Oligothiophene linked fullerenes

There are several other recent reports on the synthesis (and possibility) of photoinduced electron transfer in supramolecules such as porphyrin linked C60 [146,147], norbomene linked C6o. [148], phthalocya-nine linked fullerene [149], Cu(I) complex linked fullerenes [150], aniline linked fullerenes [151] and oligothiophene linked fullerenes [152]. 

In the case of oligothiophene-fullerene dyads, oligothio-phene and fullerene moieties seem to be located at the closest position since both oligothiophene and fullerene moieties are hydrophobic. On the other hand, aniline-fullerene dyad is considered to form a spontaneous self-assembly in such a way that the hydrophobic fullerene moieties come together, leaving the polar aniline moiety outside, in which the distance between aniline in a dyad and Qg in another dyad will be similar to that of the dyad molecule in solution. These findings indicate that the self-assembly of donor-acceptor linked molecules in the fine particles is an important factor governing the rates of the CS and CR processes. 

Due to the successful use of PCBM as acceptor material in solar cells, various attempts have been made to link Ceo covalently to an oligothiophene backbone in order to prepare D-A-based materials for photovoltaic devices by tuning their electronic properties [45, 46, 200, 201]. The attachment of fullerene units prevented large-scale phase separation in thin films and, despite the inclusion of bulky fullerene units, the soluble polymers retained their high order in thin films. However, the efficiency of such devices has been limited by competition between photoinduced electron transfer and energy transfer which occurs from the donor component to the fullerene. 

The first dyad molecule in which a fullerene was covalently linked to an oligothiophene 2.102 (Chart 1.20) was realized by Zotti elal. as a precursor for a corresponding polythiophene [202]. An azo... 

D. Hirayama, K. Takimiya, Y. Aso, T. Otsubo, T. Hasobe, H. Yamada, H. Imahori, S. Fukuzumi and Y. Sakata, Large photocurrent generation of gold electrodes modified with [60]fullerene-linked oligothiophenes bearing a tripodal rigid anchor, J. Am. Chem. Soc., 124, 532-533 (2002). 

T. Nakamura, J. Ikemoto, M. Fujitsuka, Y. Araki, O. Ito, K. Takimiya, Y. Aso and T. Otsubo, Control of photoinduced energy- and electron-transfer steps in zinc porphyrin-oligothiophene-fullerene linked triads with solvent polarity, J. Phys. Chem. B, 109, 14365-14374 (2005). 

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