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Identifier

000395111

Title

Novel porphyrin-based photosensitizers with application in photovoltaic cells

Alternative Title

Νέοι πορφυρινικοί φωτοευαισθητοποιητές με εφαρμογή σε φωτοβολταϊκές κυψέλες

Author

Λαδωμένου, Καλλιόπη M.

Thesis advisor

Κουτσολέλος, Αθανάσιος

Reviewer

Μήλιος, Κωνσταντίνος
Δημάδης, Κωνσταντίνος

Abstract

The beauty and accuracy of light harvesting as well as the electron transfer process in natural photosynthesis are sources of inspiration for chemists, physicists and researchers of other disciplines to design artificial systems in order to convert solar energy into electricity or other forms of energy. More importantly, the understanding of the fundamentals of these processes is necessary in order to improve the design and the efficiency of artificial photoconversion systems, especially for photovoltaic applications. Porphyrins being ubiquitous in most of the natural pigments are an important building block for developing artificial molecular assemblies for solar photoconversion. The simplest mimicking unit of the natural photosynthetic center could be a porphyrin-derivative where an electron donor and an electron acceptor moiety are covalently linked or self-assembled via weak interactions. Intrinsic light-harvesting properties of porphyrins made them the best choice as sensitizers for organic photovoltaics, especially in photo-electrochemical dye-sensitized solar cells (DSSCs) or in hybrid solar cells. Twenty years after the discovery of DSSC by Grätzel, a porphyrin based sensitizer has exhibited one of the highest efficiency (~13%) reported so far. In this master research project our aim was the synthesis of novel porphyrin based photosensitizers for DSSC applications. The research has been divided in four subsections, where different types of porphyins have been prepared in order to be used as dyes in DSSCs. In Section A different triads have been synthesized bearing a central metallated porphyrin linked with (i) two free-base porphyrin molecules and (ii) with two boron dipyrrin (BDP) molecules. Their photophysical properties were studied. In section B the synthesis and DSCC measurements of two porphyrin dyads are presented. The porphyrinic molecules consist of a zinc-metalated porphyrin and a free-base porphyrin unit covalently linked at their peripheries. Power conversion efficiency values were measured for these dimers in the range of 4-5%. In section C dyad porphyrins were synthesized using ruthenium metalated porphyrins and their DSSC performance was measured in the range of 1 %. Finally, in section D metallated porphyrins were prepapred bearing long alkyl chains and two carboxylic groups attached at the meso position of the porphyrin ring via triple bond.

Language

English

Subject

Chromophore

Dye

Sensitizer

Solar cell

Ευαισθητοποιητής

Πορφυρίνη

Χρωμοφόρο

Χρωστική

Issue date