title: β-Functionalized Push-Pull Porphyrin Sensitizers in Dye-Sensitized Solar Cells: Effect of π-Conjugated Spacers.
abstract: A series of new β-functionalized push-pull-structured porphyrin dyes were synthesized so as to investigate the effect of the π-conjugated spacer on the performance of dye-sensitized solar cells (DSSCs). Suzuki- and Heck-type palladium-catalyzed coupling methodologies were used to obtain various β-functionalized porphyrins and β-benzoic acid (ZnPHn) and β-vinylbenzoic acid (ZnPVn) derivatives from β-borylated porphyrin precursors. Photophysical studies of the resulting porphyrins revealed a clear dependence on the nature of the β linker. In particular, it was found that a β-vinylene linkage perturbs the electronic structure of the porphyrin core; this is less true for a β-phenyl linkage. Theoretical analyses provided support for the intrinsic intramolecular charge-transfer character of the β-functionalized, push-pull porphyrins of this study. The extent of charge transfer depends on the nature of the β-conjugated linkage. The photovoltaic performances of the cells sensitized with β-phenylenevinylene ZnPVn exhibited higher power conversion efficiency values than those bearing β-phenyl linkages (ZnPHn). This was ascribed to differences in light-harvesting efficiency. Furthermore, compared to the use of a standard iodine-based electrolyte, the DSSC performance of cells made from the present porphyrins was improved by more than 1 % upon using a cobalt(II/III)-based electrolyte. Under standard AM 1.5 illumination, the highest efficiency, 8.2 %, was obtained by using cells made from the doubly β-butadiene-linked porphyrin.
authors.affiliation: Department of Chemistry, Yonsei University, Seoul, 120-749 (Korea).|Education Center for Global Leaders in Molecular Systems for Devices, Kyushu University, Fukuoka 819-0395 (Japan).
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Ishida
authors.affiliation: Department of Chemistry, Yonsei University, Seoul, 120-749 (Korea).|Optoelectronic Materials Lab, Korea Institute of Science and Technology, Seoul 130-650 (Korea).
authors.forename: Daesub
authors.initials: D
authors.lastname: Hwang
authors.affiliation: Department of Chemistry & Biochemistry, University of Texas at Austin, Texas 78712-1224 (USA).
authors.forename: Zhan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Yonsei University, Seoul, 120-749 (Korea).
authors.forename: Yung Ji
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Department of Chemistry, Yonsei University, Seoul, 120-749 (Korea).
authors.forename: Juwon
authors.initials: J
authors.lastname: Oh
authors.affiliation: Department of Chemistry & Biochemistry, University of Texas at Austin, Texas 78712-1224 (USA).
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Lynch
authors.affiliation: Optoelectronic Materials Lab, Korea Institute of Science and Technology, Seoul 130-650 (Korea).
authors.forename: Dong Young
authors.initials: DY
authors.lastname: Kim
authors.affiliation: Department of Chemistry, Yonsei University, Seoul, 120-749 (Korea). sessler@cm.utexas.edu.|Department of Chemistry & Biochemistry, University of Texas at Austin, Texas 78712-1224 (USA). sessler@cm.utexas.edu.
authors.forename: Jonanthan L
authors.initials: JL
authors.lastname: Sessler
authors.affiliation: Department of Chemistry, Yonsei University, Seoul, 120-749 (Korea). dongho@yonsei.ac.kr.
authors.forename: Dongho
authors.initials: D
authors.lastname: Kim
mesh_terms: D000327:Adsorption; D004396:Coloring Agents / Q000737:chemistry*; D017319:Photosensitizing Agents / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D012993:Solar Energy
chemical_list: D004396:Coloring Agents; D017319:Photosensitizing Agents; D011166:Porphyrins
keywords: cross-coupling; density functional calculations; donor-acceptor systems; porphyrins; solar cells