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Synthesis and Study of Nano-Structured Perovskites for Applications in Organic Electronics
Jančík Procházková, Anna ; Kuřitka, Ivo (oponent) ; Částková, Klára (oponent) ; Krajčovič, Jozef (vedoucí práce)
Diversity and unique properties, such as exceptionally high photoluminescence quantum yields (PLQYs), predetermine metal halide perovskite nanoparticles (PNP) to be applied in optoelectronic and photonic devices. In this work, nature-inspired capping agents were employed not only for the PNP stabilization but also for modifying their surface to broaden the functionality of the resulting material. In the very beginning, a ligand-assisted precipitation technique was optimized for the preparation of the PNP. Here, adamantane-1-amine (AdNH2) alongside hexanoic acid (HeA) were chosen as capping agents for nanoparticles stabilization and passivation. It was demonstrated that the choice of the solvent system and the precipitation temperature have a crucial effect on the resulting optical properties of the colloidal solutions. Simultaneously, the influence of concentration of precursor chemicals on the resulting morphology and optical properties was investigated. Also, different carboxylic acids were tested as capping agents among AdNH2 and the colloidal stability of the resulting colloidal solutions was evaluated. To demonstrate the diversity of the ligand-assisted precipitation technique of PNP preparation, L-lysine and L-arginine were employed initially for the surface passivation. As a result, colloidal solutions with emission within a narrow bandwidth of the visible spectrum and remarkable photoluminescence quantum yield (PLQY) close to 100% were obtained. Blocking -amino group of L-lysine by tert-butoxycarbonyl group suggested preferential binding of the side chain of L-lysine to the perovskite core. Furthermore, defined amounts of water were added into the precursor solutions which caused shifts of emission spectra due to quantum confinement effects. Water molecules were assumed to form highly mobile species leading to the enhancement of controlling the perovskite lattice growth. Merging perovskite nanomaterials with peptides are expected to pave a way to the new class of materials possessing exceptional optoelectronic properties alongside self-assembly and sensing abilities. As a proof-of-concept, a cyclic(RGDFK) pentapeptide was used for PNP stabilization. However, peptides are known for their sensitivity to their environment. Therefore, peptide nucleic acid (PNA) was used for PNP stabilization as a robust artificial analogue for deoxyribonucleic acid (DNA). Here, optical properties of thymine-based PNA monomer and trimer stabilized PNP were studied. Additionally, the sensing ability of the PNA ligand for adenine moiety was demonstrated by photoluminescence quenching via charge transfer. We envision that combining the unique tailored structure of PNA and the prospective optical features of PNP could expand the applications especially in the field of optical sensing devices.
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Nature-inspired macro cyclic systems for bioorganic applications
Prekopová, Terézia ; Cigánek, Martin (oponent) ; Krajčovič, Jozef (vedoucí práce)
The bachelor thesis deals with nature-inspired macrocyclic compounds and their possible use in organic bioelectronics. The theoretical part of this bachelor thesis introduces semiconductor materials in organic bioelectronics and provides a general overview of selected classes of macrocyclic compounds currently occurring. It includes their history, properties, reactivity and use in various industries. An important point of this part are cyclodextrins, which are characterized by their high biocompatibility and affinity for a wide range of guests depending on the structure of the cyclodextrin. They are capable of molecular recognition to form inclusion complexes with guest particles. The work also deals with chemical modifications of cyclodextrins in order to improve selected physicochemical properties and practical applications of cyclodextrins. The experimental part consists of the synthesis, purification and characterization of key macrocyclic -cyclodextrin derivatives selectively modified at position 6 of one glucopyranose unit for the synthesis and study of advanced supramolecular structures for potential applications in organic bioelectronics.
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The synthesis of organic -conjugated systems for advanced photonic applications
Prekopová, Terézia ; Richtár, Jan (oponent) ; Krajčovič, Jozef (vedoucí práce)
This diploma thesis is focused on the synthesis of new, organic, -conjugated systems with potential use in the field of singlet fission (SF). It is one of the most efficient multiexciton generation processes studied so far, which offers the potential to increase the efficiency of solar cells. The theoretical part focuses on the description of SF and the molecules providing this phenomenon. The first aim of the experimental part is focused on the synthesis of target pentacene and anthracene derivatives. The work presents and verifies three synthetic approaches to the preparation of these molecules, of which only one has proven to be successful. The second aim deals with the synthesis of intermediates that are crucial for the preparation of target pyrene fused pyrazaacenes. The synthesis consists of the oxidation of pyrene and the condensation of 4,5-diketone or 4,5,9,10-tetraketone with commercially available diamines or diamines prepared by us. A basic optical characterization was performed on these derivatives, which showed the effect of substitution on excimer emission. Assuming the same quantum fluorescence yield for all molecules and comparing the spectral measurements, it was found that the solid phase excimer emission is significantly higher than in solution.
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Bio-inspirované organické materiály pro fotodynamickou terapii
Švarcová, Nikola ; Cigánek, Martin (oponent) ; Krajčovič, Jozef (vedoucí práce)
Fotodynamická terapie je léčebná metoda využívající klinickou aplikaci fotosensitizérů pro alternativní léčbu onkologických a zánětlivých onemocnění. Jedním z důležitých elementů pro efektivní průběh terapie je použití fotosensitizérů, látek vykazujících absorpční vlastnosti. Díky konjugovanému systému mohou flaviny absorbovat světlo a sloužit tak jako potenciální fotosensitizéry. Předložená bakalářská práce se zabývá přípravou nového flavinového derivátu, inspirovaného riboflavinem. Strukturní izomery riboflavinu, alloxaziny, poskytují snadnou syntetickou modifikovatelnost pro vylepšení materiálových vlastností. V teoretické části je popsán princip a mechanismus fotodynamické terapie, moderní trendy jejího použití v medicínských aplikacích, limitace, výhody a nepostradatelné elementy pro efektivní průběh terapie. V práci je následně představena možnost potenciálního využití flavinů jako přírodou-inspirovaných fotosensitizérů absorbujících světlo v infračervené oblasti spektra. Experimentální část popisuje přípravu meziproduktů a finálních prekurzorů, 1,3-dialkylovaného uracilu a 1,2-diketonu odvozeného ze struktury acenaftenu. Ověřené syntetické cesty poskytovaly v práci vysoké výtěžky připravených meziproduktů a finálních prekurzorů, což bude přínosné pro následné syntetické studie, a naleznou tak uplatnění pro další přípravu série nových flavinových derivátů.
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Implementation of polycyclic saturated systems in synthesis of advanced organic and hybrid materials for application in organic electronics
Jančík, Ján ; Částková, Klára (oponent) ; Todorov, Petar (oponent) ; Krajčovič, Jozef (vedoucí práce)
Advanced materials in all areas of industry have experienced an extreme boom in recent years due to the constant miniaturization of components and electronics, the creation of smart and functional materials, the development of new therapeutic and diagnostic methods, and finally, the improvement and streamlining of production processes. An important position in this system is in the sector of organic electronics, in which many technological companies and investors see a great future. To prove the flexibility, versatility, and scalability of the advanced materials, completely new adamantyl-substituted polythiophenes were prepared and investigated. As a strong competitors to commercially used materials, the novel polymers show that the field of organic electronics has not reached its borders until now. The wide characterisation and study of the new polymers was provided. To extend the research area, a series of completely new photoswitching molecules based on para-bis(2-thienyl)phenylene were designed, prepared, and investigated as another type of advanced organic materials. Following the actual trends, even perovskite materials were investigated. A completely new, environmentally friendly, low cost, and ease-of-use scalable method was invented and optimized for four mostly used hybrid lead-halide perovskites macro crystals preparation. This method could be the answer for the industrial production of high-quality, defect-free, and symmetrical perovskite macrocrystals. On the other hand, different kinds of perovskite nanoparticles were investigated to improve stability and properties. The basic ligand stabilisation was examined, focusing on adamantyl-based ligands and for improving properties, the stabilisation by polymeric matrix was designed. Adamantyl substituted polythiophenes were used as conductive matrix for perovskite nanoparticles in the form of thin layer stabilisation.
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The synthesis of organic -conjugated systems for advanced photonic applications
Prekopová, Terézia ; Richtár, Jan (oponent) ; Krajčovič, Jozef (vedoucí práce)
This diploma thesis is focused on the synthesis of new, organic, -conjugated systems with potential use in the field of singlet fission (SF). It is one of the most efficient multiexciton generation processes studied so far, which offers the potential to increase the efficiency of solar cells. The theoretical part focuses on the description of SF and the molecules providing this phenomenon. The first aim of the experimental part is focused on the synthesis of target pentacene and anthracene derivatives. The work presents and verifies three synthetic approaches to the preparation of these molecules, of which only one has proven to be successful. The second aim deals with the synthesis of intermediates that are crucial for the preparation of target pyrene fused pyrazaacenes. The synthesis consists of the oxidation of pyrene and the condensation of 4,5-diketone or 4,5,9,10-tetraketone with commercially available diamines or diamines prepared by us. A basic optical characterization was performed on these derivatives, which showed the effect of substitution on excimer emission. Assuming the same quantum fluorescence yield for all molecules and comparing the spectral measurements, it was found that the solid phase excimer emission is significantly higher than in solution.
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Vývoj katalyzátoru pro epoxidaci methylesterů
Pham, Tien Thanh ; Krajčovič, Jozef (oponent) ; Kučerík, Jiří (vedoucí práce)
Diplomová práce je zaměřená na studium heterogenních katalyzátorů v epoxidaci methylesteru řepkového oleje. Epoxidy těchto komponent mají uplatnění v řezných olejích, kde by mohly nahradit dosud využívající oleje z fosilních zdrojů. Epoxidace je katalyzovanou reakcí pomocí homogenních katalyzátorů na bázi minerálních kyselin. Ty však mají korozivní vlastnosti a špatně se separují po reakci. Tato práce je však zaměřená na studium heterogenních katalyzátorů. Produkty reakce byly analyzovány pomocí GC, SIMDIS a ATR-FTIR. Pro určení složení, strukturních, texturních a redukčních vlastností katalyzátorů byly využity pokročilé analytické metody jako ICP-OES, XRF, XRD, SEM, rtuťová porozimetrie a TPR H2.
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Charakterizace kovů v atmosférickém aerosolu
Cigánková, Hana ; Ličbinský, Roman (oponent) ; Vojtíšek,, Michal (oponent) ; Krajčovič, Jozef (vedoucí práce)
Předložená disertační práce se zabývá charakterizací prvků ve dvou velikostních frakcích městského aerosolu, který byl vzorkován ve všech ročních obdobích na venkovní terase Ústavu analytické chemie AV ČR v Brně v roce 2018. V teoretické části práce jsou shrnuty základní informace o analýze a zdravotních rizicích atmosférického aerosolu a na něm vázaných kovech. Dále jsou v práci popsány metody stanovení inhalační biodostupnosti částic aerosolu a metody používané pro stanovení oxidativního potenciálu. V první části práce je podrobně popsáno vzorkování a analýza částic městského aerosolu. Byla stanovena hmotnostní koncentrace obou velikostních frakcí částic aerosolu a celková koncentrace 21 prvků vázaných na částice. Pomocí obohacovacího faktoru a pozitivní maticové faktorizace byly vypočítány pravděpodobné zdroje analyzovaných prvků. Druhá část práce se zabývá stanovením oxidativního potenciálu aerosolu a biodostupné koncentrace analyzovaných prvků ve třech simulovaných plicních tekutinách (deionizovaná voda, simulovaná kapalina plicních sklípků a Gamblův roztok). Kromě stanovení oxidativního potenciálu reálných vzorků byly stanoveny i oxidativní potenciály jednotlivých prvků. Ze získaných výsledků byl vypočítán pravděpodobný příspěvek prvků ke změřenému oxidativnímu potenciálu.
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Synthesis of soluble nature-inspired N, N-alkylated riboflavin derivatives, study of the effect of alkyl groups
Ivanová, Lucia ; Maier,, Lukáš (oponent) ; Krajčovič, Jozef (vedoucí práce)
By flavin's unique structure, nature predestined riboflavin and its derivatives to the participation in redox processes within the bodies of all the living organisms. These biomolecules draw attention with intriguing optical properties and photosensitising abilities. Nature-inspired flavin derivatives share these qualities, and there is also a possibility of fine-tuning for the particular application from the chemical point of view. The thesis deals with two main aims. The first aim handles the synthesis of the trimer heteroaromatic precursor and 1,2-diketone. These key intermediates are essential for the future synthesis of the central aromatic core of the novel NH-free non-fused flavin derivative. The thesis introduces and verifies three approaches, including oxidation of diarylalkynes, nucleophilic addition of a corresponding organolithium compound to a Weinreb amide and benzoin condensation. The second aim covers the properties customization of NH-free fused systems by implementation of linear and bulky alkyl side-chains on the nitrogen atoms N1 and N3 of the alloxazine dilactam. N,N-alkylation introduced an increase in solubility in common organic solvents dichloromethane and chloroform. For the derivatives with 2-(adamantan-1-yl)ethyl substituents, high thermal stability was observed via TGA.
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Synthesis of advanced adamantane containing intermediates based on para-bis (2-thienyl) phenylene. Influence of intramolecular hydrogen bonds on photoisomerization
Veselý, Dominik ; Pospíšilík, Karel (oponent) ; Krajčovič, Jozef (vedoucí práce)
This diploma thesis describes study and onward synthesis of advanced organic structures with potential application in the field of organic electronics and, in particular, molecular photoswitches. In the theoretical part of the thesis are closely described most commonly used conventional molecular photoswitches with special attention to the influence of the structural modifications on properties and applications of the given derivatives. Next passage is dedicated to study of donor-acceptor systems, as fundamental building blocks for synthesis of advanced derivatives. The possibilities of derivatization with a goal of improving the physicochemical properties of these compounds are also discussed. In the final chapter are proposed modern synthetic methods for preparation of novel materials for organic electronics. This section is connected with an experimental part, where are designed and consequently synthesised 4 novel imine derivatives with dodecyl and adamantyl-ethyl side chain.
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