Absence of Charge Transfer State Enables Very Low V-OC Losses in SWCNT:Fullerene Solar Cells

Journal article


Publication Details

Author(s): Classen A, Einsiedler L, Heumuelier T, Graf A, Brohmann M, Berger F, Kahmann S, Richter M, Matt GJ, Forberich K, Zaumseil J, Brabec C
Journal: Advanced Energy Materials
Publisher: WILEY-V C H VERLAG GMBH
Publication year: 2019
Volume: 9
Journal issue: 1
ISSN: 1614-6832
eISSN: 1614-6840
Language: English


Abstract

Current state-of-the-art organic solar cells (OSCs) still suffer from high losses of open-circuit voltage (V-OC). Conventional polymer:fullerene solar cells usually exhibit bandgap to V-OC losses greater than 0.8 V. Here a detailed investigation of V-OC is presented for solution-processed OSCs based on (6,5) single-walled carbon nanotube (SWCNT): [6,6]-phenyl-C-71-butyric acid methyl ester active layers. Considering the very small optical bandgap of only 1.22 eV of (6,5) SWCNTs, a high V-OC of 0.59 V leading to a low E-gap/q - V-OC = 0.63 V loss is observed. The low voltage losses are partly due to the lack of a measurable charge transfer state and partly due to the narrow absorption edge of SWCNTs. Consequently, V-OC losses attributed to a broadening of the band edge are very small, resulting in V-OC,V-SQ - V-OC,V-rad = 0.12 V. Interestingly, this loss is mainly caused by minor amounts of SWCNTs with smaller bandgaps as well as (6,5) SWCNT trions, all of which are experimentally well resolved employing Fourier transform photocurrent spectroscopy. In addition, the low losses due to band edge broadening, a very low voltage loss are also found due to nonradiative recombination, Delta V-OC,V-nonrad = 0.26 V, which is exceptional for fullerene-based OSCs.


FAU Authors / FAU Editors

Brabec, Christoph Prof. Dr.
Institute Materials for Electronics and Energy Technology (i-MEET)
Classen, Andrej
Institute Materials for Electronics and Energy Technology (i-MEET)
Einsiedler, Lukas
Institute Materials for Electronics and Energy Technology (i-MEET)
Forberich, Karen Dr.
Institute Materials for Electronics and Energy Technology (i-MEET)
Kahmann, Simon
Institute Materials for Electronics and Energy Technology (i-MEET)
Richter, Moses
Institute Materials for Electronics and Energy Technology (i-MEET)


External institutions with authors

Ruprecht-Karls-Universität Heidelberg


Research Fields

Neue Materialien und Prozesse
Research focus area of a faculty: Technische Fakultät


How to cite

APA:
Classen, A., Einsiedler, L., Heumuelier, T., Graf, A., Brohmann, M., Berger, F.,... Brabec, C. (2019). Absence of Charge Transfer State Enables Very Low V-OC Losses in SWCNT:Fullerene Solar Cells. Advanced Energy Materials, 9(1). https://dx.doi.org/10.1002/aenm.201801913

MLA:
Classen, Andrej, et al. "Absence of Charge Transfer State Enables Very Low V-OC Losses in SWCNT:Fullerene Solar Cells." Advanced Energy Materials 9.1 (2019).

BibTeX: 

Last updated on 2019-18-07 at 07:26