Improving Photovoltaic Performance of a Fused‐Ring Azepinedione Copolymer via a D–A–A Design. Issue 8 (13th February 2018)

• Record Type: Journal Article
• Authors: Zhang, Honghong; Li, Ting; Xiao, Zuo; Lei, Zhongli; Ding, Liming
• Is Part Of: Macromolecular rapid communications. Volume 39:Issue 8(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-02-13
• Subjects: D–A–A copolymer -- mobility -- polymer solar cells; Macromolecules -- Periodicals; Polymers -- Periodicals; Chemistry -- Periodicals; 547.705
• DOI: 10.1002/marc.201700882
• Languages: English
• ISSNs: 1022-1336

Abstract

Abstract: Two conjugated copolymer donors, PTTABDT and PBTTABDT, based on a fused‐ring azepinedione acceptor unit, 5‐(2‐octyldodecyl)‐4H‐thieno[2′, 3′:4, 5]thieno[3, 2‐c]thieno[2′, 3′:4, 5]thieno[2, 3‐e]azepine‐4, 6(5H)‐dione (TTA), are prepared. PTTABDT possesses a conventional donor–acceptor (D–A) structure with one TTA in the repeat unit, while PBTTABDT has a D–A–A structure with two TTAs in the repeat unit. Compared with PTTABDT, PBTTABDT shows a deeper highest occupied molecular orbital (HOMO) level, a narrower bandgap, and a higher hole mobility, and exhibits better performance in bulk heterojunction solar cells. Power conversion efficiencies of 6.18% and 7.81% are achieved from PTTABDT:PC71 BM and PBTTABDT:PC71 BM solar cells, respectively. The higher performance of PBTTABDT:PC71 BM solar cells results from the enhanced open‐circuit voltage ( V oc ) and short‐circuit current density ( J sc ). Abstract : A D–A–A copolymer donor (PBTTABDT) based on a fused‐ring azepinedione acceptor unit is developed. Compared with D–A counterpart PTTABDT, PBTTABDT possesses a deeper highest occupied molecular orbital (HOMO) level, a narrower bandgap, and a higher hole mobility. PBTTABDT:PC71 BM solar cells give a power conversion efficiency of 7.81%.