Phthalimide-Based High Mobility Polymer Semiconductors for Efficient Nonfullerene Solar Cells with Power Conversion Efficiencies over 13%

Jianwei Yu, Peng Chen, Chang Woo Koh, Hang Wang, Kun Yang, Xin Zhou, Bin Liu, Qiaogan Liao, Jianhua Chen, Huiliang Sun, Han Young Woo, Shiming Zhang, Xugang Guo

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)


Highly efficient nonfullerene polymer solar cells (PSCs) are developed based on two new phthalimide-based polymers phthalimide-difluorobenzothiadiazole (PhI-ffBT) and fluorinated phthalimide-ffBT (ffPhI-ffBT). Compared to all high-performance polymers reported, which are exclusively based on benzo[1,2-b:4,5-b′]dithiophene (BDT), both PhI-ffBT and ffPhI-ffBT are BDT-free and feature a D-A1-D-A2 type backbone. Incorporating a second acceptor unit difluorobenzothiadiazole leads to polymers with low-lying highest occupied molecular orbital levels (≈−5.6 eV) and a complementary absorption with the narrow bandgap nonfullerene acceptor IT-4F. Moreover, these BDT-free polymers show substantially higher hole mobilities than BDT-based polymers, which are beneficial to charge transport and extraction in solar cells. The PSCs containing difluorinated phthalimide-based polymer ffPhI-ffBT achieve a substantial PCE of 12.74% and a large Voc of 0.94 V, and the PSCs containing phthalimide-based polymer PhI-ffBT show a further increased PCE of 13.31% with a higher Jsc of 19.41 mA cm−2 and a larger fill factor of 0.76. The 13.31% PCE is the highest value except the widely studied BDT-based polymers and is also the highest among all benzothiadiazole-based polymers. The results demonstrate that phthalimides are excellent building blocks for enabling donor polymers with the state-of-the-art performance in nonfullerene PSCs and the BDT is not necessary for constructing such donor polymers.

Original languageEnglish
Article number1801743
JournalAdvanced Science
Issue number2
Publication statusPublished - 2019 Jan 23


  • difluorobenzothiadiazole
  • high mobility polymers
  • high power conversion efficiencies
  • nonfullerene polymer solar cells
  • phthalimide

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Biochemistry, Genetics and Molecular Biology (miscellaneous)
  • Engineering(all)
  • Physics and Astronomy(all)


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