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Preparation and characterization of solar cells sensitized by bacteriochlorophyll a
Johanovská, Zuzana ; Pšenčík, Jakub (advisor) ; Dostál, Jakub (referee)
In this work, we explored the potential of bacteriochlorophyll a for its use in dye-sensitized solar cells. Bacteriochlorophyll a absorbs in the near-infrared spectral region where most of the pigments tested in dye-sensitized solar cells absorb poorly. It turned out that bacteriochlorophyll a rapidly oxidize to chlorophyl-like molecule at aerobic conditions, what is connected with an undesirable shift of the main absorption band to the shorter wavelengths. Therefore we prepared also several derivatives of bacteriochlorophyll a with similar absorption and tested their stability. We also studied a performance of solar cells with bacteriochlorophyll a and those derivatives, namely bacteriopurpurin, bacteriochlorophyllin and bacteriochlorin. It turned out that bacteriochlorin is the most stable of all the tested pigments. Moreover, it exhibits the best performance when used in the dye-sensitize solar cell.
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Conformational transitions and stability of quadruplex nucleic acids
Johanovská, Zuzana ; Mojzeš, Peter (advisor) ; Profant, Václav (referee)
The work deals with guanine quadruplexes, i.e., non-canonical four-stranded structures of nucleic acids rich in repetitive guanine sequences with potential biological and nanotechnological significance. The first part summarizes basic information about the structure and topology of quadruplexes, in the second part, the present knowledge about the quadruplexes in vivo are overviewed. The third part is devoted to experimental methods used in the present study, namely Raman spectroscopy, circular dichroism, and absorption spectroscopy. The next sections are devoted to the acquisition and treatment of your own experimental results. Five sequentially related oligonucleotides differing in the bases in a single-member loop were investigated. The effect of concentration of oligonucleotide and potassium ions K+ on the stability of these quadruplexes was investigated by Raman spectroscopy, and an unusually high thermal stability was observed. Other experiments included measurements of CDs and absorption spectra at lower oligonucleotide concentrations, two different potassium ion concentrations, and a comparison of the stability of individual modifications with the previously published results. Furthermore, the possible interaction with the cationic porphyrin CuTMPyP4, similar to the interaction with the antiparallel...
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Conformational transitions and stability of quadruplex nucleic acids
Johanovská, Zuzana ; Mojzeš, Peter (advisor) ; Profant, Václav (referee)
The work deals with guanine quadruplexes, i.e., non-canonical four-stranded structures of nucleic acids rich in repetitive guanine sequences with potential biological and nanotechnological significance. The first part summarizes basic information about the structure and topology of quadruplexes, in the second part, the present knowledge about the quadruplexes in vivo are overviewed. The third part is devoted to experimental methods used in the present study, namely Raman spectroscopy, circular dichroism, and absorption spectroscopy. The next sections are devoted to the acquisition and treatment of your own experimental results. Five sequentially related oligonucleotides differing in the bases in a single-member loop were investigated. The effect of concentration of oligonucleotide and potassium ions K+ on the stability of these quadruplexes was investigated by Raman spectroscopy, and an unusually high thermal stability was observed. Other experiments included measurements of CDs and absorption spectra at lower oligonucleotide concentrations, two different potassium ion concentrations, and a comparison of the stability of individual modifications with the previously published results. Furthermore, the possible interaction with the cationic porphyrin CuTMPyP4, similar to the interaction with the antiparallel...
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