Fullerene-based Molecular Systems

Numerous studies have been concerned with refining our level of under- 

Standing about the basic photophysical properties of C6o, C70, and, to a lesser extent, C76 in fluid solution.Despite the enormous interest in these materials, there are still several unresolved issues that need to be clarified before full agreement is reached regarding the photophysics of the isolated compounds. Similarly, attention has been given to simple derivatives that are more soluble in polar solvents.The photophysical properties of fullerenes bound to solid surfaces and entrapped within zeolitic cages have also received attention. 

Standing about the basic photophysical properties of C o, C o, and, to a lesser extent, Cje in fluid solution. Despite the enormous interest in these 

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TTF-based D-A systems have been extensively used in recent years to play around photoinduced electron transfer processes. Typically, when an electron acceptor moiety that emits fluorescence intrinsically is linked to TTF (D), the fluorescence due to the A moiety may be quenched because of a photoinduced electron transfer process (Scheme 15.1). Accordingly, these molecular systems are potentially interesting for photovoltaic studies. For instance, efficient photoinduced electron transfer and charge separation were reported for TTF-fullerene dyads.6,7 An important added value provided by TTF relies on the redox behavior of this unit that can be reversibly oxidized according to two successive redox steps. Therefore, such TTF-A assemblies allow an efficient entry to redox fluorescence switches, for which the fluorescent state of the fluorophore A can be reversibly switched on upon oxidation of the TTF unit. 

Fulleropyrrolidines constitute an important family of Ceo derivatives that have the advantage over the methanofullerene systems in that they lead to stable reduced species, allowing the development of fullerene-based redox molecular switches. In order to promote mesomorphism in such a mono-adduct structure, Deschenairx et al. decided to modify the Ceo derivative by the use... 

The aim of this chapter is to give a state-of-the-art report on the plastic solar cells based on conjugated polymers. Results from other organic solar cells like pristine fullerene cells [7, 8], dye-sensitized liquid electrolyte [9], or solid state polymer electrolyte cells [10], pure dye cells [11, 12], or small molecule cells [13], mostly based on heterojunctions between phthaocyanines and perylenes [14], will not be discussed. Extensive literature exists on the fabrication of solar cells based on small molecular dyes with donor-acceptor systems (see for example [2, 3] and references therein). 

The first experiments were carried out on films of solid CeO) 100 to 1000 A thick, exposed to alkali metal vapors.[Ha91a ] It was observed that the conductivity increased by more than seven orders of magnitude, to 500 (fl cm) . This is still a much lower conductivity than any metallic element, but on the order of such organic systems as doped polyacetylene. Haddon et al. made the plausible suggestion, subsequently proved, that the smaller alkali ions were intercalated into the voids between the much larger fullerenes, and donated their charge to the unoccupied fullerene molecular orbital. The ratio of alkali atoms to fuUerenes in the (super) conducting phase was not then known, nor was it known whether the structure was based on the... 

Volume 1 contains 15 chapters on the recent developments in charge-transfer salts, fullerenes, photoconductors and molecular conductors. The topics covered include electron acceptor molecules, photo-induced intermolecular electron transfer systems, perylene based conductors, tetrachalcogenafulvalenes, metal 1,2-dichaIcogenoIenes and their conductive salts, conductive hetero-TCNQs (tetracyano-p-quinodi-methane derivatives), molecular metals and superconductors based on transition metal complexes. 

R167 M. lyoda, Y. Kuwatani, T. Nishinaga, M. Takase and T. Nishiuchi, Conjugated Molecular Belts Based on 3D Benzaannulene Systems , in Fragments of Fullerenes and Carbon Nanotubes Designed Synthesis, Unusual Reactions, and Coordination Chemistry, eds. M. A. Petrukhina and L. T. Scott, John Wiley Sons, Inc., Hoboken, N. J., 2012, p. 311. 

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