Liquid crystalline organic semiconductors: nematic spiro[cyclopentyl-1,9']fluorenes

Billa, Muralidhar Reddy; Kassireddy, Krishna; Haro, Marta; Al-Kalifah, Manea S.; Kelly, Stephen M.; Kitney, Stuart P.; O'Neill, Mary

Abstract

A number of nematic spiro[cyclopentyl-1,9′]fluorene reactive mesogens with polymerisable oxetane or non-conjugated diene end-groups have been successfully synthesised. The melting and clearing points of these new spiro[cyclopentyl-1,9′]fluorenes are much higher than those of the corresponding 9,9-diethyl- or 9,9-dipropyl-substituted fluorenes, which are present in many light-emitting polymers currently used in polymer light-emitting diodes. The significant difference in transition temperature may be attributed to the lower intermolecular separation induced by the more rigid and less bulky cyclopentyl group, confirmed by molecular modelling. The presence of either these short but flexible aliphatic chains, or a rigid alicyclic group of similar size and shape, results in only small differences in the photoluminescence spectra and efficiency of these model liquid crystalline organic semiconductors, and in their improved thermal stability.

Citation

Billa, M. R., Kassireddy, K., Haro, M., Al-Kalifah, M. S., Kelly, S. M., Kitney, S. P., & O'Neill, M. (2011). Liquid crystalline organic semiconductors: nematic spiro[cyclopentyl-1,9']fluorenes. Liquid crystals, 38(7), 813-829. https://doi.org/10.1080/02678292.2011.577913

• Journal Article Type: Article
• Acceptance Date: Mar 31, 2011
• Online Publication Date: Jul 12, 2011
• Publication Date: 2011-07
• Journal: Liquid Crystals
• Print ISSN: 0267-8292
• Publisher: Taylor and Francis
• Peer Reviewed: Peer Reviewed
• Volume: 38
• Issue: 7
• Pages: 813-829
• DOI: https://doi.org/10.1080/02678292.2011.577913
• Keywords: Spiro-fluorenes; Nematics; Organic semiconductors,
• Public URL: https://hull-repository.worktribe.com/output/400295
• Publisher URL: https://www.tandfonline.com/doi/abs/10.1080/02678292.2011.577913