info:eu-repo/semantics/article
Let Digons be Bygones: The Fate of Excitons in Curved π-Systems
Fecha
2018-12Registro en:
Ondarse Alvarez, Dianelys; Nelson, Tammie; Lupton, John M.; Tretiak, Sergei; Fernández Alberti, Sebastián; Let Digons be Bygones: The Fate of Excitons in Curved π-Systems; American Chemical Society; Journal of Physical Chemistry Letters; 9; 24; 12-2018; 7123-7129
1948-7185
CONICET Digital
CONICET
Autor
Ondarse Alvarez, Dianelys
Nelson, Tammie
Lupton, John M.
Tretiak, Sergei
Fernández Alberti, Sebastián
Resumen
We explore the diverse origins of unpolarized absorption and emission of molecular polygons consisting of π-conjugated oligomer chains held in a bent geometry by strain controlled at the vertex units. For this purpose, we make use of atomistic nonadiabatic excited-state molecular dynamics simulations of a bichromophore molecular polygon (digon) with bent chromophore chains. Both structural and photoexcited dynamics were found to affect polarization features. Bending strain induces exciton localization on individual chromophore units of the conjugated chains. The latter display different transition dipole moment orientations, a feature not present in the linear oligomer counterparts. In addition, bending makes exciton localization very sensitive to molecular distortions induced by thermal fluctuations. The excited-state dynamics reveals an ultrafast intramolecular energy redistribution that spreads the exciton equally among spatially separated chromophore fragments within the molecular system. As a result, digons become virtually unpolarized absorbers and emitters, in agreement with recent experimental studies on the single-molecule level.