TY - JOUR
T1 - Lateral electron transport inside a monolayer of derivatized fullerenes anchored on nanocrystalline metal oxide films
AU - Papageorgiou, N.
AU - Grätzel, M.
AU - Enger, Olivier
AU - Bonifazi, Davide
AU - Diederich, François
N1 - Publication code : RES. ACAD.
PY - 2002
Y1 - 2002
N2 - Carboxylated fullerene derivatives adsorbed on nanocrystalline ZrO2 films deposited on conducting glass, display reversible electrochemical behavior with currents being 200 times higher than measured on a monolayer of the redox active fullerene molecule adsorbed on the conducting support. Despite the insulating oxide layer on which the fullerene is adsorbed, cross-surface charge transfer results in the participation of the internal surface of the oxide in the redox process. A mechanism of charge transport involving electron injection from the conducting support, followed by lateral electron hopping within the fullerene monolayer on the oxide, is proposed. Apparent diffusion coefficients as high as 1.5 × 10-8 cm2 s-1 were measured for the electron hopping process. A percolation threshold for electronic conductivity was found at a surface coverage between 40 and 60% of a full monolayer. Co-adsorbed spacer molecules, however, were seen to modify the percolation limit, as no threshold was observed up to 60% fullerene coverage. Significant implications are envisaged with regard to prospective applications in e.g. nano-optoelectronics, electrochemical devices, sensors, solar cells, and redox targeting of adsorbed biomolecules.
AB - Carboxylated fullerene derivatives adsorbed on nanocrystalline ZrO2 films deposited on conducting glass, display reversible electrochemical behavior with currents being 200 times higher than measured on a monolayer of the redox active fullerene molecule adsorbed on the conducting support. Despite the insulating oxide layer on which the fullerene is adsorbed, cross-surface charge transfer results in the participation of the internal surface of the oxide in the redox process. A mechanism of charge transport involving electron injection from the conducting support, followed by lateral electron hopping within the fullerene monolayer on the oxide, is proposed. Apparent diffusion coefficients as high as 1.5 × 10-8 cm2 s-1 were measured for the electron hopping process. A percolation threshold for electronic conductivity was found at a surface coverage between 40 and 60% of a full monolayer. Co-adsorbed spacer molecules, however, were seen to modify the percolation limit, as no threshold was observed up to 60% fullerene coverage. Significant implications are envisaged with regard to prospective applications in e.g. nano-optoelectronics, electrochemical devices, sensors, solar cells, and redox targeting of adsorbed biomolecules.
U2 - 10.1021/jp012657s
DO - 10.1021/jp012657s
M3 - Article
SN - 1520-6106
VL - 106
SP - 3813
EP - 3822
JO - The Journal of Physical Chemistry B
JF - The Journal of Physical Chemistry B
IS - 15
ER -