Fused-ring induced end-on orientation in conjugated molecular dyads toward efficient single-component organic solar cells

Dongdong Xia, Shengxi Zhou, Wen Liang Tan, Safakath Karuthedath, Chengyi Xiao, Chaowei Zhao, Frédéric Laquai, Christopher R. McNeill, Weiwei Li

Research output: Contribution to journalArticleResearchpeer-review

12 Citations (Scopus)


The molecular orientations of conjugated materials on the substrate mainly include edge-on, face-on, and end-on. Edge-on and face-on orientations have been widely observed, while end-on orientation has been rarely reported. Since in organic solar cells (OSCs) charge transport is along the vertical direction, end-on orientation with conjugated backbones perpendicular to the substrate is recognized as the ideal microstructure for OSCs. In this work, we for the first time obtained the preferential end-on orientation in a conjugated molecular dyad that contains a conjugated backbone as donor and perylene bisimide side units as acceptor. This was realized by introducing a fused-ring structure to replace linear terthiophenes with conjugated backbones, yielding F-MDPBI and L-MDPBI respectively. Surprisingly, a shifting trend of the molecular orientation from dominating edge-on in L-MDPBI to preferential end-on in F-MDPBI was observed. As a consequence, vertical charge carrier mobilities in F-MDPBI are one order of magnitude higher than those with preferential edge-on orientation, so single-component OSCs based on this molecular dyad as a single photoactive layer provided a power conversion efficiency of 4.89% compared to 1.70% based on L-MDPBI with preferential edge-on orientation.

Original languageEnglish
Article numbere279
Number of pages9
Issue number2
Publication statusPublished - Apr 2023


  • conjugated molecular dyads
  • crystallinity
  • edge-on
  • end-on
  • single-component organic solar cells

Cite this