title: New benzo[1,2-b:4,5-b']dithiophene-based small molecules containing alkoxyphenyl side chains for high efficiency solution-processed organic solar cells.
abstract: A new acceptor-donor-acceptor (A-D-A) small molecule, namely, BDT-PO-DPP, based on the alkoxyphenyl (PO)-substituted benzo[1,2-b:4,5-b']dithiophene (BDT) derivative and the diketopyrrolopyrrole (DPP) unit was synthesized as an electron donor for solution-processed small-molecule organic solar cells (SMOSCs). BDT-PO-DPP exhibited good thermal stability, with a 5 % weight-lost temperature at 401 °C under a nitrogen atmosphere. BDT-PO-DPP exhibited a lower HOMO energy level of -5.25 eV and a weaker aggregation ability than alkoxy-substituted BDT-O-DPP. A bulk heterojunction SMOSC device based on BDT-PO-DPP and [6,6]-phenyl-C61 -butyric acid methyl ester was prepared, and it showed a power conversion efficiency up to 5.63% with a high open-circuit voltage of 0.83 V, a short circuit current density of 11.23 mA cm(-2) , and a fill factor of 60.37% by using 1,2-dichlorobenzene as the co-solvent after thermal annealing at 110 °C. The results indicate that the alkoxyphenyl-substituted BDT derivative is a promising electron-donor building block for constructing highly efficient solution-processed SMOSCs.
authors.affiliation: CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (PR China), Fax: (+86) 532-80662778; University of Chinese Academy of Sciences, Beijing 100049 (PR China).
authors.forename: Zhengkun
authors.initials: Z
authors.lastname: Du
authors.forename: Weichao
authors.initials: W
authors.lastname: Chen
authors.forename: Shuguang
authors.initials: S
authors.lastname: Wen
authors.forename: Shanlin
authors.initials: S
authors.lastname: Qiao
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.forename: Dan
authors.initials: D
authors.lastname: Ouyang
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.forename: Xichang
authors.initials: X
authors.lastname: Bao
authors.forename: Renqiang
authors.initials: R
authors.lastname: Yang
mesh_terms: D011211:Electric Power Supplies; D006358:Hot Temperature; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D018625:Microscopy, Atomic Force; D013472:Sunlight; D013818:Thermogravimetry; D013876:Thiophenes / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D013876:Thiophenes
keywords: donor-acceptor systems; energy conversion; organic solar cells; small molecules; thin films