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Effects of Bithiophene Imide Fusion on the Device Performance of Organic Thin‐Film Transistors and All‐Polymer Solar Cells
Author(s) -
Wang Yingfeng,
Yan Zhenglong,
Guo Han,
Uddin Mohammad Afsar,
Ling Shaohua,
Zhou Xin,
Su Huimin,
Dai Junfeng,
Woo Han Young,
Guo Xugang
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201708421
Subject(s) - materials science , diimide , imide , polymer , perylene , crystallinity , electron mobility , homo/lumo , polymer solar cell , band gap , polymer chemistry , photochemistry , optoelectronics , chemistry , organic chemistry , molecule , composite material
Two new bithiophene imide (BTI)‐based n‐type polymers were synthesized. f‐BTI2‐FT based on a fused BTI dimer showed a smaller band gap, a lower LUMO, and higher crystallinity than s‐BTI2‐FT containing a BTI dimer connected through a single bond. s‐BTI2‐FT exhibited a remarkable electron mobility of 0.82 cm 2 V −1 s −1 , and f‐BTI2‐FT showed a further improved mobility of 1.13 cm 2 V −1 s −1 in transistors. When blended with the polymer donor PTB7‐Th, f‐BTI2‐FT‐based all‐polymer solar cells (all‐PSCs) attained a PCE of 6.85 %, the highest value for an all‐PSC not based on naphthalene (or perylene) diimide polymer acceptors. However, s‐BTI2‐FT all‐PSCs showed nearly no photovoltaic effect. The results demonstrate that f‐BTI2‐FT is one of most promising n‐type polymers and that ring fusion offers an effective approach for designing polymers with improved electrical properties.