Origin of Efficient Inverted Nonfullerene Organic Solar Cells: Enhancement of Charge Extraction and Suppression of Bimolecular Recombination Enabled by Augmented Internal Electric Field

Yiwen Wang, Bo Wu, Zhenghui Wu, Zhaojue Lan, Yongfang Li, Maojie Zhang*, Fu Rong ZHU

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)

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%).

Original languageEnglish
Pages (from-to)5264-5271
Number of pages8
JournalJournal of Physical Chemistry Letters
Volume8
Issue number21
DOIs
Publication statusPublished - 2 Nov 2017

Scopus Subject Areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

Fingerprint

Dive into the research topics of 'Origin of Efficient Inverted Nonfullerene Organic Solar Cells: Enhancement of Charge Extraction and Suppression of Bimolecular Recombination Enabled by Augmented Internal Electric Field'. Together they form a unique fingerprint.

Cite this