Polarons in Narrow Band Gap Polymers Probed over the Entire Infrared Range: A Joint Experimental and Theoretical Investigation

Beitrag in einer Fachzeitschrift
(Originalarbeit)


Details zur Publikation

Autor(en): Kahmann S, Fazzi D, Matt G, Thiel W, Loi MA, Brabec C
Zeitschrift: Journal of Physical Chemistry Letters
Verlag: American Chemical Society
Jahr der Veröffentlichung: 2016
Band: 7
Heftnummer: 22
Seitenbereich: 4438-4444
ISSN: 1948-7185
Sprache: Englisch


Abstract


We investigate the photoinduced absorption (PIA) spectra of the prototypical donor-acceptor polymer [2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (C-PCPDTBT) and its silicon bridged variant Si-PCPDTBT over a spectral range from 0.07 to 1.5 eV. Comparison between time-dependent density functional theory simulations of the electronic and vibrational transitions of singlet excitons, triplet excitons, polarons, and bipolarons with the experimental results proves that the observed features are due to positive polarons delocalized on the polymer chains. We find that the more crystalline Si-bridged variant gives rise to a red-shift in the transition energies, especially in the mid-infrared (MIR) spectral range and furthermore observe that the pristine polymers' responses depend on the excitation energy. Blending with PCBM, on the other hand, leads to excitation-independent PIA spectra. By computing the response properties of molecular aggregates, we show that polarons are delocalized in not only the intra- but also the interchain direction, leading to intermolecular transitions which correspond well to experimental absorption features at the lowest energies.



FAU-Autoren / FAU-Herausgeber

Brabec, Christoph Prof. Dr.
Lehrstuhl für Werkstoffwissenschaften (Materialien der Elektronik und der Energietechnologie)
Kahmann, Simon
Lehrstuhl für Werkstoffwissenschaften (Materialien der Elektronik und der Energietechnologie)
Matt, Gebhard Dr.
Lehrstuhl für Werkstoffwissenschaften (Materialien der Elektronik und der Energietechnologie)


Zusätzliche Organisationseinheit(en)
Graduiertenkolleg 1896/2 In situ Mikroskopie mit Elektronen, Röntgenstrahlen und Rastersonden
Interdisziplinäres Zentrum, Center for Nanoanalysis and Electron Microscopy (CENEM)


Autor(en) der externen Einrichtung(en)
Max-Planck-Institut für Kohlenforschung (MPI KoFo) / Max Planck Institute for Coal Research
University of Groningen / Rijksuniversiteit Groningen


Zitierweisen

APA:
Kahmann, S., Fazzi, D., Matt, G., Thiel, W., Loi, M.A., & Brabec, C. (2016). Polarons in Narrow Band Gap Polymers Probed over the Entire Infrared Range: A Joint Experimental and Theoretical Investigation. Journal of Physical Chemistry Letters, 7(22), 4438-4444. https://dx.doi.org/10.1021/acs.jpclett.6b02083

MLA:
Kahmann, Simon, et al. "Polarons in Narrow Band Gap Polymers Probed over the Entire Infrared Range: A Joint Experimental and Theoretical Investigation." Journal of Physical Chemistry Letters 7.22 (2016): 4438-4444.

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Zuletzt aktualisiert 2019-03-06 um 16:28