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A Nonconjugated Zwitterionic Polymer: Cathode Interfacial Layer Comparable with PFN for Narrow‐Bandgap Polymer Solar Cells
Author(s) -
Li Zhendong,
Chen Qiaoyun,
Liu Yanfeng,
Ding Lan,
Zhang Kaicheng,
Zhu Kai,
Yuan Ligang,
Dong Bin,
Zhou Yi,
Song Bo
Publication year - 2018
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201700828
Subject(s) - polymer , materials science , methacrylate , cathode , solvent , chemical engineering , band gap , polymer solar cell , solubility , polymer chemistry , optoelectronics , organic chemistry , copolymer , composite material , chemistry , engineering
A nonconjugated, alcohol‐soluble zwitterionic polymer, poly(sulfobetaine methacrylate) (denoted by PSBMA), is employed as cathode interfacial layer (CIL) in polymer solar cells (PSCs) based on PTB7‐Th:PC 71 BM. Compared with the control device without CIL, PSCs with PSBMA CILs show significant enhancement on the resulting performance, and the highest power conversion efficiency (PCE) of 8.27% is achieved. Under parallel conditions, PSCs with PSBMA as CIL show comparable performance than those with widely used poly[(9,9‐bis(30‐( N , N ‐dimethylamino)propyl)‐2,7‐fluorene)‐ alt ‐2,7‐(9,9‐ioctylfluorene)] as CIL. The polar groups of PSBMA not only provide a solvent orthogonal solubility in the process of preparation of the devices but also lead to interfacial dipole to the electrode, which promises a better energy level alignment. In addition, PSBMA‐based devices show better abilities of hole blocking. These results indicate that the zwitterionic polymer PSBMA should be a promising CIL in PSC‐based narrow‐bandgap polymers.