene)CH2- links. The variation of the ratio of monomer and quaternization agent in the feed modified the ratio of pyridyl and pyridiniumyl groups in the networks (pyridyl/pyridiniumyl ratios from 0 to 1.32). The networks did not exhibit a permanent microporosity that could be confirmed by nitrogen adsorption at 77 K. Nevertheless, all networks were active in capture of CO2 at 293 K (up to 0.73 mmol CO2/g, 750 Torr). It has been hypothesized that CO2 capture reflected formation of a temporary porous texture of the networks through conformational changes of the network segments enabled by the segments mobility at room temperature. The preparation of functionalized conjugated polymer networks with permanent micro/mesoporosity (SBET up to 667 m2 /g) has been described that was based on chain coordination copolymerization of acetylenic monomers. The copolymerization of 1,4-diethynylbenzene or 4,4'-diethynylbiphenyl with mono or diethynylbenzenes bearing NO2 or CH2OH groups has been demonstrated as...
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Preparation of functionalized polyacetylenes with linear and cross-linked architecture
Havelková, Lucie ; Sedláček, Jan (advisor) ; Balcar, Hynek (referee)
The phenylacetylene type monomers with benzene ring substituted with one or two aldehyde groups (besides an ethynyl group) were efficiently polymerized into linear mostly high-molecular-weight polyacetylenes with aldehyde groups in pendants if the complex [Rh(NBD)acac] was used as the polymerization catalyst. To achieve high yield and molecular weight of the polymer the positioning of the aldehyde group to meta position with respect to the ethynyl group was most appropriate. It was confirmed that polyacetylenes with aldehyde groups were modifiable by a reaction with p-toluidine under formation of Schiff base type pendant groups. 1,3-Diethynylbenzenes with various substituents in position 5 on the ring (R = H, F, Cl, Br, HCO, NO2, COOCH3) were efficiently polymerized with [Rh(NBD)acac] catalyst into microporous or micro/mesoporous polyacetylene networks that exhibited specific surface area from 311 to 1146 m2 /g. In the case of the networks with HC=O groups, the positive effect of these groups was confirmed on the capacity of the network in CO2 and methanol vapor capture. The composition and texture of the networks possessing HC=O groups were partly reversibly modifiable in reaction with p-toluidine.
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Characterization of poly(1,4-diethynylbenzene) by IGC method
Petrášová, Sabina ; Sedláček, Jan (advisor) ; Pacáková, Věra (referee)
Poly(1,4-diethynylbenzene) ( -conjugated polymer) was prepared as an insoluble polymer network via chain coordination polymerization of 1,4-diethynylbezene catalyzed with [Rh(NBD)acac] complex. Thermodynamic properties and acid-base characteristics of the prepared poly(1,4-diethynylbenzene) were studied by means of Inverse Gas Chromatography (IGC) in the temperature range 80-100 řC. Retention data of selected testing substances were used to determine the Gibbs energy of sorption, the sorption enthalpy and their acid-base and disperse parts as well as the disperse contribution to the surface energy and parameters of KA, KD, ANHPS and DNHPS quantifying the acid-base character of the studied polymer. The results showed that poly(1,4-diethynylbenzene) interacted more efficiently with Lewis bases than with Lewis acids. The values of experimental sorption enthalpy were used for the determination of the parameters KA and KD. Values of these parameters classify poly(1,4-diethynylbenzene) as the material with a slightly acid character. This conclusion is further supported by the results of H. P. Schreiber method based on the application of ANHPS and DNHPS parameters for the evaluation of the acid-base properties of the material. The infrared spectroscopy proved that poly(1,4-diethynylbenzene) contained...
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