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Materials with FR/NIR photoluminiscence
Chovanec, Filip ; Kratochvíl, Matouš (referee) ; Vala, Martin (advisor)
This bachelor thesis is focused on issues of materials, whose fluorescence maximum is located in regions of the far-red (FR), which is in range from 700-800 nm or near-infrared (NIR), from 800-2500 nm, electromagnetic radiation. Materials, which this thesis is focused on, are organic molecules with charge transfer (CT) system. They are based on electron-donor and electron-acceptor groups located on the opposite sides of the same molecule. Diphenylamine behaves as electron-donor. This moiety is connected to different batch of atoms, which figure as electron-acceptor group. Connection is formed by -conjugated bridge of diphenyl stilbene or dixylil stilbene. Such a variable system has an optionally adjustable magnitude of charge transfer phenomenon, and it is reflected in the fluorescence maximum. Knowledge about fluorescence of these molecules, phenomena accompanying and outrunning this radiation, was acquired through the theoretical research. Strategies, how to set such a DA system or how to set up molecules with FR/NIR fluorescence were also obtained. Practically, characterization and dependence of fluorescence maximum on structure of these molecules, as well as dependence on solvent were determined by fluorescence spectroscopy. Photoluminescence quantum yield was calculated from emission and excitation spectra and studied how structural changes changed values of this quantum yield and fluorescence lifetime too. The result of the bachelor thesis was the finding, that the stronger the charge transfer phenomenon occurs in the molecule, the greater bathochromic shift of emission spectra was observed. At the same time, it was discovered that it was the case of liquid sample, solid samples had shown smaller bathochromic shift.
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Materials with FR/NIR photoluminiscence
Chovanec, Filip ; Kratochvíl, Matouš (referee) ; Vala, Martin (advisor)
This bachelor thesis is focused on issues of materials, whose fluorescence maximum is located in regions of the far-red (FR), which is in range from 700-800 nm or near-infrared (NIR), from 800-2500 nm, electromagnetic radiation. Materials, which this thesis is focused on, are organic molecules with charge transfer (CT) system. They are based on electron-donor and electron-acceptor groups located on the opposite sides of the same molecule. Diphenylamine behaves as electron-donor. This moiety is connected to different batch of atoms, which figure as electron-acceptor group. Connection is formed by -conjugated bridge of diphenyl stilbene or dixylil stilbene. Such a variable system has an optionally adjustable magnitude of charge transfer phenomenon, and it is reflected in the fluorescence maximum. Knowledge about fluorescence of these molecules, phenomena accompanying and outrunning this radiation, was acquired through the theoretical research. Strategies, how to set such a DA system or how to set up molecules with FR/NIR fluorescence were also obtained. Practically, characterization and dependence of fluorescence maximum on structure of these molecules, as well as dependence on solvent were determined by fluorescence spectroscopy. Photoluminescence quantum yield was calculated from emission and excitation spectra and studied how structural changes changed values of this quantum yield and fluorescence lifetime too. The result of the bachelor thesis was the finding, that the stronger the charge transfer phenomenon occurs in the molecule, the greater bathochromic shift of emission spectra was observed. At the same time, it was discovered that it was the case of liquid sample, solid samples had shown smaller bathochromic shift.
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