C70-based aqueous-soluble fullerene for the water composition-tolerant performance of eco-friendly polymer solar cells

Changkyun Kim, Hyunbum Kang, Nayoun Choi, Seungjin Lee, Youngkwon Kim, Jinwoo Kim, Ziang Wu, Han Young Woo, Bumjoon J. Kim

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Eco-friendly polymer solar cells (eco-PSCs) based on aqueous-soluble conjugated materials have recently received great research attention. In this work, we report the development of an aqueous-processable C70-based fullerene derivative (PC71BO15) for eco-PSCs processed by water/ethanol co-solvents. The desirable aggregation behavior and enhanced light absorption ability of PC71BO15 have enabled the fabrication of PPDT2FBT-A:PC71BO15-based eco-PSCs with power conversion efficiencies (PCEs) of up to 2.51%, which is the highest value reported to date for aqueous-processed PSCs. These PPDT2FBT-A:PC71BO15 eco-PSCs exhibit significantly higher PCEs than those of the reference PPDT2FBT-A:PC61BO15 devices over all device-processable water/ethanol compositions. At the optimal water/ethanol composition (v/v = 15 : 85), the PCE of the PPDT2FBT-A:PC71BO15 eco-PSCs is 73% higher than that of the PC61BO15-based counterparts, as a result of enhanced light absorption. Importantly, the PC71BO15-based eco-PSCs show much higher tolerance in their PCEs to the water/ethanol composition. For example, the PCEs of the PPDT2FBT-A : PC71BO15 eco-PSCs at a 30 : 70 water/ethanol ratio maintain 89% of the optimal performance at a 15 : 85 ratio, whereas the PC61BO15-based devices only maintain 45%. This large difference in terms of water-tolerant behavior is mainly related to the different aggregation behaviors between PC71BO15 and PC61BO15 in blend films, which are carefully investigated using electrical, optical and morphological characterizations. This high water composition-tolerance affords an excellent reproducibility of the PC71BO15-based eco-PSCs with eco/human-friendly aqueous processing under ambient conditions.

Original languageEnglish
Pages (from-to)15224-15233
Number of pages10
JournalJournal of Materials Chemistry C
Issue number43
Publication statusPublished - 2020 Nov 21

Bibliographical note

Funding Information:
This research was supported by a National Research Foundation (NRF) Grant (2017M3A7B8065584, 2020M3D1A1069831, and 2020M3D1A2102869). We thank Prof. Biwu Ma and Dr. Graham Collier for the helpful discussions.

Publisher Copyright:
© The Royal Society of Chemistry.

ASJC Scopus subject areas

  • General Chemistry
  • Materials Chemistry


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