Microstructure tailoring of conjugated polymer-electrolyte blends for light-emitting electrochemical cells

• Published in: Solid state ionics Vol. 176; no. 19; pp. 1747 - 1751
• Main Authors: Wenzl, F.P., Pölt, P., Haase, A., Patil, S., Scherf, U., Leising, G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2005
• Subjects: Atomic force microscopy; Conjugated polymer; Light-emitting electrochemical cell; Phase-separation; Scanning electron microscopy; Conjugated polymer; Atomic force microscopy; Scanning electron microscopy; Light-emitting electrochemical cell; Phase-separation
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2005.04.037

We report on a strategy to reduce the size scale of the phase-separation in blends of conjugated polymers and solid state electrolytes. Blending a blue-green emitting conjugated polymer (methyl substituted ladder-type poly( p-phenylene), mLPPP) with a crown ether-based solid state electrolyte (Dicyclohexano18crown6 (DCH18C6), as an ion co-ordinating and transporting component and a Li salt, Lithium trifluoromethanesulfonate (Li triflate, LiTf for short) that provides the ionic species) evokes pronounced phase-separation. Endowing the backbone of mLPPP with convenient structural units largely reduces the size scale of this phase-separation. In particular we show that carbazole groups, which are generally applied in organic electronics to facilitate charge carrier transport, accessorily abate the tendency for phase-separation from a micro- to a sub-micro-scale. This attitude is investigated by UV/VIS/NIR absorption measurements, infrared spectroscopy, atomic force microscopy (AFM) and X-ray analysis by means of energy dispersive X-ray spectrometry (EDXS) in the scanning electron microscope (SEM).