Optimized Fibril Network Morphology by Precise Side‐Chain Engineering to Achieve High‐Performance Bulk‐Heterojunction Organic Solar Cells

Journal Article · Fri May 18 00:00:00 EDT 2018 · Advanced Materials

DOI:https://doi.org/10.1002/adma.201707353· OSTI ID:1437881

Liu, Tao ^[1]; Huo, Lijun ^[1]; Chandrabose, Sreelakshmi ^[2]; Chen, Kai ^[2]; Han, Guangchao ^[3]; Qi, Feng ^[1]; Meng, Xiangyi ^[4]; Xie, Dongjun ^[5]; Ma, Wei ^[4]; Yi, Yuanping ^[3]; Hodgkiss, Justin M. ^[2]; Liu, Feng ^[6]; Wang, Jing ^[6]; Yang, Chuluo ^[5]; Sun, Yanming  ^[1]

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1. Heeger Beijing Research and Development Center School of Chemistry Beihang University Beijing 100191 China
2. MacDiarmid Institute for Advanced Materials and Nanotechnology and School of Chemical and Physical Sciences Victoria University of Wellington Wellington 6010 New Zealand
3. Beijing National Laboratory for Molecular Science Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 P. R. China
4. State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an 710049 China
5. Hubei Key Lab on Organic and Polymeric Optoelectronic Materials Department of Chemistry Wuhan University Wuhan 430072 P. R. China
6. School of Physics and Astronomy and Collaborative Innovation Center of IFSA (CICIFSA) Shanghai Jiao Tong University Shanghai 200240 P. R. China

Abstract A polymer fibril assembly can dictate the morphology framework, in forming a network structure, which is highly advantageous in bulk heterojunction (BHJ) organic solar cells (OSCs). A fundamental understanding of how to manipulate such a fibril assembly and its influence on the BHJ morphology and device performance is crucially important. Here, a series of donor–acceptor polymers, PBT1‐O, PBT1‐S, and PBT1‐C, is used to systematically investigate the relationship between molecular structure, morphology, and photovoltaic performance. The subtle atom change in side chains is found to have profound effect on regulating electronic structure and self‐assembly of conjugated polymers. Compared with PBT1‐O and PBT1‐S, PBT1‐C‐based OSCs show much higher photovoltaic performance with a record fill factor (FF) of 80.5%, due to the formation of optimal interpenetrating network morphology. Such a fibril network strategy is further extended to nonfullerene OSCs using a small‐molecular acceptor, which shows a high efficiency of 12.7% and an FF of 78.5%. The results indicate the formation of well‐defined fibrillar structure is a promising approach to achieving a favorable morphology in BHJ OSCs.

• Sponsoring Organization: USDOE
• Grant/Contract Number: DE‐AC02‐05CH11231
• OSTI ID: 1437881
• Journal Information: Advanced Materials, Journal Name: Advanced Materials Vol. 30 Journal Issue: 26; ISSN 0935-9648
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: Germany
• Language: English