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Exciton Migration and Surface Trapping for a Photonic Crystal Displaying Charge-Recombination Fluorescence

Lookup NU author(s): Roza Al-Aqar, Dr Alparsan Atahan, Professor Andrew Benniston, Thomas Perks, Dr Paul Waddell, Emeritus Professor Anthony Harriman



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Wiley - VCH Verlag GmbH & Co. KGaA, 2016.

For re-use rights please refer to the publisher's terms and conditions.


A compact donor–acceptor molecular dyad has been synthesized by attaching an N,N-dimethylamino fragment to a naphthalic anhydride residue. The dyad shows fluorescence from an intramolecular charge-transfer state (i.e., charge-recombination fluorescence) in solution, with the photo-physical properties being strongly dependent on the solvent polarity. Similar emission is seen for single crystals of the target compound, the molecules being aligned head-to-head, although time-resolved emission profiles display dual-exponential kinetics. A second polymorph with the head-to-tail alignment also gives rise to two lifetimes that differ somewhat from those of the first structure, which are assigned to bulk and surface-bound molecules. Growing the crystal in the presence of Rhodamine B localizes the dye around the surface. Excitation of the crystal is followed by sub-ps exciton migration along the aligned stacks, with occasional crossing to adjacent stacks and trapping at the surface. Rhodamine B present at very low levels acts as the acceptor for excitons entering the surface layer. Crystals embedded in a polyester resin form an artificial light-harvesting antenna able to sensitize an amorphous silicon solar cell.

Publication metadata

Author(s): Al-Aqar R, Atahan A, Benniston AC, Perks T, Waddell PG, Harriman A

Publication type: Article

Publication status: Published

Journal: Chemistry: A European Journal

Year: 2016

Volume: 22

Issue: 43

Pages: 15420-15429

Print publication date: 17/10/2016

Online publication date: 06/09/2016

Acceptance date: 01/09/2016

Date deposited: 13/09/2016

ISSN (print): 0947-6539

ISSN (electronic): 1521-3765

Publisher: Wiley - VCH Verlag GmbH & Co. KGaA


DOI: 10.1002/chem.201602155


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