Document Type

Journal Article

Department/Unit

Department of Physics

Language

English

Abstract

We report our effort to unravel the origin of efficient operation of nonfullerene organic solar cells (OSCs), based on a poly[4,8-bis(5-(2-ethylhexyl) thiophen-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)](PTB7-Th):3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno [1,2-b:5,6-b′]dithiophene (ITIC) blend system. The effects of buildup of space charges, charge extraction, and bimolecular recombination processes on the performance and the stability of PTB7-Th:ITIC-based regular and reverse configuration OSCs are analyzed. It is found that the high-performing inverted PTB7-Th:ITIC OSCs benefit from the combined effects of (1) suppression of bimolecular recombination enabled by an augmented effective internal electric field and (2) improvement of charge extraction by avoiding the holes passing through ITIC-rich region, which would otherwise occur in a regular configuration cell. The inverted PTB7-Th:ITIC OSCs possess a significant improvement in the cell stability and a high power conversion efficiency of ∼8.0%, which is > 29% higher than that of an optimized regular configuration control cell (6.1%).

Publication Date

11-2017

Source Publication Title

Journal of Physical Chemistry Letters

Volume

8

Issue

21

Start Page

5264

End Page

5271

Publisher

American Chemical Society

Peer Reviewed

1

Copyright

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/acs.jpclett.7b02308

Funder

This work was financially supported by the Research Grants Council of Hong Kong Special Administrative Region, China; General Research Fund (12303114, 12302817); Hong Kong Baptist University Interinstitutional Collaborative Research Scheme (RC-ICRS/15-16/04); and Shenzhen Peacock Plan (KQTD20140630110339343).

DOI

10.1021/acs.jpclett.7b02308

Link to Publisher's Edition

http://dx.doi.org/10.1021/acs.jpclett.7b02308

ISSN (electronic)

19487185

JA-5052-29419_suppl.pdf (516 kB)
Supporting Information

Available for download on Saturday, December 01, 2018

Additional Files

JA-5052-29419_suppl.pdf (516 kB)
Supporting Information

Included in

Physics Commons

Share

COinS