A thorough investigation on the physicochemical properties, including electrochemisty and photophysics, of a new class of donor-acceptor hybrids, namely, phthalocyanine-fullerene dyads, consisting of free base la and zinc and copper complexes Ib and le, respectively, brings new insights into the stabilization of charge-separated radical ion pairs and the impact of redoxactive transition-metal centers on the photoperformance of macrocyclic phthalocyanines. In these dyads, the role of the phthalocyanines is twofold: First, it functions as an antenna (i.e., absorbing very efficiently light in the visible region of the solar spectrum) and, second, as a donor molecule-once photoexcited. The initial photoexcitation is succeeded by an ultrafast electron transfer largely due to the strong electronic coupling between electron donor (Pc) and electron acceptor (C 60) generating surprisingly long-lived radical ion pairs Pc •+-C 60 •- with lifetimes of several nanoseconds. Large driving forces for the charge recombination and small reorganization energies of the Pc-C 60 ensembles corroborate slow charge recombination dynamics, which, in turn, helps to rationalize the long lifetimes of Pc •+-C 60 •+.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry