title: Conjugated Oligothiophene Derivatives Based on Bithiophene with Unsaturated Bonds as Building Blocks for Solution-Processed Bulk Heterojunction Organic Solar Cells.
abstract: A new building block ATVTA that uses stiff carbon-carbon triple bonds (A) on 1,2-di(2-thienyl)-ethene (TVT) has been developed. Oligothiophene derivatives S-01 with a TVT unit, S-02 with a 5,5'-diethynyl-2,2'-dithienyl (AT2) unit and S-03 with ATVTA were synthesized to compare their effects in a systematic study. Due to the better π-conjugation extension of the TVT unit, S-01 exhibits the most red-shifted absorption profile among them, whereas S-02 possesses the deepest HOMO level. While the HOMO level of S-03 is down-shifted by 0.02 eV relative to that of S-01, the alkyne linkages can effectively down-shift the HOMO level. By replacing the terminal units of S-03 with stronger electron acceptors, S-04 and S-05 exhibited broader absorption profiles and lower HOMO levels than those of S-03. Organic solar cells based on these molecules were fabricated and an S-03:PC60BM (1:1, w/w) based device afforded the highest Vocvalue of 0.96 V and a power conversion efficiency (PCE) of 2.19 %.
authors.affiliation: Institute of Molecular Functional Materials, Department of Chemistry and Institute of Advanced Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P.R. China.|Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China.
authors.forename: Chaohua
authors.initials: C
authors.lastname: Cui
authors.affiliation: Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, P.R. China.
authors.forename: Man-Sing
authors.initials: MS
authors.lastname: Cheung
authors.affiliation: Institute of Molecular Functional Materials, Department of Chemistry and Institute of Advanced Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P.R. China.
authors.forename: Cheuk-Lam
authors.initials: CL
authors.lastname: Ho
authors.affiliation: MOE Key Laboratory for Interface Science and Engineering in Advanced Materials, Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, 79 Yingze West Street, Taiyuan, 030024, P.R. China.
authors.forename: Qingchen
authors.initials: Q
authors.lastname: Dong
authors.affiliation: Department of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, P.R. China.
authors.forename: Zhenyang
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P.R. China.
authors.forename: Yongfang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Molecular Functional Materials, Department of Chemistry and Institute of Advanced Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P.R. China.|Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, P.R. China.
authors.forename: Wai-Yeung
authors.initials: WY
authors.lastname: Wong
keywords: alkynes; conjugation; oligothiophenes; organic solar cells; synthesis