All-conjugated polyelectrolyteblock copolymers

Abstract

Novel, all-conjugated polyelectrolyte block copolymers of the rod-rod type can be generated in a ''grafting from'' scheme and exhibit a preferred tendency to self-assemble into layered aggregates both in solution and the solid state. Here, the rigid-rod structure of the individual, complex macromolecules favours the formation of low-curvature vesicular and lamellar aggregates. Our poly(9,9-dialkylfluorene)-b-poly [3-(6-ammoniumhexyl)thiophene] (PF2/6-b-P3TMAHT and PFO-b-P3TMAHT, where PF2/6 and PFO denote 2-(ethyl)hexyl and linear octyl alkyl pendant groups, respectively), and poly(9,9-dialkylfluorene)-b-poly[3-(6-pyridylhexyl)thiophene] (PF2/6-b-P3PyHT and PFO-b-P3PyHT) polyelectrolyte diblock copolymers allow for simple and reliable control of the occurring self-organisation process and the resulting nano-scaled architectures. They are, therefore, promising candidates for application as the active layer in electronic devices or as functional membranes (e.g. for sensor applications). Moreover, the electronic properties of the materials (especially the excitation energy transfer between both blocks) strongly depend on the aggregation state present. Aggregation can be further controlled via addition of oppositely charged surfactants resulting in the formation of ordered polyelectrolyte/surfactant complexes.

Molecular design of interfacial layers based on conjugated polythiophenes for polymer and hybrid solar cells

“…Scherf et al . have notably shown that amphiphilic conjugated block copolymers containing both hydrophobic polyfluorene and hydrophilic cationic P3HT blocks ( P5,Br ) (Scheme ) exhibit solvent‐ and charge‐mediated self‐assembly . Judicious selection of the polarity of the solvent mixture allows modulation of the nanomorphology of the self‐assembled aggregates (e.g.…”

“…vesicles, rods etc. ), as well as their optical properties . Due to its solubility in polar solvents, this conjugated block copolyelectrolyte was used as an electron‐extracting layer in BHJ‐OPV cells and its performance was compared to that of the corresponding ionic polythiophene homopolymer ( P1,Br ) .…”

Counterion Pinning in Conjugated Polyelectrolytes for Applications in Organic Electronics

“…Ullrich Scherf* conjugation · light-emitting diodes · organic electronics · polymers · zwitterions Cationic conjugated polyelectrolytes (cationic CPEs) [1,2] as components of electronic devices came in the focus of interest since the first demonstration of their potential as effective electron-injecting layers in organic light-emitting diodes (OLEDs) and organic field-effect transistors (OFETs). A further application in "bulk heterojunction"-type organic solar cells (OSCs) has also been reported.…”

Harnessing self-assembly strategies for the rational design of conjugated polymer based materials

“…2). 52 The hydrophilic nature of the polythiophene blocks leads to solvent-induced self-assembly in mixtures of selective and nonselective solvents, as observed for PF2/6-P3PHT in water-tetrahydrofuran (THF) or water-hexane 53 or PF2/6-b-P3TMAHT in water-THF 54 or water-MeOH. 55 Notably, the self-assembled structures generated in solution are transferred to the solidstate, such that PF2/6-b-P3TMAHT forms vesicular nanostructures in drop-cast lms prepared from low concentration methanolic solutions (0.03 mg mL À1 ) (Fig.…”

“…Films prepared from solutions at higher concentrations ($5 mg mL À1 ) lead to a denser coverage of the substrate and a transformation to solid state-like lms. 52 Atomic force microscopy (AFM) measurements reveal a transition from vesicular (region 1, Fig. 2a) to a lamellar morphology (region 3, Fig.…”