Imide-functionalized acceptor-acceptor copolymers as efficient electron transport layers for high-performance perovskite solar cells

Yongqiang Shi, Wei Chen, Ziang Wu, Yang Wang, Weipeng Sun, Kun Yang, Yumin Tang, Han Young Woo, Ming Zhou, Aleksandra B. Djurišić, Zhubing He, Xugang Guo

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


Electron transport layers (ETLs) are critical for improving device performance and stability of perovskite solar cells (PVSCs). Herein, a distannylated electron-deficient bithiophene imide (BTI-Tin) is synthesized, which enables us to access structurally novel acceptor-acceptor (A-A) type polymers. Polymerizing BTI-Tin with dibrominated naphthalene diimide (NDI-Br) and perylene diimide (PDI-Br) affords two A-A copolymers P(BTI-NDI) and P(BTI-PDI). The all-acceptor backbone yields both low-lying highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels for the polymers, which combined with their high electron mobility render P(BTI-NDI) and P(BTI-PDI) as promising ETLs for perovskite solar cells (PVSCs). When applied as ETLs to replace the conventional [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) in planar p-i-n PVSCs, the PC61BM-free devices based on P(BTI-NDI) and P(BTI-PDI) achieve remarkable power conversion efficiencies (PCEs) of 19.5% and 20.8%, respectively, with negligible hysteresis. Such performance is attributed to efficient electron extraction and reduced charge recombination. Moreover, the devices based on P(BTI-NDI) and P(BTI-PDI) ETLs show improved stability compared to the PC61BM based ones due to the higher hydrophobicity of the new ETLs. This work provides important guidelines for designing n-type polymers to replace PC61BM as efficient ETLs for high-performance PVSCs with improved stability.

Original languageEnglish
Pages (from-to)13754-13762
Number of pages9
JournalJournal of Materials Chemistry A
Issue number27
Publication statusPublished - 2020 Jul 21

Bibliographical note

Funding Information:
Science and Technology Innovation JCYJ20170817105905899 and JCYJ20180504165709042). Z. H. is grateful to the National Natural Science Foundation of China (NSFC, No. 61775091), National Key Research Project MOST (No. 2016YFA0202400), and the Shenzhen Science and Technology Innovation Commission (No. ZDSYS201602261933302 and CYJ20180504165851864). Y. S. thanks the Innovative Research Foundation of Southwest Petroleum University (2019cxyb011). H. Y. W. is grateful for the nancial support from the National Research Foundation (NRF) of Korea (NRF-2016M1A2A2940911 and 2019R1A6A1A11044070). The authors thank the Materials Characterization and Preparation Center (MCPC) and the Pico Center of SUSTech for some characterizations in this work.

Publisher Copyright:
© 2020 The Royal Society of Chemistry.

ASJC Scopus subject areas

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


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