We thank the EPSRC, the Royal Society and the European Commission (THREADMILL – MRTN-CT-2006-036040) for financial support. One of the authors (S. B.) acknowledges support from the Fondazione Angelo Della Riccia.
Cyclodextrin-Threaded Conjugated Polyrotaxanes for Organic Electronics: The Influence of the Counter Cations†
Article first published online: 23 JUL 2008
Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Functional Materials
Volume 18, Issue 16, pages 2419–2427, August 22, 2008
How to Cite
Latini, G., Parrott, L.-J., Brovelli, S., Frampton, M. J., Anderson, H. L. and Cacialli, F. (2008), Cyclodextrin-Threaded Conjugated Polyrotaxanes for Organic Electronics: The Influence of the Counter Cations. Adv. Funct. Mater., 18: 2419–2427. doi: 10.1002/adfm.200800120
- Issue published online: 19 AUG 2008
- Article first published online: 23 JUL 2008
- Manuscript Revised: 2 MAY 2008
- Manuscript Received: 24 JAN 2008
- Royal Society
- European Commission (THREADMILL). Grant Number: MRTN-CT-2006-036040
Vol. 19, Issue 23, Article first published online: 3 DEC 2009
A systematic investigation is reported into the influence of the counter cations on the optical, electrical and electroluminescent properties of polyelectrolytic conjugated polymers and of their cyclodextrin-threaded rotaxanes. We compare conjugated polyelectrolytes with sulfonated side groups where the anionic charge is balanced by Li+, K+, Cs+, tetramethylammonium (Me4N+) and cryptate-encapsulated potassium (K+@[2.2.2]). Narrowing (for the unthreaded analogues) and a slight red-shift of the absorption spectra (for the rotaxanes) are found upon exchange of Li+ for larger cations, together with a blue-shift and an efficiency enhancement of the luminescence. These effects are similar in nature to those induced by rotaxination, and are therefore assigned to a marked reduction of intermolecular interactions between the conjugated cores. Exchange of Li+ for K+, Cs+, or Me4N+ results in a higher electroluminescence external quantum efficiency (EQE) for both polyrotaxanes and unthreaded polymers. For polyrotaxane-based devices the EQE increased approximately 7 times upon substitution of Li+ with Cs+ or Me4N+, thereby demonstrating the importance of the selection of the counter-cations for optimizing the performance of polyelectrolytic conjugated polymers in light-emitting devices.