Journal article
The role of spin in the degradation of organic photovoltaics
- Abstract:
- Stability is now a critical factor in the commercialization of organic photovoltaic (OPV) devices. Both extrinsic stability to oxygen and water and intrinsic stability to light and heat in inert conditions must be achieved. Triplet states are known to be problematic in both cases, leading to singlet oxygen production or fullerene dimerization. The latter is thought to proceed from unquenched singlet excitons that have undergone intersystem crossing (ISC). Instead, we show that in bulk heterojunction (BHJ) solar cells the photo-degradation of C<sub>60</sub> via photo-oligomerization occurs primarily via back-hole transfer (BHT) from a charge-transfer state to a C<sub>60</sub> excited triplet state. We demonstrate this to be the principal pathway from a combination of steady-state optoelectronic measurements, time-resolved electron paramagnetic resonance, and temperature-dependent transient absorption spectroscopy on model systems. BHT is a much more serious concern than ISC because it cannot be mitigated by improved exciton quenching, obtained for example by a finer BHJ morphology. As BHT is not specific to fullerenes, our results suggest that the role of electron and hole back transfer in the degradation of BHJs should also be carefully considered when designing stable OPV devices.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, 2.0MB, Terms of use)
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- Publisher copy:
- 10.1038/s41467-020-20601-6
Authors
- Publisher:
- Springer Nature
- Journal:
- Nature Communications More from this journal
- Volume:
- 12
- Issue:
- 1
- Article number:
- 471
- Publication date:
- 2021-01-20
- Acceptance date:
- 2020-12-07
- DOI:
- EISSN:
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2041-1723
- ISSN:
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2041-1723
- Pmid:
-
33473110
- Language:
-
English
- Keywords:
- Pubs id:
-
1158522
- Local pid:
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pubs:1158522
- Deposit date:
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2021-02-10
Terms of use
- Copyright holder:
- Ramirez et al.
- Copyright date:
- 2021
- Rights statement:
- ©2021 The Authors. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
- Licence:
- CC Attribution (CC BY)
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