title: Small molecules based on benzo[1,2-b:4,5-b']dithiophene unit for high-performance solution-processed organic solar cells.
abstract: Small molecules, namely, DCAO(3)TBDT and DR(3)TBDT, with 2-ethylhexoxy substituted BDT as the central building block and octyl cyanoacetate and 3-ethylrhodanine as different terminal units with the same linkage of dioctyltertthiophene, have been designed and synthesized. The photovoltaic properties of these two molecules as donors and fullerene derivatives as the acceptors in bulk heterojunction solar cells are studied. Among them, DR(3)TBDT shows excellent photovoltaic performance, and power conversion efficiency as high as 7.38% (certified 7.10%) under AM 1.5G irradiation (100 mW cm(-2)) has been achieved using the simple solution spin-coating fabrication process, which is the highest efficiency reported to date for any small-molecule-based solar cells. The results demonstrate that structure fine turning could cause significant performance difference and with that the performance of solution-processed small-molecule solar cells can indeed be comparable with or even surpass their polymer counterparts.
authors.affiliation: Key Laboratory for Functional Polymer Materials and Centre for Nanoscale Science and Technology, Institute of Polymer Chemistry, Nankai University, Tianjin 300071, China.
authors.forename: Jiaoyan
authors.initials: J
authors.lastname: Zhou
authors.forename: Xiangjian
authors.initials: X
authors.lastname: Wan
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Liu
authors.forename: Yi
authors.initials: Y
authors.lastname: Zuo
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.forename: Guangrui
authors.initials: G
authors.lastname: He
authors.forename: Guankui
authors.initials: G
authors.lastname: Long
authors.forename: Wang
authors.initials: W
authors.lastname: Ni
authors.forename: Chenxi
authors.initials: C
authors.lastname: Li
authors.forename: Xuncheng
authors.initials: X
authors.lastname: Su
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Chen