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URN to cite this document: urn:nbn:de:bvb:703-epub-6678-6
Title data
Hochgesang, Adrian ; Biberger, Simon ; Grüne, Jeannine ; Mohanraj, John ; Kahle, Frank-Julian ; Dyakonov, Vladimir ; Köhler, Anna ; Thelakkat, Mukundan:
Intricacies and Mechanism of p-Doping Spiro-MeOTAD Using Cu(TFSI)₂.
In: Advanced Electronic Materials.
Vol. 8
(2022)
Issue 10
.
- No. 2200113.
ISSN 2199-160X
DOI der Verlagsversion: https://doi.org/10.1002/aelm.202200113
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Abstract
Abstract Copper salts are a popular choice as p-dopants for organic semiconductors, particularly in N2,N2,N2′,N2′,N7,N7,N7′,N7′-octakis(4-methoxyphenyl)-9,9′-spirobi9H-fluoren-2,2′,7,7′-tetramine (Spiro-MeOTAD) hole transport material for solar cells. While being exceptionally effective, no scientific consensus about their doping mechanism has been established so far. This study describes the thermodynamic equilibria of involved species in copper(II) bis(trifluoromethanesulfonyl)imide (Cu(TFSI)2) doped, co-evaporated Spiro-MeOTAD. A temperature-independent formation of charge transfer states is found, followed by an endothermic release of free charge carriers. Impedance and electron paramagnetic resonance spectroscopy unravel low activation energies for hole release and hopping transport. As a result, (52.0 ± 6.4)\% of the total Cu(TFSI)2 molecules form free, dissociated holes at 10 mol\% and room temperature. CuI species arising out of doping are stabilized by formation of a CuI(TFSI)2- cuprate, inhibiting elemental copper formation. This CuI species presents a potent hole trap reducing their mobility, which can be averted by simple addition of a bathocuproine complexing agent. A nonlinear temperature-dependent conductivity and mobility that contradicts current charge transport models is observed. This is attributed to a combination of trap- and charge transfer state freeze-out. These insights may be adapted to other metal salts, providing guidelines for designing next-generation ultra-high efficiency dopants.
Further data
| Item Type: | Article in a journal |
|---|---|
| Keywords: | copper; doping; electron transfer; reaction mechanisms; semiconductors |
| DDC Subjects: | 500 Science > 530 Physics |
| Institutions of the University: | Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics II - Optoelectronics of Soft Matter Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics II - Optoelectronics of Soft Matter > Chair Experimental Physics II - Optoelectronics of Soft Matter - Univ.-Prof. Dr. Anna Köhler Faculties Faculties > Faculty of Mathematics, Physics und Computer Science |
| Language: | English |
| Originates at UBT: | Yes |
| URN: | urn:nbn:de:bvb:703-epub-6678-6 |
| Date Deposited: | 29 Sep 2022 08:45 |
| Last Modified: | 13 Oct 2022 07:49 |
| URI: | https://epub.uni-bayreuth.de/id/eprint/6678 |
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