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Weihua Lin. Portrait.

Weihua Lin

Postdoctoral fellow

Weihua Lin. Portrait.

Mechanistic Investigation into Dynamic Function of Third-Component Incorporated in Ternary Near-Infrared Nonfullerene Organic Solar Cells

Author

  • Zhuoyan Wang
  • Jingjing Ji
  • Weihua Lin
  • Yao Yao
  • Kaibo Zheng
  • Ziqi Liang

Summary, in English

Organic solar cells (OSCs) consisting of an ultralow-bandgap nonfullerene acceptor (NFA) with an optical absorption edge that extends to the near-infrared (NIR) region are of vital interest to semitransparent and tandem devices. However, huge energy-loss related to inefficient charge dissociation hinders their further development. The critical issues of charge separation as exemplified in NIR-NFA OSCs based on the paradigm blend of PTB7–Th donor (D) and IEICO–4F acceptor (A) are revealed here. These studies corroborate efficient charge transfer between D and A, accompanied by geminate recombination of photo-excited charge carriers. Two key factors restricting charge separation are unveiled as the connection discontinuity of individual phases in the blend and long-lived interfacial charge-transfer states (CTS). By incorporation of a third-component of benchmark ITIC or PC71BM with various molar ratios, these two issues are well-resolved accordingly, yet in distinctly influencing mechanisms. ITIC molecules modulate film morphology to create more continuous paths for charge transportation, whereas PC71BM diminishes CTS and enhances electron transfer at the D/A interfaces. Consequently, the optimal untreated ternary OSCs comprising 0.3 wt% ITIC and 0.1 wt% PC71BM in the blend deliver higher JSC values of 21.9 and 25.4 mA cm-2, and hence increased PCE of 10.2% and 10.6%, respectively.

Department/s

  • Chemical Physics
  • NanoLund: Centre for Nanoscience

Publishing year

2020-08-03

Language

English

Publication/Series

Advanced Functional Materials

Volume

30

Issue

31

Document type

Journal article

Publisher

Wiley-Blackwell

Topic

  • Condensed Matter Physics (including Material Physics, Nano Physics)

Keywords

  • charge and energy transfer
  • charge recombination
  • near-infrared
  • nonfullerene acceptors
  • organic solar cells

Status

Published

ISBN/ISSN/Other

  • ISSN: 1616-301X