Donor-acceptor C₆₀-containing polyferrocenylsilanes: Synthesis, characterization, and applications in photodiode devices

A series of polyferrocenylsilane (PFS) random copolymers containing covalently bound pendant [C₆₀]fullerene groups, the first well-characterized metallopolymers with pendant C₆₀ units, have been prepared and characterized. The fullerene content of the prepared copolymers ranges from 7 to 24% relative to monomer unit. The desired copolymers were synthesized in three steps: metal-catalyzed ring opening polymerization of sila[1]ferrocenophanes was performed to synthesize random copolymers of poly(ferrocenylmethylphenylsilane-co-ferrocenylchloromethylsilane); the resulting random PFSs were then functionalized by reaction with 11-azido-1-undecanol to give PFSs with pendant azide groups; the desired donor-acceptor C₆₀-containing PFSs were then synthesized by the reaction of the azide group in the side chains with C₆₀ in toluene at 110°C. The resulting C₆₀-containing PFSs are air-stable and soluble in aromatic solvents, chloroform, or THF. The UV-vis spectra of these materials show broad absorption up to 800 nm. Thin films of these materials were examined as the active layer in rare examples of all solid-state sandwich-type diode devices based on ferrocene-fullerene dyads. The devices exhibit photoconducting and photovoltaic responses, with an open circuit potential of ca. 0.3 V under white light illumination.