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Identifier 000411491
Title Μελέτη αυτοοργάνωσης υβριδικών χρωμοφόρων με αμινοξέα και πεπτίδια
Alternative Title Study on the self-assembly of hydrid chromophores with amino acids and peptides
Author Καρίκης, Κωνσταντίνος-Τσαμπίκος
Thesis advisor Κουτσολέλος, Αθανάσιος
Reviewer Μήλιος, Κωνσταντίνος
Τρικαλίτης, Παντελής
Κιτσόπουλος, Θεοφάνης
Μητράκη, Άννα
Αγγαρίδης, Παναγιώτης
Κυμάκης, Εμμανουήλ
Abstract Τhe function of artificial photosynthesis is based on light collection systems, composed of numerous chromophores, which self-organize through specific interactions, copying the self-organization of chlorophylls, into nano- and micro-structures with the ability to collect light. In the present study, a series of hybrid chromophores (porphyrin, BODIPY and corrole) were synthesized with diphenylalanine groups, which have been shown to form various microstructures (spheres, fibers etc), depending on the solvent system that is used to carry out self-organization. The morphology of the microstructures was examined by SEM, while their photophysical properties were examined with fluorescence and absorption spectroscopies. The properties of the microstructures were compared, in solution, solid and self-organized structure. The influence of the number of diphenylalanines attached to the chromophore, the chromophore binding pattern, the chromophore species, and the amino acid protecting group, were examined in the properties of the resulting nanostructures. All those nanostructures can behave as antennas, with superior properties compared to their solution and solid state forms, impressive absorption of light over nearly the whole visible range, exhibiting bathochromic shifts in the emission spectra indicating the formation of aggregates. The broadening of all absorption bands was particularly strong in the case of corroles (among the other substances that were tested). The fluorescence lifetimes of self-assembled species were longer as compared to the solid state form. Potential applications, exploiting the implementation of nature’s basic concept of self-organization of chromophores were created. A state of the art DSSC using solid electrolyte with a supramolecular system comprising of two porphyrins, a free base and its Zinc analogue, bearing diphenylalanine units, was constructed. The first is grafted onto the TiO2 surface and plays the role of the initiator for the self-assembly of the second, inducing the formation of multi-molecular self-assembled spherical microstructures. The achieved assemblies display antenna effect and are used as biomimetic chromophore systems for dye-sensitized solar cells (DSSCs). This self-assembled antenna system gives a proof of the concept that multichromophoric supramolecular assemblies based on hydrogen bonds can be of practical use for photovoltaic application. Finally, the synthesis with well-established straightforward reactions and high yields, of BODIPY-FF bioconjugates is outlined. Incorporation of FF peptide to BODIPY species, transfers combined their unique properties to the bioconjugates in order to create materials by means of self-assembly under mild conditions. SEM analysis confirmed and revealed the tendency of these bioconjugates to form spherical nanostructures upon self-assembly in acetonitrile/H2O. The importance of the FF protecting group as well as the solvent, was verified by the different resulting architectures (i.e. different sphere diameter, homogeny or formation of fibrilar microstructures in the case of Boc) and varied photophysical properties upon implementation of different solvent systems, for the formation of the microstructures. The photophysical study with bathochromic shifts also confirmed the formation of J-aggregates with reversible nature. To the best of our knowledge, this is the first example of chirality transfer from a chiral dipeptide to an achiral BODIPY upon self-assembly. Summarizing, we demonstrated that the molecular design along with the selection of building blocks are essential aspects that control the nature and the photophysical properties of BODIPY-FF conjugates so as to create smart nanomaterials with enhanced properties.
Language Greek
Subject Aggregates
Artificial photosynthesis
BODIPY
Corrole
Diphenylalanine
Nanostructures
Porphyrin
Self- Assembly
Διφαινυλαλανίνη
Κορρόλη
Πορφυρίνη
Συσσωματώματα
Συτοσυγκρότηση
Τεχνητή φωτοσύνθεση
Χρωμοφόρα
Issue date 2019-06-03
Collection   Faculty/Department--Faculty of Sciences and Engineering--Department of Chemistry--Doctoral theses
  Type of Work--Doctoral theses
Permanent Link https://elocus.lib.uoc.gr//dlib/6/4/5/metadata-dlib-1505208818-325916-4235.tkl Bookmark and Share
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