Guest-host interactions between dichroic dyes and anisotropic hosts.

Palsson, L.O.; Vaughan, H.L.; Smith, A.; Szablewski, M.; Cross, G.H.; Roberts, T.; Masutani, A.; Yasuda, A.; Beeby, A.; Bloor, D.

Abstract

The guest–host interaction between dichroic dyes and anistropic hosts has been investigated by means of optical spectroscopy. Two different TCNQ adducts; 2-{4-[(2,6-dimethylmorpholin-4-yl)(4-metylpiperidin-1-yl)methylene]cyclohexa-2,5-dien-1-ylidene} malononitrile (MORPIP) and 2-{4-[cyclohex-1-yltetrahydropyrimidin-2(1H-ylidene]cyclohexa-2,5-dien-1-ylidine} malononitrile (AMINO) have been examined dispersed in a range of nematic liquid crystal mixtures. The result is a substantial impact on the absorption and luminescence when compared to the situation in isotropic solvents. The excited state decay exhibits a complex behaviour showing a multi-exponential decay of the time-resolved luminescence. The photoluminescence quantum yields of the chromophores, also shows strong host dependence. For AMINO, we observe a trend which is indicative of a viscosity dependence. The observations are discussed in view of different solvent–solute interactions between guest and host.

• Journal Article Type: Article
• Publication Date: 2006-03
• Journal: Journal of Luminescence
• Print ISSN: 0022-2313
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 117
• Issue: 1
• Pages: 113-122
• DOI: https://doi.org/10.1016/j.jlumin.2005.03.017
• Keywords: Absorption, Anistropic host, Dichroic dyes, Guest–host interactions, Hydrogen bonds, Isomerisation, Isotropic solvent, Liquid crystals, Luminescence.
• Public URL: https://durham-repository.worktribe.com/output/1542293