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Application of two-dimensional layers of transition metal dichalcogenides in plasmonics
Kocourková, Monika ; Hrtoň, Martin (referee) ; Kvapil, Michal (advisor)
Two-dimensional layers of transition metal dichalcogenides are materials with some very intriguing properties, such as the existence of room-temperature stable excitons in visible and near-IR spectrum. Their integration into plasmonic systems allows enhancement of their photoluminescence, absorption, etc., which can be used in various applications. This thesis begins with an overview of the basic terminology and fundametal principles behind these materials and hybrid systems. The theoretical part then focuses on some plasmon-excitonic system examples. Practical part of this thesis is aimed at simulating and optimizing two different plasmon-excitonic systems using monolayer molybdenum disulphide and tungsten disulphide.
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The D-A and pi-pi interactions and their use in self-assembly
Rejchrtová, Blanka ; Starý, Ivo (advisor) ; Kotora, Martin (referee)
The D-A and π-π Interactions and Their Use in Self-Assembly Due to their well-defined shape, size and properties gold nanoparticles represent an advantageous platform for the study of non-covalent interactions between ligands anchored to their surface both in solution and in monolayers or thin films. The aim of this thesis was the synthesis of ligands for gold nanoparticles bearing an anchoring group at one end and a planar π-electron rich pyrene unit at the other. Six structurally variable ligands were prepared differing in the pyrene substitution pattern and the spacer between the aromatic part and the acetylated thiol function. Furthermore, a synthetic pathway leading to extended π-electron systems (both electron rich and electron poor) such as hexabenzocoronene derivatives and its fragments was explored. The key steps in the synthesis of these compounds are the cyclization reactions of alkynes leading to polycyclic intermediates and their ensuing cyclodehydrogenation (Scholl reaction). All of the prepared ligands and their intermediates were characterized by spectroscopic methods. The structure of the key hexakis(pentafluorosulfanyl-phenyl)benzene was confirmed by single crystal X-ray crystallography. The prepared ligands bearing a pyrene unit were deacetylated and anchored to the surface of...
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Application of two-dimensional layers of transition metal dichalcogenides in plasmonics
Kocourková, Monika ; Hrtoň, Martin (referee) ; Kvapil, Michal (advisor)
Two-dimensional layers of transition metal dichalcogenides are materials with some very intriguing properties, such as the existence of room-temperature stable excitons in visible and near-IR spectrum. Their integration into plasmonic systems allows enhancement of their photoluminescence, absorption, etc., which can be used in various applications. This thesis begins with an overview of the basic terminology and fundametal principles behind these materials and hybrid systems. The theoretical part then focuses on some plasmon-excitonic system examples. Practical part of this thesis is aimed at simulating and optimizing two different plasmon-excitonic systems using monolayer molybdenum disulphide and tungsten disulphide.
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IMPOSING BIAXIAL STRAIN ON 2D LAYERED MATERIALS BY LIQUID-INDUCED SWELLING OF SUPPORTING POLYMER
Sampathkumar, Krishna ; Pekárek, J. ; Frank, Otakar
2D layered materials promise to revolutionize the field of electronics, photonics, optoelectronics, energy storage, and sensing, etc. 2D materials have exceptional mechanical properties, with critical elongation >10%. Employing the strain to manipulate the electronic structure of these 2D materials could lead to further improvement of their implementation in many aspects. The ease of manipulation of their electronic structure can be one of the critical factors for their utilization in photonic devices. Apart from the strain, which decreases (increases) the bandgap energy at the rate of similar to 100 meV under 1% of biaxial tension (compression), also the layer number causes bandgap energy change of, e.g., 0.5 eV between bulk (1.3 eV) and monolayer MoS2 (1.8 eV). In our work, we focus on using the swelling behavior of PMMA/SU8 polymer in methanol to impose the strain on 2D layered materials. In the first trials, we have shown that it is possible to reach a strain gradient from 0 to similar to 0.5% of biaxial strain via simple swelling of polymer substrates, both for graphene [1] and transition metal di-chalcogenides (TMDC) like MoS2. Raman spectroscopy was used to probe the lattice strain in the materials through measuring changes of vibrational frequencies, and photoluminescence was used to probe the strain-induced bandgap character and energy in TMDC at room temperature. The surface corrugation of the 2D material after the soaking was recorded with the help of atomic force microscope (AFM).
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Towards lateral interactions within self-organized monomolecular layers
Staněk, Jan ; Baše, Tomáš (advisor) ; Bastl, Zdeněk (referee)
This work aimed at the utilization of chemical principles for stabilization of self-assembled monolayers (SAMs) of carboranethiol derivatives on a flat gold surface. Ideas employing surface confined coordination complex formation and dipole-dipole intermolecular interactions were outlined and the respective literature survey was compiled. Preliminary experiments were carried out to test for their feasibility and surfaces modified with self assembled monolayers proved very sensitive to reaction conditions ordinarily used for bulk synthesis. The chemical sensitivity of the studied surfaces, the necessity of using appropriate surface-sensitive analytical techniques and the depth of the problem initially defined made this task both advanced and challenging. The formation of intermolecular coordination complexes with ω-carboxylated SAMs of meta-carborane-9-thiol was chosen to answer those issues, extending the previous work of the author on carboxylated carboranethiol isomers presented in his bachelor thesis. Concepts different of those based on coordination chemistry are briefly discussed as well, but more as prospects for future work and to present this work in a broader context to which it belongs. Characterization of molecules assembled on a surface in a single layer requires surface sensitive...
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The D-A and pi-pi interactions and their use in self-assembly
Rejchrtová, Blanka ; Starý, Ivo (advisor) ; Kotora, Martin (referee)
The D-A and π-π Interactions and Their Use in Self-Assembly Due to their well-defined shape, size and properties gold nanoparticles represent an advantageous platform for the study of non-covalent interactions between ligands anchored to their surface both in solution and in monolayers or thin films. The aim of this thesis was the synthesis of ligands for gold nanoparticles bearing an anchoring group at one end and a planar π-electron rich pyrene unit at the other. Six structurally variable ligands were prepared differing in the pyrene substitution pattern and the spacer between the aromatic part and the acetylated thiol function. Furthermore, a synthetic pathway leading to extended π-electron systems (both electron rich and electron poor) such as hexabenzocoronene derivatives and its fragments was explored. The key steps in the synthesis of these compounds are the cyclization reactions of alkynes leading to polycyclic intermediates and their ensuing cyclodehydrogenation (Scholl reaction). All of the prepared ligands and their intermediates were characterized by spectroscopic methods. The structure of the key hexakis(pentafluorosulfanyl-phenyl)benzene was confirmed by single crystal X-ray crystallography. The prepared ligands bearing a pyrene unit were deacetylated and anchored to the surface of...
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(Strept)avidin-biotin interactions at amalgam electrodes covered by thiol monolayer
Josypčuk, Bohdan ; Mareček, Vladimír ; Yosypchuk, O.
Carboxylic group of 11-mercaptoundecanoic acid (MUA) can be used to creat a peptide bond with species containing amino group, e.g., peptides, and proteins. By the help of EDC-NHS technology, streptavidin or avidin was covalently bonded with MUA-monolayer at a silver solid amalgam electrode. Such prepared electrode was used for detecting biotin and biotinylated albumin in the supporting electrolyte (0.15 M NaCl, 0.05 M TRIS, pH 7.0). Electrochemical impendance spectroscopy was performed for the biosensor response monitored by impedance spectroscopy. Binding of biotin or biotinylated albumin with (strept)avidin a change in the resistance of the sensor in the concentration range of 0.5-20 μg mL-1. Electrochemical regeneration of the amalgam electrode permits simply to renew its surface and to create the new biosensor.
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Monolayers at electrodes as basis for models of natural membranes
Josypčuk, Bohdan ; Mareček, Vladimír
Properties of thiol (HS(CH2)10COOH) monolayers were investigated at stationary electrodes based on silver, copper, bismuth and cadmium solid amalgams covered by a mercury meniscus or by a mercury film. For comparison, parallel experiments were performed at a classical hanging mercury drop electrode. Dependences of monolayer parameters on time of electrochemical deposition of thiol and on scan rate were performed. Statistical evaluation of all obtained results has confirmed that solid amalgam electrodes are a convenient tool for research of thiol layers.
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