TY - JOUR
T1 - Unraveling excited-state dynamics in a polyfluorene-perylenediimide copolymer
AU - Fron, Eduard
AU - Deres, Ania
AU - Rocha, Susana
AU - Zhou, Gang
AU - Müllen, Klaus
AU - De Schryver, Frans C.
AU - Sliwa, Michel
AU - Uji-i, Hiroshi
AU - Hofkens, Johan
AU - Vosch, Tom
PY - 2010/1/1
Y1 - 2010/1/1
N2 - Insight into the exciton dynamics occurring in a polyfluorene- perylenediimide (PF-PDI) copolymer with a reaction mixture ratio of 100 fluorene units to 1 N,N′-bis(phenyl)-1,6,7,12-tetra(p-fert-octylphenoxy)- perylene3,4,9,10-tetracarboxylic acid diimide (PDI) is presented here. Time-correlated single photon counting and femtosecond transient absorption spectroscopy measurements on the PF-PDI copolymer have been employed to investigate the excited-state properties of the polyfluorene subunit where the exciton is localized (PF) and the incorporated PDI chromophore. The experimental results were compared with those obtained from a polyfluorene polymer (model PF) and a N,N′-bis(2,6-diisopropylphenyl)-1,6,7,12-tetra(p-fert- octylphenoxy)perylene-3,4,9,10-tetracarboxylic acid diimide (model PDI) which were used as reference compounds. Because of the high polydispersity of the PF-PDI copolymer, there is a polymer fraction present that contains no PDI chromophores (polyfluorene polymer fraction (PF polymer fraction)) and wide-field imaging of single polymers chains of the synthesized PF-PDI copolymer was used to estimate this PF polymer fraction. Following the primary excitation of the PF in the PF-PDI copolymer, energy hopping between PF's can occur. A fraction of the energy of the absorbed photons will be transferred to a PDI chromophore via energy transfer from a PF. In a polar solvent, a charge transfer state having the Si of the PDI moiety as a precursor state is found to form with high efficiency on a nanosecond time scale. The data suggest that a fraction of the absorbed energy is directed, transferred and used in charge separation, providing a clear view of a multistep mechanism of exciton dissociation into charges.
AB - Insight into the exciton dynamics occurring in a polyfluorene- perylenediimide (PF-PDI) copolymer with a reaction mixture ratio of 100 fluorene units to 1 N,N′-bis(phenyl)-1,6,7,12-tetra(p-fert-octylphenoxy)- perylene3,4,9,10-tetracarboxylic acid diimide (PDI) is presented here. Time-correlated single photon counting and femtosecond transient absorption spectroscopy measurements on the PF-PDI copolymer have been employed to investigate the excited-state properties of the polyfluorene subunit where the exciton is localized (PF) and the incorporated PDI chromophore. The experimental results were compared with those obtained from a polyfluorene polymer (model PF) and a N,N′-bis(2,6-diisopropylphenyl)-1,6,7,12-tetra(p-fert- octylphenoxy)perylene-3,4,9,10-tetracarboxylic acid diimide (model PDI) which were used as reference compounds. Because of the high polydispersity of the PF-PDI copolymer, there is a polymer fraction present that contains no PDI chromophores (polyfluorene polymer fraction (PF polymer fraction)) and wide-field imaging of single polymers chains of the synthesized PF-PDI copolymer was used to estimate this PF polymer fraction. Following the primary excitation of the PF in the PF-PDI copolymer, energy hopping between PF's can occur. A fraction of the energy of the absorbed photons will be transferred to a PDI chromophore via energy transfer from a PF. In a polar solvent, a charge transfer state having the Si of the PDI moiety as a precursor state is found to form with high efficiency on a nanosecond time scale. The data suggest that a fraction of the absorbed energy is directed, transferred and used in charge separation, providing a clear view of a multistep mechanism of exciton dissociation into charges.
U2 - 10.1021/jp909295h
DO - 10.1021/jp909295h
M3 - Article
AN - SCOPUS:76249133336
SN - 1520-6106
VL - 114
SP - 1277
EP - 1286
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 3
ER -