18.73% efficient and stable inverted organic photovoltaics featuring a hybrid hole-extraction layer
Journal article, 2023
Developing efficient and stable organic photovoltaics (OPVs) is crucial for the technology's commercial success. However, combining these key attributes remains challenging. Herein, we incorporate the small molecule 2-((3,6-dibromo-9H-carbazol-9-yl)ethyl)phosphonic acid (Br-2PACz) between the bulk-heterojunction (BHJ) and a 7 nm-thin layer of MoO3 in inverted OPVs, and study its effects on the cell performance. We find that the Br-2PACz/MoO3 hole-extraction layer (HEL) boosts the cell's power conversion efficiency (PCE) from 17.36% to 18.73% (uncertified), making them the most efficient inverted OPVs to date. The factors responsible for this improvement include enhanced charge transport, reduced carrier recombination, and favourable vertical phase separation of donor and acceptor components in the BHJ. The Br-2PACz/MoO3-based OPVs exhibit higher operational stability under continuous illumination and thermal annealing (80 degrees C). The T-80 lifetime of OPVs featuring Br-2PACz/MoO3 - taken as the time over which the cell's PCE reduces to 80% of its initial value - increases compared to MoO3-only cells from 297 to 615 h upon illumination and from 731 to 1064 h upon continuous heating. Elemental analysis of the BHJs reveals the enhanced stability to originate from the partially suppressed diffusion of Mo ions into the BHJ and the favourable distribution of the donor and acceptor components induced by the Br-2PACz.
Author
Yuanbao Lin
University of Oxford
King Abdullah University of Science and Technology (KAUST)
Yadong Zhang
University of Colorado
University of Colorado at Boulder
Artiom Magomedov
Kaunas University of Technology
Eleftheria Gkogkosi
National Technical University of Athens (NTUA)
Junxiang Zhang
University of Colorado at Boulder
University of Colorado
Xiaopeng Zheng
King Abdullah University of Science and Technology (KAUST)
Abdulrahman El-Labban
King Abdullah University of Science and Technology (KAUST)
Stephen Barlow
University of Colorado at Boulder
University of Colorado
Vytautas Getautis
Kaunas University of Technology
Ergang Wang
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Leonidas Tsetseris
National Technical University of Athens (NTUA)
Seth R. Marder
University of Colorado at Boulder
University of Colorado
Iain McCulloch
University of Oxford
Thomas D. D. Anthopoulos
King Abdullah University of Science and Technology (KAUST)
Materials Horizons
2051-6347 (ISSN) 2051-6355 (eISSN)
Vol. 10 4 1292-1300Subject Categories
Other Chemical Engineering
Other Chemistry Topics
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
DOI
10.1039/d2mh01575g
PubMed
36786547