Christophe Jean Alexandre Barbe

Efficient Lateral Electron Transport inside a Monolayer of Aromatic Amines Anchored on Nanocrystalline Metal Oxide Films.

A monolayer of a phosphonated triarylamine adsorbed on nanocrystalline TiO2, ZrO2, or Al2O3 film deposited on conducting glass displays reversible electrochemical and electrochromic behavior although the redox potential of the electroactive molecules (0.80 V vs NHE) lies in the forbidden band of the semiconducting or insulating oxides. The mechanism of charge transport was found to involve hole injection from the conducting support followed by lateral electron hopping within the monolayer. The apparent diffusion coefficient ranged from 2.8 × 10(-12) m(2) s(-1) in the neat 1-ethyl-2-methylimidazolium bis(trifluoromethylsulfonyl)imide (EtMeIm(+)Tf2N(-)) to 1.1 × 10(-11) m(2) s(-1) in acetonitrile + 2 M EtMeIm(+)Tf2N(-). A percolation threshold for electronic conductivity was found at a surface coverage corresponding to 50% of a full monolayer.

Crystal structures of metal complex sensitizers of TiO2 nanopowders

The x-ray structure determination of three efficient Ru complex sensitizers of TiO2 nanopowders was carried out. The coordination of Ru was analyzed in terms of asymmetric ligand surrounding of metal atom and influence of chelate (pi) -conjugated ligands on the bonding of Ru with ligands and on the intermolecular association of complexes. The layered character of all three studied crystal structures could be correlated with the peculiarities of their molecular structures (polarity, presence of (pi) -conjugated moieties), what opens the possibility of using of molecular engineering methods to influence the anchoring and ordering of sensitizer molecules on semiconductor surfaces.

Synthesis of Superconducting Thin Films by Organometallic Decomposition

These Ecole polytechnique federale de Lausanne EPFL, n° 1003 (1992) Reference doi:10.5075/epfl-thesis-1003Print copy in library catalog Record created on 2005-03-16, modified on 2016-08-08