DOI: 10.1002/adfm.200700315 Donor–Acceptor C 60 -Containing Polyferrocenylsilanes: Synthesis, Characterization, and Applications in Photodiode Devices** By Masato Nanjo, Paul W. Cyr, Kun Liu, Edward H. Sargent, * and Ian Manners * 1. Introduction Metal-containing polymers [1–3] are attracting increased attention as luminescent, [4,5] redox-active, [6–10] conductive, [11] catalytic, [12,13] etch resistant [14,15] and self-assembled supra- molecular materials. [16,17] Polyferrocenylsilanes (PFSs) are a representative class of metallopolymers that possess numerous properties of interest for a variety of materials science applications. [18–20] Because of the presence of the ferrocenyl moiety in the polymer backbone, electrical properties of PFSs are of particular interest. PFSs have two reversible redox potentials due to electronic communications between neigh- boring iron centers. [21–23] Although their intrinsic conductiv- ities classify them as insulators, chemical oxidative doping of PFSs with iodine leads to an increase in conductivity of several orders of magnitude, into the range of 10 4 to 10 8 Scm 1 similar to semiconductors, and the doped materials possess p-type charge carriers. [24–27] Photo-oxidation of PFS films can also be achieved by near-UV light irradiation in the presence of chloroform vapor, and the photo-oxidized PFSs show a conductive nature (10 8 Scm 1 ) in the dark and a photoconductive response under illumination. [28] Charge transfer complexes containing ferrocenes have been well investigated in the context of conducting and magnetic materials. [29] However, Guldi and co-workers recently reported intramolecular photo-induced electron transfer in ferrocene (donor)/fullerene (acceptor) dyads, and the photo-excited dyads consisting of a ferrocene radical cation and fullerene radical anion reveal relatively long-lived charge separation dynamics (on the order of microseconds). [30] These phenomena are very interesting for potential applications as photo-active materi- als. [31–37] However, such applications have most often been studied in solution or in thin films incorporated into photoelec- trochemical cells containing electrolytic solutions. Very recently, we have described photoconductive and photovoltaic properties in solid-state devices made with PFS/fullerene composite thin films. [38] Although some platinum- or ruthenium-containing conjugated polymers have been synthesized and demonstrate photoluminescent, [39–41] photoconductive, [39] and photovoltaic properties, [42,43] examples of such devices based on metal- containing polymers are limited. Furthermore, while varieties of polymers incorporating fullerenes into backbones, side-chains, and end-groups have been reported, [44] linear metallopolymers bearing fullerene groups are unexplored. We report herein the synthesis of PFS- containing covalently bound C 60 units and their application in photodiode devices. FULL PAPER A series of polyferrocenylsilane (PFS) random copolymers containing covalently bound pendant [C 60 ]fullerene groups, the first well-characterized metallopolymers with pendant C 60 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 C 60 -containing PFSs were then synthesized by the reaction of the azide group in the side chains with C 60 in toluene at 110 8C. The resulting C 60 -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. [*] Prof. E. H. Sargent, Dr. P. W. Cyr Department of Electrical and Computer Engineering University of Toronto 10 King’s College Road, Toronto, ON M5S 3G6 (Canada) E-mail: ted.sargent@utoronto.ca Prof. I. Manners School of Chemistry University of Bristol Bristol, BS81TS (UK) E-mail: ian.manners@bristol.ac.uk Prof. I. Manners, Dr. M. Nanjo, [+] K. Liu Department of Chemistry University of Toronto 80 St. George Street, Toronto, ON M5S 3H6 (Canada) [+] Present address: Department of Materials Science, Faculty of Engin- eering, Tottori University, Japan. [**] I.M. thanks the European Union for a Marie Curie Chair and the Royal Society for a Wolfson Research Merit Award. E.H.S. thanks the Canadian Government for a Canada Research Chair. M.N. thanks the Ministry of Education, Culture, Sports, Science and Technology Japan for Overseas Advanced Educational Research Practice Support Program. We are also grateful to Ethan J. D. Klem, Dr. Tim Burrow, Georgeta Masson, Kyoung Taek Kim, and Hai Wang for their contri- butions to the characterization of the described materials. 470 ß 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Adv. Funct. Mater. 2008, 18, 470–477