The surface reduction of rutile TiO<inf>2</inf>(110) generates a state in the band gap whose excess electrons are spread among multiple sites, making the surface conductive and reactive. The charge extraction, hence the surface catalytic properties, depends critically on the spatial extent of the charge redistribution, which has been hitherto probed by small molecules that recombine at oxygen vacancy (O<inf>vac</inf>) sites. We demonstrate by valence band resonant photoemission (RESPES) a very general charge extraction mechanism from a reduced TiO<inf>2</inf>(110) surface to an extended electron-acceptor organic molecule. Perylene-tetra-carboxylic-diimide (PTCDI) is not trapped at O<inf>vac</inf> sites and forms a closely packed, planar layer on TiO<inf>2</inf>(110). In this configuration, the perylene core spills out the substrate excess electrons, filling the lowest unoccupied molecular orbital (LUMO). The charge transfer from the reduced surface to an extended π-conjugated system demonstrates the universality of the injection/extraction mechanism, opening new perspectives for the coupling of reducible oxides to organic semiconductors and supported catalysts. (Figure Presented).

Lanzilotto, V., Lovat, G., Fratesi, G., Bavdek, G., Brivio, G., Floreano, L. (2015). TiO<inf>2</inf>(110) Charge Donation to an Extended π-Conjugated Molecule. THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 6(2), 308-313 [10.1021/jz502523u].

TiO2(110) Charge Donation to an Extended π-Conjugated Molecule

BRIVIO, GIANPAOLO;
2015

Abstract

The surface reduction of rutile TiO2(110) generates a state in the band gap whose excess electrons are spread among multiple sites, making the surface conductive and reactive. The charge extraction, hence the surface catalytic properties, depends critically on the spatial extent of the charge redistribution, which has been hitherto probed by small molecules that recombine at oxygen vacancy (Ovac) sites. We demonstrate by valence band resonant photoemission (RESPES) a very general charge extraction mechanism from a reduced TiO2(110) surface to an extended electron-acceptor organic molecule. Perylene-tetra-carboxylic-diimide (PTCDI) is not trapped at Ovac sites and forms a closely packed, planar layer on TiO2(110). In this configuration, the perylene core spills out the substrate excess electrons, filling the lowest unoccupied molecular orbital (LUMO). The charge transfer from the reduced surface to an extended π-conjugated system demonstrates the universality of the injection/extraction mechanism, opening new perspectives for the coupling of reducible oxides to organic semiconductors and supported catalysts. (Figure Presented).
Articolo in rivista - Articolo scientifico
charge transfer, oxide. organic molecule, spectroscopy
English
2015
6
2
308
313
none
Lanzilotto, V., Lovat, G., Fratesi, G., Bavdek, G., Brivio, G., Floreano, L. (2015). TiO<inf>2</inf>(110) Charge Donation to an Extended π-Conjugated Molecule. THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 6(2), 308-313 [10.1021/jz502523u].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/59671
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