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Photo-Oxidation Reveals H-Aggregates Hidden in Spin-Cast-Conjugated Polymer Films as Observed by Two-Dimensional Polarization Imaging

Shi, Juanzi LU ; Xu, Xiaofeng ; Xia, Yuxin ; Chen, Ruiyun LU ; Hawash, Zafer ; Deribew, Dargie ; Moons, Ellen ; Inganäs, Olle and Scheblykin, Ivan G. LU (2019) In Chemistry of Materials p.8927-8936
Abstract

Spin-cast intermolecular interactions in conjugated polymer films lead to the formation of excited states delocalized over a few oriented and tightly packed conjugated segments. The optoelectronic properties of conjugated polymers are strongly dependent on the presence of such oriented domains at a nanoscale level. We observe oriented domains as large as several micrometers in size spontaneously formed in spin-cast PBDT-TPD films. Two-dimensional polarization imaging of fresh and photodegraded films showed a much higher visibility of the oriented domains in the degraded samples. We propose that the film is a mixture of two phases with different degrees of chain alignment. The photoluminescence of the more anisotropic phase is more... (More)

Spin-cast intermolecular interactions in conjugated polymer films lead to the formation of excited states delocalized over a few oriented and tightly packed conjugated segments. The optoelectronic properties of conjugated polymers are strongly dependent on the presence of such oriented domains at a nanoscale level. We observe oriented domains as large as several micrometers in size spontaneously formed in spin-cast PBDT-TPD films. Two-dimensional polarization imaging of fresh and photodegraded films showed a much higher visibility of the oriented domains in the degraded samples. We propose that the film is a mixture of two phases with different degrees of chain alignment. The photoluminescence of the more anisotropic phase is more stable against photodegradation in comparison with the less anisotropic phase. Photodegradation predominately quenches photoluminescence of the less anisotropic phase making the oriented domains more visible in the polarization contrasts. Spectral and energy transfer properties of the more oriented phase allowed us to assign it to weakly coupled H-aggregates with the suppressed 0-0 vibronic transition. Stable photoluminescence of H-aggregates in comparison with that of nonaggregated (less oriented) chains may help to understand degradation mechanisms of polymer devices and shows the role of energy transfer in this process. Selective degradation-induced quenching can reveal hidden inhomogeneity of conjugated polymer films.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Chemistry of Materials
pages
8927 - 8936
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85074566785
ISSN
0897-4756
DOI
10.1021/acs.chemmater.9b02996
language
English
LU publication?
yes
id
0a6e4a24-7349-4aed-952d-fcc6a0a215aa
date added to LUP
2019-11-25 14:00:22
date last changed
2020-01-13 02:32:48
@article{0a6e4a24-7349-4aed-952d-fcc6a0a215aa,
  abstract     = {<p>Spin-cast intermolecular interactions in conjugated polymer films lead to the formation of excited states delocalized over a few oriented and tightly packed conjugated segments. The optoelectronic properties of conjugated polymers are strongly dependent on the presence of such oriented domains at a nanoscale level. We observe oriented domains as large as several micrometers in size spontaneously formed in spin-cast PBDT-TPD films. Two-dimensional polarization imaging of fresh and photodegraded films showed a much higher visibility of the oriented domains in the degraded samples. We propose that the film is a mixture of two phases with different degrees of chain alignment. The photoluminescence of the more anisotropic phase is more stable against photodegradation in comparison with the less anisotropic phase. Photodegradation predominately quenches photoluminescence of the less anisotropic phase making the oriented domains more visible in the polarization contrasts. Spectral and energy transfer properties of the more oriented phase allowed us to assign it to weakly coupled H-aggregates with the suppressed 0-0 vibronic transition. Stable photoluminescence of H-aggregates in comparison with that of nonaggregated (less oriented) chains may help to understand degradation mechanisms of polymer devices and shows the role of energy transfer in this process. Selective degradation-induced quenching can reveal hidden inhomogeneity of conjugated polymer films.</p>},
  author       = {Shi, Juanzi and Xu, Xiaofeng and Xia, Yuxin and Chen, Ruiyun and Hawash, Zafer and Deribew, Dargie and Moons, Ellen and Inganäs, Olle and Scheblykin, Ivan G.},
  issn         = {0897-4756},
  language     = {eng},
  pages        = {8927--8936},
  publisher    = {The American Chemical Society (ACS)},
  series       = {Chemistry of Materials},
  title        = {Photo-Oxidation Reveals H-Aggregates Hidden in Spin-Cast-Conjugated Polymer Films as Observed by Two-Dimensional Polarization Imaging},
  url          = {http://dx.doi.org/10.1021/acs.chemmater.9b02996},
  doi          = {10.1021/acs.chemmater.9b02996},
  year         = {2019},
}