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Diketopyrrolopyrroles with a Distinct Energy Level Cascade for Efficient Charge Carrier Generation in Organic Solar Cells

Title data

Müller, Christian J. ; Brendel, Michael ; Ruckdeschel, Pia ; Pflaum, Jens ; Thelakkat, Mukundan:
Diketopyrrolopyrroles with a Distinct Energy Level Cascade for Efficient Charge Carrier Generation in Organic Solar Cells.
In: Advanced Energy Materials. Vol. 5 (2015) Issue 21 . - n/a-n/a.
ISSN 1614-6840
DOI: https://doi.org/10.1002/aenm.201500914

Official URL: Volltext

Project information

Project financing: Deutsche Forschungsgemeinschaft
Bayerisches Staatsministerium für Wissenschaft, Forschung und Kunst

Abstract in another language

Three structurally different low molecular weight diketopyrrolopyrroles (DPPs) are synthesized in order to provide donors with a precise offset in their energy levels. The DPPs are characterized for optical, electrochemical, and thermal properties. By changing the terminal aryl groups attached to the DPP core from phenyl over m-pyridine to p-pyridine, different solid state packing is observed in thin film studies using UV/VIS absorption spectra and X-ray diffraction. Most importantly it is shown that both, reduction as well as oxidation potentials can be precisely tuned with a gradual stepping of about 100 meV by changing the terminal groups attached to the DPP core. Exploiting this energy level modification, these materials are tested in planar cascade organic photovoltaic devices using C60 as acceptor. A sub nm thick interlayer of a suitable DPP derivative is introduced to obtain a distinct energy level cascade at the donor/acceptor interface. Power conversion efficiency as well as short-circuit current density is doubled with respect to the reference bilayer devices lacking the interface cascade. Spectrally resolved analysis of external quantum efficiency reveals that this enhancement can mainly be attributed to destabilization of bound charge transfer states formed in the C60 layer at the interlayer interface, thus reducing geminate recombination losses.

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: 1500914
Keywords: cascade solar cells; diketopyrrolopyrroles; interlayers; physical vapor deposition; recombination
Institutions of the University: Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Macromolecular Chemistry I
Profile Fields
Profile Fields > Advanced Fields
Profile Fields > Advanced Fields > Polymer and Colloid Science
Profile Fields > Emerging Fields
Profile Fields > Emerging Fields > Energy Research and Energy Technology
Graduate Schools
Graduate Schools > Elite Network Bavaria
Graduate Schools > Elite Network Bavaria > Macromolecular Science
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Professorship Applied Functional Polymers > Professorship Applied Functional Polymers - Univ.-Prof. Dr. Mukundan Thelakkat
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Professorship Applied Functional Polymers
Result of work at the UBT: Yes
DDC Subjects: 500 Science
500 Science > 540 Chemistry
Date Deposited: 23 Jun 2016 08:50
Last Modified: 22 Jan 2018 08:44
URI: https://eref.uni-bayreuth.de/id/eprint/32204