Adsorption and charge-transfer study of bi-isonicotinic acid on in situ-grown anatase TiO2 nanoparticles

• Bi-isonicotinic acid (2,2'-bipyridine-4,4'-dicarboxylic acid) is an important ligand in the chemistry of organometallic devices. Here, the adsorption of a monolayer of the molecule on in situ-grown anatase TiO2 nanoparticles has been investigated by means of X-ray photoemission spectroscopy and X-ray absorption spectroscopy. The bonding geometry is determined to be 2M-bidentate. Furthermore, resonant core spectroscopies have been used to study the excited-state-dependent electron transfer from the core-excited molecule to the substrate. For an excitation to the lowest unoccupied orbital, the excited electron is localized on the molecule because of a core-excitonic effect. Excitation to the two following unoccupied orbitals leads to a charge transfer on a low-femtosecond time scale. This study shows that there is no essential difference in charge-transfer characteristics, compared to the case of adsorption on the rutile (110) surface, for states degenerate with the conduction band.

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

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