Exciton and Charge Carrier Dynamics in Highly Crystalline PTQ10:IDIC Organic Solar Cells

Hyojung Cha, Yizhen Zheng, Yifan Dong, Hyun Hwi Lee, Jiaying Wu, Helen Bristow, Jiangbin Zhang, Harrison Ka Hin Lee, Wing C. Tsoi, Artem A. Bakulin, Iain McCulloch, James R. Durrant

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Herein the morphology and exciton/charge carrier dynamics in bulk heterojunctions (BHJs) of the donor polymer PTQ10 and molecular acceptor IDIC are investigated. PTQ10:IDIC BHJs are shown to be particularly promising for low cost organic solar cells (OSCs). It is found that both PTQ10 and IDIC show remarkably high crystallinity in optimized BHJs, with GIWAXS data indicating pi-pi stacking coherence lengths of up to 8 nm. Exciton-exciton annihilation studies indicate long exciton diffusion lengths for both neat materials (19 nm for PTQ10 and 9.5 nm for IDIC), enabling efficient exciton separation with half lives of 1 and 3 ps, despite the high degree of phase segregation in this blend. Transient absorption data indicate exciton separation leads to the formation of two spectrally distinct species, assigned to interfacial charge transfer (CT) states and separated charges. CT state decay is correlated with the appearance of additional separate charges, indicating relatively efficient CT state dissociation, attributed to the high crystallinity of this blend. The results emphasize the potential for high material crystallinity to enhance charge separation and collection in OSCs, but also that long exciton diffusion lengths are likely to be essential for efficient exciton separation in such high crystallinity devices.

Original languageEnglish (US)
Article number2001149
JournalAdvanced Energy Materials
Issue number38
StatePublished - Oct 1 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • General Materials Science


  • charge separation
  • nonfullerene acceptors
  • organic solar cells
  • phase separation
  • recombination


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