Národní úložiště šedé literatury Nalezeno 7 záznamů.  Hledání trvalo 0.01 vteřin. 
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.
Single Molecule Conductance and Junction Formation in Solution. Solvent Effect
Lachmanová, Štěpánka ; Šebera, Jakub ; Gasior, Jindřich ; Dupeyre, G. ; Lainé, P. P. ; Mészáros, G. ; Hromadová, Magdaléna
The single molecule conductance of expanded pyridinium derivative terminated by pyridyl\nnitrogen as an anchoring group at both ends of the molecule in two different environments\nwas measured by scanning tunneling microscopy break junction technique (STM-BJ). The\nvalues obtained in commonly used 1,3,5-trimethylbenzene (TMB) significantly differ from\nthe values acquired in a mixture of TMB and ethanol. Markedly lower junction length and\nhigher conductance indicate strong influence of adsorption of the molecule to the substrate\nsurface in pure TMB compared to the TMB and ethanol mixture.
Oxidation of Bioflavonoids in Respect to their Chemical Structure
Sokolová, Romana ; Ramešová, Šárka ; Kocábová, Jana ; Degano, I.
The electrochemical oxidation of flavone luteolin, flavanone taxifolin and flavonols derived from quercetin was studied by cyclic voltammetry. Only small differences in the chemical structure of bioflavonoids resulted in extremely variable oxidation pathways and products. Products of oxidation and further decomposition were determined by HPLC-ESI-MS/MS and HPLC-DAD.
Závislost vodivosti pyridiniových molekul na jejich struktuře
Lachmanová, Štěpánka ; Hromadová, Magdaléna ; Kolivoška, Viliam ; Pospíšil, Lubomír ; Gasior, Jindřich ; Mészáros, G. ; Lainé, P. P.
Vývojáři elektronických součástek stojí před palčivým problémem. Podle Moorova zákona 1, empirického pravidla odhadujícího možnosti v miniaturizaci elektronických součástek, již brzy nebude možné pokračovat ve zvyšování výkonu elektronických zařízení při zachování jejich rozměrů. Současná věda navrhuje hned několik možných směrů, jak nahradit doposud sloužící technologie na bázi křemíku. Jednou z nich je vývoj a použití specializovaných molekul 2.
Charge Transport in Single Molecule Junctions of Spirobifluorene Scaffold
Hromadová, Magdaléna ; Kolivoška, Viliam ; Sokolová, Romana ; Šebera, Jakub ; Mészáros, G. ; Valášek, M. ; Mayor, C.
Single molecule conductance of two spirobifluorene molecules of different length have been studied by scanning tunneling break junction (STM–BJ) methodology. First molecule contains a tripodal spirobifluorene platform, whereas a second one contains the same platform with chemically attached p-phenyleneethynylene molecular wire. The conductance values change only slightly between these two molecules, which demonstrated that such a platform provides both highly conducting pathway and stable anchor for the future molecular electronic devices.
Comparison of Techniques for Single-Molecule Conductance Measurements of Expanded Pyridinium Molecules
Lachmanová, Štěpánka ; Hromadová, Magdaléna ; Sokolová, Romana ; Kocábová, Jana ; Gasior, Jindřich ; Mészáros, G. ; Lainé, P. P.
This work is focused on the comparison of two techniques of single-molecule conductance measurements: Scanning Tunneling Microscopy Break Junction technique and Mechanically Controlled Break Junction technique. The structure of studied compound 9-(pyridin-4-yl)benzo[c]benzo[1,2]quinolizino[3,4,5,6-ija][1,6]naphthyridin-15-ium allows the formation of the molecular bridge between two gold electrodes, which are connected to a source of the constant voltage in both of the used methods. The differences, advantages and disadvantages of both of the techniques will be discussed. Both techniques provided two values of conductance of studied compound depending on the experimantal conditions.
Spectroelectrochemical Study of Electron Transfer in the Extended 1,1 '-Bipyridinium Cation
Hromadová, Magdaléna ; Kolivoška, Viliam ; Pospíšil, Lubomír ; Valášek, M. ; Tarábek, Ján
Electron transfer (ET) in the extended 1, 1 ' -bipyridinium has been investigated by UV Nis/NIR and EPR in-situ spectroelectrochemical techniques. During the in-situ cyclic voltammetric scan no EPR signal was observed at the potential corresponding to the first electron transfer at room temperature, whereas the EPR signal for the subsequent ET steadily increased and was observed even at the potentials corresponding to the fourth electron transfer. The EPR signal was detected for the first electron transfer step only at elevated temperature. The evidence for the presence of comproportionation processes and for the formation of n-dimer is discussed.

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