title: Easy Access to NO2 -Containing Donor-Acceptor-Acceptor Electron Donors for High Efficiency Small-Molecule Organic Solar Cells.
abstract: Two donor-acceptor-acceptor (D-A-A)-type molecules incorporating nitrobenzoxadiazole (NBO) as the A-A block and ditolylamine as the D block bridged through a phenylene (PNBO) and a thiophene (TNBO) spacer were synthesized in a one-step coupling reaction. Their electronic, photophysical, and thermal properties; crystallographic analysis; and theoretical calculations were studied to establish a clear structure-property relationship. The results indicate that the quinoidal character of the thiophene bridge strongly governs the structural features and crystal packings (herringbone vs. brickwork) and thus the physical properties of the compounds. PNBO and TNBO were utilized as electron donors combined with C70 as the electron acceptor in the active layer of vacuum-processed bulk heterojunction small-molecule organic solar cells (SMOSCs). The power conversion efficiency of both PNBO- and TNBO-based OSCs exceeded 5 %. The ease of accessibility of PNBO and TNBO demonstrates the potential for simple and economical synthesis of electron donors in vacuum-processed SMOSCs.
authors.affiliation: Department of Chemistry, National Taiwan University, Taiwan.
authors.forename: Hao-Chun
authors.initials: HC
authors.lastname: Ting
authors.affiliation: Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taiwan.
authors.forename: Ya-Ting
authors.initials: YT
authors.lastname: Yang
authors.affiliation: Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taiwan.
authors.forename: Chia-Hsun
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taiwan. jiunhawlee@ntu.edu.tw.
authors.forename: Jiun-Haw
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taiwan.
authors.forename: Jung-Hung
authors.initials: JH
authors.lastname: Chang
authors.affiliation: Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taiwan.
authors.forename: Chih-I
authors.initials: CI
authors.lastname: Wu
authors.affiliation: Department of Photonics Engineering, Yuan Ze University, Taiwan.
authors.forename: Tien-Lung
authors.initials: TL
authors.lastname: Chiu
authors.affiliation: Department of Electro-Optical Engineering, National United University, Taiwan.
authors.forename: Chi-Feng
authors.initials: CF
authors.lastname: Lin
authors.affiliation: Department of Chemistry, National Taiwan University, Taiwan.
authors.forename: Chin-Lung
authors.initials: CL
authors.lastname: Chung
authors.affiliation: Department of Chemistry, National Taiwan University, Taiwan. kenwong@ntu.edu.tw.|Institute of Atomic and Molecular Science, Academia Sinica, Taiwan. kenwong@ntu.edu.tw.
authors.forename: Ken-Tsung
authors.initials: KT
authors.lastname: Wong
mesh_terms: D001554:Benzene / Q000737:chemistry*; D011211:Electric Power Supplies; D004563:Electrochemistry; D004579:Electron Transport; D008958:Models, Molecular; D008968:Molecular Conformation; D009585:Nitrogen Dioxide / Q000737:chemistry*; D011789:Quantum Theory; D012993:Solar Energy; D013696:Temperature; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D013876:Thiophenes; D001554:Benzene; D009585:Nitrogen Dioxide
keywords: electrochemistry; electron transfer; organic photovoltaics; photochemistry; structure-property relationships