Abstract
Using subpicosecond transient absorption spectroscopy, we have investigated the primary photoexcitations in thin films and solutions of several phenylene-based conjugated polymers and an oligomer. We identify two features in the transient absorption spectra and dynamics that are common to all of the materials which we have studied from this family. The first spectral feature is a photoinduced absorption (PA) band peaking near 1 eV which has intensity-dependent dynamics which match the stimulated emission dynamics exactly over two orders of magnitude in excitation density. This band is associated with singlet intrachain excitons. The second spectral feature (observed only in thin films and aggregated solutions) is a PA band peaking near 1.8 eV, which is longer-lived than the 1 eV exciton PA band, and which has dynamics that are independent (or weakly-dependent) on excitation density. This feature is attributed to charge separated (interchain) excitations. These excitations are generated through a bimolecular process. By comparing to samples in which charged excitations are created deliberately by doping with C6O, we assign these secondary species as bound polarons.
| Original language | English |
|---|---|
| Title of host publication | Proceedings of SPIE - The International Society for Optical Engineering |
| Publisher | Society of Photo-Optical Instrumentation Engineers |
| Pages | 17-25 |
| Number of pages | 9 |
| Volume | 3797 |
| Publication status | Published - 1999 |
| Event | Proceedings of the 1999 Organic Light-Emitting Materials and Devices III - Denver, CO, USA Duration: Jul 19 1999 → Jul 21 1999 |
Other
| Other | Proceedings of the 1999 Organic Light-Emitting Materials and Devices III |
|---|---|
| City | Denver, CO, USA |
| Period | 7/19/99 → 7/21/99 |
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ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Condensed Matter Physics
Cite this
Universal ultrafast signatures of photoexcitations in conjugated polymers : Excitons and charge-transfer polarons. / McBranch, D. W.; Kraabel, B.; Xu, S.; Wang, H. L.; Klimov, Victor I.
Proceedings of SPIE - The International Society for Optical Engineering. Vol. 3797 Society of Photo-Optical Instrumentation Engineers, 1999. p. 17-25.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Universal ultrafast signatures of photoexcitations in conjugated polymers
T2 - Excitons and charge-transfer polarons
AU - McBranch, D. W.
AU - Kraabel, B.
AU - Xu, S.
AU - Wang, H. L.
AU - Klimov, Victor I
PY - 1999
Y1 - 1999
N2 - Using subpicosecond transient absorption spectroscopy, we have investigated the primary photoexcitations in thin films and solutions of several phenylene-based conjugated polymers and an oligomer. We identify two features in the transient absorption spectra and dynamics that are common to all of the materials which we have studied from this family. The first spectral feature is a photoinduced absorption (PA) band peaking near 1 eV which has intensity-dependent dynamics which match the stimulated emission dynamics exactly over two orders of magnitude in excitation density. This band is associated with singlet intrachain excitons. The second spectral feature (observed only in thin films and aggregated solutions) is a PA band peaking near 1.8 eV, which is longer-lived than the 1 eV exciton PA band, and which has dynamics that are independent (or weakly-dependent) on excitation density. This feature is attributed to charge separated (interchain) excitations. These excitations are generated through a bimolecular process. By comparing to samples in which charged excitations are created deliberately by doping with C6O, we assign these secondary species as bound polarons.
AB - Using subpicosecond transient absorption spectroscopy, we have investigated the primary photoexcitations in thin films and solutions of several phenylene-based conjugated polymers and an oligomer. We identify two features in the transient absorption spectra and dynamics that are common to all of the materials which we have studied from this family. The first spectral feature is a photoinduced absorption (PA) band peaking near 1 eV which has intensity-dependent dynamics which match the stimulated emission dynamics exactly over two orders of magnitude in excitation density. This band is associated with singlet intrachain excitons. The second spectral feature (observed only in thin films and aggregated solutions) is a PA band peaking near 1.8 eV, which is longer-lived than the 1 eV exciton PA band, and which has dynamics that are independent (or weakly-dependent) on excitation density. This feature is attributed to charge separated (interchain) excitations. These excitations are generated through a bimolecular process. By comparing to samples in which charged excitations are created deliberately by doping with C6O, we assign these secondary species as bound polarons.
UR - http://www.scopus.com/inward/record.url?scp=0033339291&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033339291&partnerID=8YFLogxK
M3 - Conference contribution
VL - 3797
SP - 17
EP - 25
BT - Proceedings of SPIE - The International Society for Optical Engineering
PB - Society of Photo-Optical Instrumentation Engineers
ER -