title: Alcohol-soluble Star-shaped Oligofluorenes as Interlayer for High Performance Polymer Solar Cells.
abstract: Two star-shaped oligofluorenes with hexakis(fluoren-2-yl)benzene as core are designed and sythesized for interfacial materials in polymer solar cell. Diethanolamino groups are attached to the side chain of fluorene units for T0-OH and T1-OH to enable the alcohol solubility, and additional hydrophobic n-hexyl chains are also grafted on the increased fluorene arms for T1-OH. In conventional device with PCDTBT/PC71BM as active layer, a 50% enhanced PCE is obtained by incorporating T0-OH and T1-OH as the interlayer compared with device without interlayer. By optimizing the active material with PTB7 and with the inverted device structure, a maximum PCE of 9.30% is achieved, which is among the highest efficiencies for PTB7 based polymer solar cells. The work function of modified electrode, the surface morphology and the suraface properties are systematically studied. By modifying the structures of the star-shaped molecules, a balance between the hydrophobic and hydrophilic property is finely tuned, and thus facilitate the interlayer for high performance of PSCs.
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zou
authors.affiliation: Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Device, South China University of Technology, Guangzhou 510640, China.
authors.forename: Zhicai
authors.initials: Z
authors.lastname: He
authors.affiliation: Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Device, South China University of Technology, Guangzhou 510640, China.
authors.forename: Baofeng
authors.initials: B
authors.lastname: Zhao
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Chuluo
authors.initials: C
authors.lastname: Yang
authors.affiliation: Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Device, South China University of Technology, Guangzhou 510640, China.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Wu
authors.affiliation: Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Device, South China University of Technology, Guangzhou 510640, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao