The role of charge recombination to triplet excitons in organic solar cells

Alexander J. Gillett (), Alberto Privitera, Rishat Dilmurat, Akchheta Karki, Deping Qian, Anton Pershin, Giacomo Londi, William K. Myers, Jaewon Lee, Jun Yuan, Seo-Jin Ko, Moritz K. Riede, Feng Gao, Guillermo C. Bazan, Akshay Rao, Thuc-Quyen Nguyen (), David Beljonne () and Richard H. Friend ()
Additional contact information
Alexander J. Gillett: University of Cambridge
Alberto Privitera: University of Oxford
Rishat Dilmurat: Université de Mons
Akchheta Karki: University of California at Santa Barbara
Deping Qian: Linköping University
Anton Pershin: Université de Mons
Giacomo Londi: Université de Mons
William K. Myers: University of Oxford
Jaewon Lee: University of California at Santa Barbara
Jun Yuan: Linköping University
Seo-Jin Ko: University of California at Santa Barbara
Moritz K. Riede: University of Oxford
Feng Gao: Linköping University
Guillermo C. Bazan: University of California at Santa Barbara
Akshay Rao: University of Cambridge
Thuc-Quyen Nguyen: University of California at Santa Barbara
David Beljonne: Université de Mons
Richard H. Friend: University of Cambridge

Nature, 2021, vol. 597, issue 7878, 666-671

Abstract: Abstract The use of non-fullerene acceptors (NFAs) in organic solar cells has led to power conversion efficiencies as high as 18%1. However, organic solar cells are still less efficient than inorganic solar cells, which typically have power conversion efficiencies of more than 20%2. A key reason for this difference is that organic solar cells have low open-circuit voltages relative to their optical bandgaps3, owing to non-radiative recombination4. For organic solar cells to compete with inorganic solar cells in terms of efficiency, non-radiative loss pathways must be identified and suppressed. Here we show that in most organic solar cells that use NFAs, the majority of charge recombination under open-circuit conditions proceeds via the formation of non-emissive NFA triplet excitons; in the benchmark PM6:Y6 blend5, this fraction reaches 90%, reducing the open-circuit voltage by 60 mV. We prevent recombination via this non-radiative channel by engineering substantial hybridization between the NFA triplet excitons and the spin-triplet charge-transfer excitons. Modelling suggests that the rate of back charge transfer from spin-triplet charge-transfer excitons to molecular triplet excitons may be reduced by an order of magnitude, enabling re-dissociation of the spin-triplet charge-transfer exciton. We demonstrate NFA systems in which the formation of triplet excitons is suppressed. This work thus provides a design pathway for organic solar cells with power conversion efficiencies of 20% or more.

Date: 2021
References: Add references at CitEc
Citations: View citations in EconPapers (19)

Downloads: (external link)
https://www.nature.com/articles/s41586-021-03840-5 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:597:y:2021:i:7878:d:10.1038_s41586-021-03840-5

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-021-03840-5

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().