Graded bulk-heterojunction enables 17% binary organic solar cells via nonhalogenated open air coating

Ying Zhang, Kuan Liu, Jiaming Huang, Xinxin Xia, Jiupeng Cao, Guangming Zhao, Patrick W.K. Fong, Ye Zhu, Feng Yan, Yang Yang, Xinhui Lu, Gang Li

Research output: Journal article publicationJournal articleAcademic researchpeer-review

82 Citations (Scopus)


Graded bulk-heterojunction (G-BHJ) with well-defined vertical phase separation has potential to surpass classical BHJ in organic solar cells (OSCs). In this work, an effective G-BHJ strategy via nonhalogenated solvent sequential deposition is demonstrated using nonfullerene acceptor (NFA) OSCs. Spin-coated G-BHJ OSCs deliver an outstanding 17.48% power conversion efficiency (PCE). Depth-profiling X-ray photoelectron spectroscopy (DP-XPS) and angle-dependent grazing incidence X-ray diffraction (GI-XRD) techniques enable the visualization of polymer/NFA composition and crystallinity gradient distributions, which benefit charge transport, and enable outstanding thick OSC PCEs (16.25% for 300 nm, 14.37% for 500 nm), which are among the highest reported. Moreover, the nonhalogenated solvent enabled G-BHJ OSC via open-air blade coating and achieved a record 16.77% PCE. The blade-coated G-BHJ has drastically different D-A crystallization kinetics, which suppresses the excessive aggregation induced unfavorable phase separation in BHJ. All these make G-BHJ a feasible and promising strategy towards highly efficient, eco- and manufacture friendly OSCs.

Original languageEnglish
Article number4815
Pages (from-to)1-13
Number of pages13
JournalNature Communications
Issue number1
Publication statusPublished - Dec 2021

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)


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