DOI: 10.1002/adfm.200700813 Electroactive Polymeric Networks Created by Oxidation of Oligothiophene-Functionalized Perylene Bisimides** By Chang-Cheng You, Pamela Espindola, Catharina Hippius , Jürgen Heinze, and Frank Würthner* 1. Introduction The combined engagement of electron-donor and electron- acceptor dyes can generate functional materials that possess unique optical and electronic properties, which have found ap- plications in various fields, including xerographic and photore- fractive materials, [1] ambipolar field-effect transistors, [2] and photovoltaic devices. [3] In most of these applications, the con- struction is based on a simple mixing of the required functional components in bulk material. [1–4] One inherent drawback of this approach is that the donor and acceptor molecules incline to stack on one another, thereby resulting in charge-transfer as- semblies, instead of the more desirable segregation of donor and acceptor components on a nanoscale. [5] Accordingly, the methods that can generate highly ordered donor-acceptor het- erojunctions are desired. Recently, various supramolecular approaches have been employed to get control over the ar- rangement of such dye junctions. [6,7] For example, hydrogen bonding and p-p interactions have been used to direct the self- assembly of oligo(p-phenylene vinylene) (OPV) and perylene bisimide dyes into structurally well-defined p-stacked co-aggre- gates that afford photoinduced charge carrier generation and ambipolar charge carrier transport in field-effect transistors. [7] More recently, Fukushima, Aida, and co-workers have created photoconductive coaxial nanotubes by controlled self-assembly of electron-deficient trinitrofluorenone (TNF)-tethered elec- tron-rich hexabenzocoronene (HBC), which exhibit a large on/ off ratio (> 10 4 ) of photoconductive response. [8] Perylene bisimides have been extensively used as electronic materials in recent years due to their unique optical, redox, and stability properties. [9,10] Attractively, they have been known as semiconductors with the highest n-type charge car- rier mobility available to date. [11] On the other hand, thio- phenes and oligothiophenes have found vast applications in op- toelectronic devices as electron-donating building blocks, which display excellent p-type charge carrier mobility. [12,13] Although the incorporation of those two classes of organic dyes would lead to interesting p-n-heterojunctions, the oligo- thiophene-perylene bisimide conjugates have rarely been reported. [14–16] Recently, we have fabricated oligothiophene-functionalized perylene bisimides and explored preliminarily their electro- chemical polymerization. [15] More recently, Zhu and co-work- ers and Segura, Bäuerle, and co-workers have also reported oligothiophene-perylene bisimide conjugates that show attrac- tive p- and n-conductive behavior. [16] Lee et al. have prepared pyrrole-appended perylene bisimides that can be transformed 3764 © 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Adv. Funct. Mater. 2007, 17, 3764–3772 – [*] Prof.F. Würthner, Dr. C.-C. You, C. Hippius Institut für Organische Chemie and Röntgen Research Center for Complex Material Systems Universität Würzburg Am Hubland, 97074 Würzburg (Germany) E-mail: wuerthner@chemie.uni-wuerzburg.de P. Espindola, Prof. J. Heinze Institut für Physikalische Chemie Universität Freiburg Albertstrasse 21, 79104 Freiburg (Germany) [**] We thank the Alexander von Humboldt Foundation (fellowship for C.C.Y.) and the Fonds der Chemischen Industrie (Kekulé fellowship for C.H.) for financial support, and BASF AG for the donation of chemicals. A series of fourfold oligothienyl-functionalized perylene bisimides, N,N′-bis(2,6-diisopropylphenyl)-1,6,7,12-tetra(4-(7- [2,2′]bithien-5-yl)-heptanoyloxyphenoxy)perylene-3,4:9,10-tetracarboxylic acid bisimide (7a), N,N′-bis(2,6-diisopropylphenyl)- 1,6,7,12-tetra(4-(7-[2,2′;5′,2′′]terthien-5-yl)-heptanoyloxyphenoxy)perylene-3,4:9,10-tetracarboxylic acid bisimide (7b), and N,N′-bis(2,6-diisopropylphenyl)-1,6,7,12-tetra(4-(7-(5″-Methyl-[2,2′;5′,2″]terthien-5-yl))-heptanoyloxyphenoxy)perylene-3,4:9,10- tetracarboxylic acid bisimide (7c), have been synthesized. Oligothienyl and perylene bisimide chromophores in these dyads dis- play their characteristic optical UV/vis absorption properties. Upon excitation of the oligothiophene subunits, fluorescence res- onance energy transfer (FRET) occurs to the perylene bisimide core. Cyclic voltammetric studies revealed that the reduction of the perylene bisimide moiety is not affected by the presence of oligothiophenes, showing two waves at around -0.7 and -1.0 V versus Ag/AgCl, respectively. On the other hand, the oxidation of the oligothienyl moieties leads to oxidative coupling for 7a and 7b, providing electroactive sexithiophene- and quaterthiophene-perylene bisimide networks, respectively. Electrochemical deposition of compounds 7a,b was performed and the films were characterized using cyclic voltammetry and in situ conduc- tance, which reveal remarkable p-type conductivity. Significantly, two separate regimes of electrical conductance have been ob- served for the films generated from 7b. FULL PAPER