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Preparation and study of a series of diketopyrrolopyrrole (DPP)-based polymers as photoactive substances
Solanský, Lukáš ; Richtár, Jan (referee) ; Cigánek, Martin (advisor)
The present diploma thesis deals with polymers based on organic pigments, their preparation, characterization and use as photoactive substances with a focus on artificial photosynthesis. The experimental part is devoted to the preparation of diketopyrrolopyrrole (DPP) based polymers. 7 DPP derivatives with 5 different side chains were prepared. The preparation of DPP polymers by Stille cross-coupling reaction and direct arylation were compared. Due to the higher efficiency and lower complexity of direct arylation, this polymerization method was used to prepare a series of 20 polymers consisting of a combination of 5 DPP derivatives and 4 comonomers. In the synthesis of several of the resulting polymers, the formation of an insoluble moiety was observed which could not be characterized by available methods, and even the subsequent application of such materials is not possible due to this. On the basis of the data obtained, it became apparent that in particular the bulky adamantane group and the comonomer tetrafluorobenzene were not suitable for the preparation of polymers, as they resulted in very limited soluble materials which, moreover, had a low degree of polymerization. In contrast, polymers containing butyl-TEG, octadecane, the comonomer thiophene and partially benzothiadiazole had degrees of polymerization in the range of 10-33 and exhibited excellent spectral and optoelectric properties. Tests of photocatalytic hydrogen evolution using DPP polymers are under development, but hydrogen was not demonstrably detected in initial measurements on selected polymer materials (P14 and P20).
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Artificial light-harvesting antenna based on an aggregation of bacteriochlorophyll c with selected pigments
Malina, Tomáš ; Pšenčík, Jakub (advisor) ; Litvín, Radek (referee)
Title: Artificial light-harvesting antenna based on an aggregation of bacteriochlorophyll c with selected pigments Author: Tomáš Malina Department: Department of Chemical Physics and Optics Supervisor of the master thesis: doc. RNDr. Jakub Pšenčík, Ph.D., KCHFO MFF UK Abstract: Solar energy is one of the most important energy sources for all living organisms. The light harvesting takes place in specialised photosynthetic complexes called antennas; they typically contain pigments held by a protein scaffold. Antennas of green bacteria, chlorosomes, are unique in this respect, for they do not need proteins to organise the pigments. The pigments contained in chlorosomes, bacteriochlorophyll (BChl) c, d or e, aggregate spontaneously. This self-aggregation can be used to form an artificial light-harvesting antenna the absorption spectrum of which can be extended by addition of other pigments. Antennas based on aggregation of BChl c with β-carotene and BChl a were prepared by a fast and slow method. The excitation energy transfer efficiency between these pigments was studied. The efficiency of energy transfer from BChl c to BChl a reached up to 95 %, the efficiency of energy transfer from β-carotene to BChl c was lower. An important role of β- carotene in artificial aggregates as well as in chlorosomes is its...
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