Description succincte
(Anglais)
|
Within the present project, we propose to perform investigations on electron transport dynamics in functional nanostructured materials with the purpose of converting light energy. In order to increase the fundamental knowledge, the dynamical behavior of electrons in such functional materials will be scrutinized by different optical spectroscopic techniques. Concerning the performance, the research will be orientated toward the systematic evaluation of the potential for light energy conversion for each composition of nanostructured materials. The present program will be divided in three main tasks: A. Building of three dimensional mesoporous nanostructured electrodes consisting of conductive glass//metal oxide//noble metal//light harvesting units. B. Measurements of interfacial electron transfer rates by different optical spectroscopic techniques in order to establish the degree of competition between the channels of electron transport in the nanoarchitecture. C. Evaluation of the performance of the present photovoltaic devices. The incident photon-to-current conversion efficiency (IPCE) will be determined for each novel nanostructured solar cells. Finally, we plan to correlate the electron transport dynamics with the performance of the composite three dimensional nanostructured materials in order identifying the limiting step in the conversion of light energy.
|
Partenaires et organisations internationales
(Anglais)
|
AT, BE, BG, CH, CZ, DE, DK, ES, FI, FR, GR, HU, IE, IT, LV, NL, NO, PL, PT, RO, SE, SI, UK
|
Résumé des résultats (Abstract)
(Anglais)
|
During this project, we have focused our attention to the oxygen reduction reaction (ORR) that is very important in fuel cell design.The main achievements of the EPFL contribution to the working group have been the synthesis of hydrogen peroxide in biphasic systems using decamethylferrocene as an oxygen ligand. The reaction is controlled by the proton pump reaction from the aqueous to the organic phase. This reaction clearly demonstrates that oxygen reduction can take place at soft interfaces, thereby validating the proposed molecular approach. The concept of molecular interfacial catalysis was demonstrated using Cobalt Tetraphenylporphyrin (CoTPP) as a catalyst, aqueous protons and lipophilic electron donors such as ferrocene as reactants to reduce oxygen. In collaboration with the Czech group, we have shown that free base porphyrins such as H2TPP can also activate oxygen to catalyse its reduction. This is one of the first example a metal free catalyst. Finally, we have characterised highly efficient amphiphilic porphyrins for oxygen reduction synthesised by the French group.
|
