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Interchain effects in the ultrafast photophysics of a semiconducting polymer: THz time-domain spectroscopy of thin films and isolated chains in solution

Hendry, E; Koeberg, M; Schins, J M; Nienhuys, Han-Kwang LU ; Sundström, Villy LU ; Siebbeles, L D A and Bonn, M (2005) In Physical Review B (Condensed Matter and Materials Physics) 71(12). p.1-125201
Abstract
We compare the generation and decay dynamics of charges and excitons in a model polymer semiconductor (MEH-PPV) in solution and drop-cast thin films, by recording the sub-ps transient complex conductivity using THz time-domain spectroscopy. The results show that the quantum efficiency of charge generation is two orders of magnitude smaller in solution (~10–5) than in the solid film (~10–3). The proximity of neighboring chains in the films apparently facilitates (hot) exciton dissociation, presumably by allowing the electron and hole to separate on different polymer strands. For both samples, photoexcitation leads to the predominant formation of bound charge pairs (excitons) that can be detected through their polarizability. Surprisingly,... (More)
We compare the generation and decay dynamics of charges and excitons in a model polymer semiconductor (MEH-PPV) in solution and drop-cast thin films, by recording the sub-ps transient complex conductivity using THz time-domain spectroscopy. The results show that the quantum efficiency of charge generation is two orders of magnitude smaller in solution (~10–5) than in the solid film (~10–3). The proximity of neighboring chains in the films apparently facilitates (hot) exciton dissociation, presumably by allowing the electron and hole to separate on different polymer strands. For both samples, photoexcitation leads to the predominant formation of bound charge pairs (excitons) that can be detected through their polarizability. Surprisingly, the polarizability per absorbed photon is a factor of 3 larger in solution than in the film, suggesting that interchain interactions in the film do not result in a substantial delocalization of the exciton wave function. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B (Condensed Matter and Materials Physics)
volume
71
issue
12
pages
1 - 125201
publisher
American Physical Society
external identifiers
  • wos:000228923300061
  • scopus:20144367234
ISSN
1098-0121
DOI
10.1103/PhysRevB.71.125201
language
English
LU publication?
yes
id
768aa071-dc37-4d06-9a8d-d7a453ec785d (old id 157795)
date added to LUP
2007-07-03 13:05:38
date last changed
2017-09-03 04:34:56
@article{768aa071-dc37-4d06-9a8d-d7a453ec785d,
  abstract     = {We compare the generation and decay dynamics of charges and excitons in a model polymer semiconductor (MEH-PPV) in solution and drop-cast thin films, by recording the sub-ps transient complex conductivity using THz time-domain spectroscopy. The results show that the quantum efficiency of charge generation is two orders of magnitude smaller in solution (~10–5) than in the solid film (~10–3). The proximity of neighboring chains in the films apparently facilitates (hot) exciton dissociation, presumably by allowing the electron and hole to separate on different polymer strands. For both samples, photoexcitation leads to the predominant formation of bound charge pairs (excitons) that can be detected through their polarizability. Surprisingly, the polarizability per absorbed photon is a factor of 3 larger in solution than in the film, suggesting that interchain interactions in the film do not result in a substantial delocalization of the exciton wave function.},
  author       = {Hendry, E and Koeberg, M and Schins, J M and Nienhuys, Han-Kwang and Sundström, Villy and Siebbeles, L D A and Bonn, M},
  issn         = {1098-0121},
  language     = {eng},
  number       = {12},
  pages        = {1--125201},
  publisher    = {American Physical Society},
  series       = {Physical Review B (Condensed Matter and Materials Physics)},
  title        = {Interchain effects in the ultrafast photophysics of a semiconducting polymer: THz time-domain spectroscopy of thin films and isolated chains in solution},
  url          = {http://dx.doi.org/10.1103/PhysRevB.71.125201},
  volume       = {71},
  year         = {2005},
}