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Endohedral fullerenes: From exotic chemical bonding to molecular electronics
Jaroš, Adam ; Straka, Michal (advisor) ; Uhlík, Filip (referee) ; Patzschke, Michael (referee)
This work focuses on the theoretical study of the physical and chemical properties of endohedral fullerenes, which can be used either to study exotic chemical bond- ing or as components in molecular electronics. Part of this work is focused on the study of interactions of simple molecules enclosed in a fullerene cage, such as H2O, HF, NH3, or their dimers, and the observation of the so-called charge-shift bonding. We have also investigated the bonding interactions between actinide atoms in fullerenes and described general trends associated with this bonding. In the course of studying actinide endohedral systems, we have proposed and cali- brated a methodological approach to investigate the actinide-actinide bonding, applicable in future research. The acquired knowledge about the interactions in endohedral fullerenes al- lowed us to design molecular components usable in so-called non-von Neumann architectures. First, we published a proof-of-concept study on diatomic MX molecules (M = hydrogen or metal, X = halogen or chalcogen) enclosed in a C70 cage. The molecule enclosed inside the cage can be rotated by an external electric field; thus the whole system acts as a switch. We found that the conductivity of the system depends on the rotational state of the molecule enclosed within the system, and the...
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Investigation of Single Molecule Charge Transport Properties and Geometrical Arrangement in Terpyridine Architectures Supported by the Tetraphenylmethane Tripod
Kolivoška, Viliam ; Sebechlebská, Táňa ; Šebera, Jakub ; Gasior, Jindřich ; Lindner, M. ; Lukášek, J. ; Valášek, M. ; Mayor, M. ; Mészáros, G. ; Hromadová, Magdaléna
Tripodal platforms were engineered recently to realize a well-defined directional contact between metallic electrodes and molecular architectures dedicated to serve as working elements for electronic applications. In this work we employ cyclic voltammetry, scanning tunneling microscopy break junction technique and theoretical approaches based on the combination of density functional theory and non-equilibrium Green´s function to investigate the geometrical arrangement and single molecule charge transport in terpyridine-based architectures supported by tetraphenylmethane tripod. We demonstrate that this architecture adopts a favorable geometrical arrangement capable of forming highly conductive molecular junctions and is thus suitable to serve as a basis for working molecular switches.
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Charge Transport through Molecular Towers Based on Tetraphenylmethane Tripods
Kolivoška, V. ; Šebera, Jakub ; Lindner, M. ; Valášek, M. ; Mayor, M. ; Mészáros, G. ; Gasior, J. ; Hromadová, M.
Molecular platforms with multiple anchors were introduced recently to provide robust coupling between molecular electronic components and metallic electrodes. In this work, charge transport in tower-shaped single molecule conductors based on tetraphenylmethane tripod possessing three thiol anchors is investigated by scanning tunneling microscopy break junction technique. The effect of tripod substitution pattern and number of repeating units in molecule is addressed. The substitution was found to influence conductance value in early stages of molecular junction evolution, where tower lays parallel to surface. In late stages, the charge is transported through principal molecular axis and junction breaks thermally in tilted configuration.
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Charge Transport through Molecular Towers Based on Tetraphenylmethane Tripods
Kolivoška, Viliam ; Šebera, Jakub ; Lindner, M. ; Valášek, M. ; Mayor, M. ; Mészáros, G. ; Gasior, Jindřich ; Hromadová, Magdaléna
Molecular platforms with multiple anchors were introduced recently to provide robust\ncoupling between molecular electronic components and metallic electrodes. In this work,\ncharge transport in tower-shaped single molecule conductors based on tetraphenylmethane\ntripod possessing three thiol anchors is investigated by scanning tunneling microscopy break\njunction technique. The effect of tripod substitution pattern and number of repeating units in\nmolecule is addressed. The substitution was found to influence conductance value in early\nstages of molecular junction evolution, where tower lays parallel to surface. In late stages, the\ncharge is transported through principal molecular axis and junction breaks thermally in tilted\nconfiguration.
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Funkční polymery s fotoelektrickou odezvou
Nešpůrek, Stanislav
Polymeric electronic devices have aroused increasing interest because of their potential low-cost applications, easy processing, possibility of modifications of their chemical structures and good compatibility with a variety of substrates. Many electrical and optical devices based on polymers can be mentioned: fuel cells, gas sensors, field-effect transistors, optical memories, information displays, hole/burning memories, lasers, etc.
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