Self-trapping and excited state absorption in fluorene homo-polymer and copolymers with benzothiadiazole and tri-phenylamine
Abstract
Excited state absorption (ESA) is studied using time-dependent density functional theory and compared with experiments performed in dilute solutions. The molecules investigated are a fluorene pentamer, polyfluorene F8, the alternating F8 copolymer with benzothiadiazole F8BT, and two blue-emitting random copolymers F8PFB and F8TFB. Calculated and measured spectra show qualitatively comparable results. The ESA cross-section of co-polymers at its maximum is about three times lower than that of F8. The ESA spectra are found to change little upon structural relaxation of the excited state, or change in the order of sub-units in a co-polymer, for all studied molecules. In all these molecules, the strongest ESA transition is found to arise from the same electronic process, exhibiting a reversal of the charge parity. In addition, F8PFB and F8TFB are found to possess almost identical electronic behaviour.
Citation
Denis , J-C , Ruseckas , A , Hedley , G J , Matheson , A B , Paterson , M J , Turnbull , G A , Samuel , I D W & Galbraith , I 2016 , ' Self-trapping and excited state absorption in fluorene homo-polymer and copolymers with benzothiadiazole and tri-phenylamine ' , Physical Chemistry Chemical Physics , vol. 18 , no. 31 , pp. 21937-21948 . https://doi.org/10.1039/C6CP02059C
Publication
Physical Chemistry Chemical Physics
Status
Peer reviewed
ISSN
1463-9076Type
Journal article
Description
We thank the EPSRC [EP/J009318/1 and EP/J009016/1] for funding. MJP thanks the European Research Council (ERC) for funding under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant No. 258990.Collections
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