Elaboration caracterisation and study of physico-chemical properties of conducting materials for solide state organic dye sensitized solar cells

• Auteur / Autrice : Adel Jarboui
• Direction : Mohamed Jouini, Anders Hagfeldt
• Type : Thèse de doctorat
• Discipline(s) : Chimie
• Date : Soutenance en 2015
• Etablissement(s) : Sorbonne Paris Cité
• Ecole(s) doctorale(s) : École doctorale Chimie physique et chimie analytique de Paris Centre (Paris ; 2000-....)
• Partenaire(s) de recherche : Autre partenaire : Université Paris Diderot - Paris 7 (1970-2019)
• Jury : Rapporteur / Rapporteuse : André-Jean Attias

Mots clés

Mots clés contrôlés

Photopiles

Conducteurs organiques

Cellules solaires à colorant

Mots clés libres

Cellules solaires

Photovoltaïque

Cellules de Grätzel

Résumé

Dans ce travail, nous développons des cellules solaires à colorant dites cellules de Grâtzel (DSSC) où nous avons remplacé le couple redox transporteur de trous 131I- par un polymère conducteur (PC) généré par photopolymérisation électro-assistée in situ (PEP). Ni l'utilisation d'un PC comme transporteur de trou, ni celle de le produire par PEP d'un monomère oxydable ne constituent une nouveauté. Néanmoins, l'innovation dans notre travail consiste en deux points: i) Utiliser pour la première fois l'eau comme solvant au lieu d'un solvant organique (acétonitrile) pour générer le PC par PEP. L'eau permet d'abaisser drastiquement le potentiel d'oxydation des monomères organiques. Cet abaissement de potentiel permet d'utiliser un monomère commercial le 3,4-éthylènedioxythiophène au lieu de son dimère beaucoup plus cher et utilisé jusque-là dans pour les processus de PEP à cause de son faible potentiel d'oxydation. Ii)Utiliser des colorants purement organiques pour réaliser le processus PEP ce qui a permis d'améliorer considérablement le rendement de ces cellules. Les colorants organométalliques à base de Ru se sont avérés moins stable et donc moins efficaces dans les processus PEP aussi bien dans tous les milieux étudiés. Les résultats de notre travail sont inédits et grâce à cette méthode écologique, innovante et facile à mettre en œuvre, nous avons pu obtenir des cellules ayant de bons rendements et dont le coût peut être réduit considérablement par l'utilisation d'un colorant organique à faible coût de synthèse.

In this work, we have develop dye sensitized solar cens namely Grâtzel cells (DSSC), where we have replaced the 1371'' redox couple used as hole transporting material (HTM), by a conducting polymer (CP) generated using in situ electro¬assisted photopolymerization (PEP). The use of a CP as HTM, nor the production of CP by PEP of oxidizable monomer do not constitute a novelty. However, innovation in our work consists of two points: i)Use of water as a solvent for the first time, instead of organic ones (acetonitrile) to generate the PC by PEP. The water lowers drastically the oxidation potential of the organic monomers. This lowering of oxidation potential allows to use a commercial monomer 3,4-ethylenedioxythiophene instead of its dimer much more expensive, which is used hitherto in for the PEP process because of its low oxidation potential. Ii)Use of purely organic dyes to achieve the PEP process allowing a significant improve of the performance of these cells. Ru-based organometallic dyes were found to be less stable and therefore less effective in the PEP process in both media. The results of our work are unreleased and with this ecological, innovative and easy-to-implement method, we have obtained cells having good yields and the cost of which can be significantly reduced by the use of an organic dye of low-cost synthesis. The redox potentials of each of these two dyes. It emerges that: i) the use of the aqueous medium used to prepare the polymer PEP EDOT monomer, which is almost impossible in organic medium, and ii) that the two parameters to be considered to perform a process in situ PEP leading to a good conductive polymer, are the oxidation potential (or rather of the beginning of oxidation) of the monomer and the redox potential of the dye; the former must be lower than the second. The fourth chapter of the manuscript corresponding to the fourth publication. - Solid-State Dye-Sensitized Solar Cells Based on Poly (3,4-ethylenedioxypyrrole) and Metal-Free Organic Dyes Two organic dyes and the D35 D21L6 tested and yields of cells obtained are compared with those obtained from to tell-based PEDOP obtained using the Z907. All redox potentials of these dyes are higher than the oxidation potential of EDOP, which is favorable for E CEP in situ process of this monomer. The DSSCs based D35 gives a yield (4. 34%) higher than the yield of cell-based D21L6 (3. 05%) and performance of cells made of Z907 (0. 46%). This difference is attributed to the difference in redox potential of these dyes (D35 1. 16V / SHE D21L6 1. 10 V / V 1. 05 Z907 and ESH / ESH) following the same order of photoconversion efficiencies corresponding DSCs. These results confirm that the oxidation potential of the monomer and the redox potential of the dye are the two parameters that govern the efficiency of a PEP process on a TiO2 electrode modified with a dye and therefore have a direct influence on the photo-conversion efficiency of DSSCs. The manuscript ends with a conclusion in which Mr. Jarboui summarizes the results and presents perspectives. It proposes to continue to study the DSCs with the addition of additives that can improve yields or other monomers low oxidatior potential. These monomers can be studied to improve hole transport in solids DSSCs; eg polycarbazole known for his good character carrier holes.