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Polarization Imaging of Emissive Charge Transfer States in Polymer/Fullerene Blends

Camacho Dejay, Rafael LU ; Meyer, Matthias LU ; Vandewal, Koen; Tang, Zheng; Inganas, Olle and Scheblykin, Ivan LU (2014) In Chemistry of Materials 26(23). p.6695-6704
Abstract
Photoexcitation of conjugated polymerfullerene blends results in population of a local charge transfer (CT) state at the interface between the two materials. The competition between recombination and dissociation of this interfacial state limits the generation of fully separated free charges. Therefore, a detailed understanding of the CT states is critical for building a comprehensive picture of the organic solar cells operation. We applied a new fluorescence microscopy method called two-dimensional polarization imaging to gain insight into the orientation of the transition dipole moments of the CT states, and the associated excitation energy transfer processes in TQ1:PCBM blend films. The polymer phase was oriented mechanically to relate... (More)
Photoexcitation of conjugated polymerfullerene blends results in population of a local charge transfer (CT) state at the interface between the two materials. The competition between recombination and dissociation of this interfacial state limits the generation of fully separated free charges. Therefore, a detailed understanding of the CT states is critical for building a comprehensive picture of the organic solar cells operation. We applied a new fluorescence microscopy method called two-dimensional polarization imaging to gain insight into the orientation of the transition dipole moments of the CT states, and the associated excitation energy transfer processes in TQ1:PCBM blend films. The polymer phase was oriented mechanically to relate the polymer dipole moment orientation to that of the CT states. CT state formation was observed to be much faster than energy transfer in the polymer phase. However, after being formed an emissive CT state does not exchange excitation energy with other CT states, suggesting that they are spatially and/or energetically isolated. We found that the quantum yield of the CT emission is smaller for CT states spatially located in the highly oriented polymer domains, which is interpreted as the result of enhanced CT state dissociation in highly ordered structures. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Chemistry of Materials
volume
26
issue
23
pages
6695 - 6704
publisher
The American Chemical Society
external identifiers
  • wos:000346326300005
  • scopus:84916623169
ISSN
0897-4756
DOI
10.1021/cm502503f
language
English
LU publication?
yes
id
dd8650f9-4c54-498b-9d9d-3a9b2bd04d5e (old id 4944577)
date added to LUP
2015-01-28 11:38:16
date last changed
2017-10-22 03:01:25
@article{dd8650f9-4c54-498b-9d9d-3a9b2bd04d5e,
  abstract     = {Photoexcitation of conjugated polymerfullerene blends results in population of a local charge transfer (CT) state at the interface between the two materials. The competition between recombination and dissociation of this interfacial state limits the generation of fully separated free charges. Therefore, a detailed understanding of the CT states is critical for building a comprehensive picture of the organic solar cells operation. We applied a new fluorescence microscopy method called two-dimensional polarization imaging to gain insight into the orientation of the transition dipole moments of the CT states, and the associated excitation energy transfer processes in TQ1:PCBM blend films. The polymer phase was oriented mechanically to relate the polymer dipole moment orientation to that of the CT states. CT state formation was observed to be much faster than energy transfer in the polymer phase. However, after being formed an emissive CT state does not exchange excitation energy with other CT states, suggesting that they are spatially and/or energetically isolated. We found that the quantum yield of the CT emission is smaller for CT states spatially located in the highly oriented polymer domains, which is interpreted as the result of enhanced CT state dissociation in highly ordered structures.},
  author       = {Camacho Dejay, Rafael and Meyer, Matthias and Vandewal, Koen and Tang, Zheng and Inganas, Olle and Scheblykin, Ivan},
  issn         = {0897-4756},
  language     = {eng},
  number       = {23},
  pages        = {6695--6704},
  publisher    = {The American Chemical Society},
  series       = {Chemistry of Materials},
  title        = {Polarization Imaging of Emissive Charge Transfer States in Polymer/Fullerene Blends},
  url          = {http://dx.doi.org/10.1021/cm502503f},
  volume       = {26},
  year         = {2014},
}