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Grob, S., Bartynski, A. N., Opitz, A., Gruber, M., Grassl, F., Meister, E., . . . Bruetting, W. (2015). Solvent vapor annealing on perylene-based organic solar cells. Journal of Materials Chemistry A, 3(30), 15700-15709
Open this publication in new window or tab >>Solvent vapor annealing on perylene-based organic solar cells
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2015 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, no 30, p. 15700-15709Article in journal (Refereed) Published
Abstract [en]

Diindenoperylene (DIP) and tetraphenyldibenzoperiflanthene (DBP) are two commonly used donor materials in organic solar cell devices. Despite their structural similarities, DIP films are crystalline, exhibiting good charge and exciton transport, whereas DBP films are amorphous and have lower carrier mobility and a short exciton diffusion length. However, DBP reveals a distinctly higher absorption due to the lying orientation of its transition dipole moments. In this paper, we investigate the influence of solvent vapor annealing (SVA) on the solar cell performance of both materials. In general, SVA induces a partial re-solubilization of the material leading to enhanced crystallinity of the treated layer. For DBP, extended annealing times result in a strong aggregation of the molecules, creating inhomogeneous layers unfavorable for solar cells. However, in DIP cells, SVA leads to an increase in fill factor (FF) and also a slight increase in short-circuit current density (JSC) due to interface roughening. The best results are obtained by combining solvent vapor annealed DIP layers with strongly absorbing DBP and C-70 on top. Through this device architecture, we obtain the same increase in FF in addition to a higher gain in J(SC), elevating the power conversion efficiency by a factor of 1.2 to more than 4%.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2015
National Category
Chemical Engineering
Research subject
Chemical Engineering
urn:nbn:se:kau:diva-41645 (URN)10.1039/c5ta02806j (DOI)000358211700042 ()
Available from: 2016-04-11 Created: 2016-04-11 Last updated: 2020-01-14Bibliographically approved
Hörmann, U., Lorch, C., Hinderhofer, A., Gerlach, A., Gruber, M., Kraus, J., . . . Brütting, W. (2014). Voc from a Morphology Point of View: the Influence of Molecular Orientation on the Open Circuit Voltage of Organic Planar Heterojunction Solar Cells. Journal of physical chemistry C, 118(46), 26462-26470
Open this publication in new window or tab >>Voc from a Morphology Point of View: the Influence of Molecular Orientation on the Open Circuit Voltage of Organic Planar Heterojunction Solar Cells
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2014 (English)In: Journal of physical chemistry C, ISSN 1932-7455, Vol. 118, no 46, p. 26462-26470Article in journal (Refereed) Published
Abstract [en]

The film morphology and device performance of planar heterojunction

solar cells based on the molecular donor material α-sexithiophene (6T) are investigated.

Planar heterojunctions of 6T with two different acceptor molecules, the C60 fullerene and

diindenoperylene (DIP), have been prepared. The growth temperature of the 6T bottom

layer has been varied between room temperature and 100 °C for each acceptor. By means

of X-ray diffraction and X-ray absorption, we show that the crystallinity and the molecular

orientation of 6T is influenced by the preparation conditions and that the 6T film

templates the growth of the subsequent acceptor layer. These structural changes are

accompanied by changes in the characteristic parameters of the corresponding

photovoltaic cells. This is most prominently observed as a shift of the open circuit

voltage (Voc): In the case of 6T/C60 heterojunctions, Voc decreases from 0.4 to 0.3 V,

approximately, if the growth temperature of 6T is increased from room temperature to 100

°C. By contrast, Voc increases from about 1.2 V to almost 1.4 V in the case of 6T/DIP solar

cells under the same conditions. We attribute these changes upon substrate heating to

increased recombination in the C60 case while an orientation dependent intermolecular coupling seems to change the origin of the photovoltaic gap in the DIP case.

National Category
Condensed Matter Physics
Research subject
Physics; Materials Science
urn:nbn:se:kau:diva-35420 (URN)10.1021/jp506180k (DOI)000345474000005 ()
German Research Foundation (DFG), SPP 1355Göran Gustafsson Foundation for Research in Natural Sciences and Medicine

publication date: October 27, 2014

Available from: 2015-03-22 Created: 2015-03-22 Last updated: 2018-06-20Bibliographically approved

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