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Hahn, Tobias ; Tscheuschner, Steffen ; Saller, Christina ; Strohriegl, Peter ; Boregowda, Puttarraju ; Mukhopadhyay, Tushita ; Patil, Satish ; Neher, Dieter ; Bässler, Heinz ; Köhler, Anna:
Role of Intrinsic Photogeneration in Single Layer and Bilayer Solar Cells with C60 and PCBM.
In: The Journal of Physical Chemistry C.
Bd. 120
(2016)
Heft 43
.
- S. 25083-25091.
ISSN 1932-7455
DOI: https://doi.org/10.1021/acs.jpcc.6b08471
Abstract
In an endeavor to examine how optical excitation of C60 and PCBM contribute to the photogeneration of charge carriers in organic solar cells, we investigated stationary photogeneration in single-layer C60 and PCBM films over a broad spectrum as a function of the electric field. We find that intrinsic photogeneration starts at a photon energy of about 2.25 eV, i.e., about 0.4 eV above the first singlet excited state. It originates from charge transfer type states that can autoionize before relaxing to the lower-energy singlet S1 state, in the spirit of Onsager’s 1938 theory. We analyze the internal quantum efficiency as a function of electric field and photon energy to determine (1) the Coulombic binding and separation of the electron–hole pairs, (2) the value of the electrical gap, and (3) which fraction of photoexcitations can fully separate at a given photon energy. The latter depends on the coupling between the photogenerated charge transfer states and the eventual charge transporting states. It is by a factor of 3 lower in PCBM. Close to the threshold energy for intrinsic photoconduction (2.25 eV), the generating entity is a photogenerated electron–hole pair with roughly 2 nm separation. At higher photon energy, more expanded pairs are produced incoherently via thermalization.
Weitere Angaben
| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Institutionen der Universität: | Fakultäten > Fakultät für Mathematik, Physik und Informatik > Physikalisches Institut > Lehrstuhl Experimentalphysik II - Optoelektronik weicher Materie > Lehrstuhl Experimentalphysik II - Optoelektronik weicher Materie - Univ.-Prof. Dr. Anna Köhler Fakultäten Fakultäten > Fakultät für Mathematik, Physik und Informatik Fakultäten > Fakultät für Mathematik, Physik und Informatik > Physikalisches Institut Fakultäten > Fakultät für Mathematik, Physik und Informatik > Physikalisches Institut > Lehrstuhl Experimentalphysik II - Optoelektronik weicher Materie |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 530 Physik |
| Eingestellt am: | 07 Dec 2016 12:19 |
| Letzte Änderung: | 07 Dec 2016 12:19 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/35405 |