Optical excitations in star-shaped fluorene molecules

Montgomery, N. A., Denis, J.-C., Schumacher, S., Ruseckas, A., Skabara, P. J. , Kanibolotsky, A., Paterson, M. J., Galbraith, I., Turnbull, G. A. and Samuel, I. D. W. (2011) Optical excitations in star-shaped fluorene molecules. Journal of Physical Chemistry A, 115(14), pp. 2913-2919. (doi: 10.1021/jp1109042) (PMID:21428384)

Abstract

A detailed study of the low-energy optical transitions in two families of star-shaped molecules is presented. Both families have 3-fold rotational symmetry with oligofluorene arms attached to a central core. In one family, the core of the molecule is a rigid meta-linked truxene, while the other is a meta-linked benzene moiety. The low-energy transitions were studied both experimentally and using time-dependent density functional theory (TD-DFT). The optical transitions of these new star-shaped molecules were compared with corresponding linear oligofluorenes. Both families of star-shaped molecules showed higher absorption and fluorescence dipoles and photoluminescence quantum yields than straight chain oligofluorenes. TD-DFT calculations show that absorption takes place across the entire molecule, and after excited state relaxation, the emission results from a single arm. In both theory and experiment the transition dipole moments show an approximate n0.5 dependence on the number of fluorene units in each arm.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Skabara, Professor Peter and Kanibolotskyy, Dr Oleksandr
• Authors: Montgomery, N. A., Denis, J.-C., Schumacher, S., Ruseckas, A., Skabara, P. J., Kanibolotsky, A., Paterson, M. J., Galbraith, I., Turnbull, G. A., and Samuel, I. D. W.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Journal of Physical Chemistry A
• Publisher: American Chemical Society
• ISSN: 1089-5639
• ISSN (Online): 1520-5215
• Published Online: 23 March 2011