Over 16.7% efficiency of ternary organic photovoltaics by employing extra PC71BM as morphology regulator

Jinhua Gao, Jian Wang, Qiaoshi An, Xiaoling Ma, Zhenghao Hu, Chunyu Xu, Xiaoli Zhang, Fujun Zhang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

166 Citations (Scopus)

Abstract

Ternary organic photovoltaics (OPVs) are fabricated with PBDB-T-2Cl:Y6 (1:1.2, wt/wt) as the host system and extra PC71BM as the third component. The PBDB-T-2Cl:Y6 based binary OPVs exhibit a power conversion efficiency (PCE) of 15.49% with a short circuit current (JSC) of 24.98 mA cm−2, an open circuit voltage (VOC) of 0.868 V and a fill factor (FF) of 71.42%. A 16.71% PCE is obtained in the optimized ternary OPVs with PBDB-T-2Cl:Y6:PC71BM (1:1.2:0.2, wt/wt) active layer, resulting from the synchronously improved JSC of 25.44 mA cm−2, FF of 75.66% and the constant VOC of 0.868 V. The incorporated PC71BM may prefer to mix with Y6 to finely adjust phase separation, domain size and molecular arrangement in ternary active layers, which can be confirmed from the characterization on morphology, 2D grazing incidence small and wide-angle X-ray scattering, as well as Raman mapping. In addition, PC71BM may prefer to mix with Y6 to form efficient electron transport channels, which should be conducive to charge transport and collection in the optimized ternary OPVs. This work provides more insight into the underlying reasons of the third component on performance improvement of ternary OPVs, indicating ternary strategy should be an efficient method to optimize active layers for synchronously improving photon harvesting, exciton dissociation and charge transport, while keeping the simple cell fabrication technology.

Original languageEnglish
Pages (from-to)83-91
Number of pages9
JournalScience China Chemistry
Volume63
Issue number1
DOIs
Publication statusPublished - 1 Jan 2020
Externally publishedYes

Keywords

  • morphology regulator
  • organic photovoltaics
  • organic solar cells
  • power conversion efficiency
  • ternary strategy

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