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Exciton dissociation in conjugated polymers
Author(s) -
Arkhipov Vladimir,
Bässler Heinz,
Emelyanova Evgenia,
Hertel Dirk,
Gulbinas Vidmantas,
Rothberg Lewis
Publication year - 2004
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200450802
Subject(s) - dissociation (chemistry) , metastability , exciton , electric field , photoionization , conjugated system , chemical physics , polymer , photochemistry , materials science , chemistry , quenching (fluorescence) , photoconductivity , molecular physics , fluorescence , condensed matter physics , physics , optoelectronics , optics , ionization , quantum mechanics , organic chemistry , ion
In conjugated polymers, a majority of photogenerated charges form metastable geminate pairs (GPs), of which only some fraction can dissociate completely. Both the yield of GP photogeneration and the probability of further dissociation of GPs into free charges depend upon an external electric field. In the present article we discuss several experimental methods to detect the existence of geminate pairs such as delayed field collection of charges, field quenching of fluorescence, and field‐assisted photoinduced optical absorption. It is shown that the field dependences of the exciton dissociation into GPs and of the free carrier photogeneration yield are rather similar. This is in contrast with the traditional Onsager theory, which assumes field‐independent yield of primary photoionization and disregards the field dependence of the initial separations between carriers in GPs.