Altmetric

Fine-Tuning the Energy Levels of a Nonfullerene Small-Molecule Acceptor to Achieve a High Short-Circuit Current and a Power Conversion Efficiency over 12% in Organic Solar Cells.

File Description SizeFormat 
AM-2017-MS-V11-pdf-deposit.pdfAccepted version1.18 MBAdobe PDFView/Open
Title: Fine-Tuning the Energy Levels of a Nonfullerene Small-Molecule Acceptor to Achieve a High Short-Circuit Current and a Power Conversion Efficiency over 12% in Organic Solar Cells.
Authors: Kan, B
Zhang, J
Liu, F
Wan, X
Li, C
Ke, X
Wang, Y
Feng, H
Zhang, Y
Long, G
Friend, RH
Bakulin, AA
Chen, Y
Item Type: Journal Article
Abstract: Organic solar cell optimization requires careful balancing of current-voltage output of the materials system. Here, such optimization using ultrafast spectroscopy as a tool to optimize the material bandgap without altering ultrafast photophysics is reported. A new acceptor-donor-acceptor (A-D-A)-type small-molecule acceptor NCBDT is designed by modification of the D and A units of NFBDT. Compared to NFBDT, NCBDT exhibits upshifted highest occupied molecular orbital (HOMO) energy level mainly due to the additional octyl on the D unit and downshifted lowest unoccupied molecular orbital (LUMO) energy level due to the fluorination of A units. NCBDT has a low optical bandgap of 1.45 eV which extends the absorption range toward near-IR region, down to ≈860 nm. However, the 60 meV lowered LUMO level of NCBDT hardly changes the Voc level, and the elevation of the NCBDT HOMO does not have a substantial influence on the photophysics of the materials. Thus, for both NCBDT- and NFBDT-based systems, an unusually slow (≈400 ps) but ultimately efficient charge generation mediated by interfacial charge-pair states is observed, followed by effective charge extraction. As a result, the PBDB-T:NCBDT devices demonstrate an impressive power conversion efficiency over 12%-among the best for solution-processed organic solar cells.
Issue Date: 4-Dec-2017
Date of Acceptance: 23-Oct-2017
URI: http://hdl.handle.net/10044/1/54983
DOI: https://dx.doi.org/10.1002/adma.201704904
ISSN: 0935-9648
Publisher: Wiley
Journal / Book Title: Advanced Materials
Volume: 30
Issue: 3
Copyright Statement: This is the peer reviewed version of the following article: B. Kan, J. Zhang, F. Liu, X. Wan, C. Li, X. Ke, Y. Wang, H. Feng, Y. Zhang, G. Long, R. H. Friend, A. A. Bakulin, Y. Chen, Adv. Mater. 2017, 1704904, which has been published in final form at https://dx.doi.org/10.1002/adma.201704904. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
Sponsor/Funder: The Royal Society
Funder's Grant Number: UF130178
Keywords: charge separation
high-performance organic solar cells
low bandgap
small-molecule nonfullerene acceptors
charge separation
high-performance organic solar cells
low bandgap
small-molecule nonfullerene acceptors
02 Physical Sciences
03 Chemical Sciences
09 Engineering
Nanoscience & Nanotechnology
Publication Status: Published online
Article Number: 1704904
Appears in Collections:Chemistry
Faculty of Natural Sciences



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Creative Commonsx