title: A small electron donor in cobalt complex electrolyte significantly improves efficiency in dye-sensitized solar cells.
abstract: Photoelectrochemical approach to solar energy conversion demands a kinetic optimization of various light-induced electron transfer processes. Of great importance are the redox mediator systems accomplishing the electron transfer processes at the semiconductor/electrolyte interface, therefore affecting profoundly the performance of various photoelectrochemical cells. Here, we develop a strategy-by addition of a small organic electron donor, tris(4-methoxyphenyl)amine, into state-of-art cobalt tris(bipyridine) redox electrolyte-to significantly improve the efficiency of dye-sensitized solar cells. The developed solar cells exhibit efficiency of 11.7 and 10.5%, at 0.46 and one-sun illumination, respectively, corresponding to a 26% efficiency improvement compared with the standard electrolyte. Preliminary stability tests showed the solar cell retained 90% of its initial efficiency after 250 h continuous one-sun light soaking. Detailed mechanistic studies reveal the crucial role of the electron transfer cascade processes within the new redox system.
authors.affiliation: Department of Chemistry-Ångström, Centre of Molecular Devices, Uppsala University, Box 523, SE-75120 Uppsala, Sweden.
authors.forename: Yan
authors.initials: Y
authors.lastname: Hao
authors.affiliation: Department of Chemistry-Ångström, Centre of Molecular Devices, Uppsala University, Box 523, SE-75120 Uppsala, Sweden.
authors.forename: Wenxing
authors.identifier: 0000-0002-3440-9416
authors.initials: W
authors.lastname: Yang
authors.affiliation: Department of Chemistry-Ångström, Centre of Molecular Devices, Uppsala University, Box 523, SE-75120 Uppsala, Sweden.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Chemistry-Ångström, Centre of Molecular Devices, Uppsala University, Box 523, SE-75120 Uppsala, Sweden.
authors.forename: Roger
authors.initials: R
authors.lastname: Jiang
authors.affiliation: Department of Chemistry-Ångström, Centre of Molecular Devices, Uppsala University, Box 523, SE-75120 Uppsala, Sweden.
authors.forename: Edgar
authors.initials: E
authors.lastname: Mijangos
authors.affiliation: Laboratory of Photomolecular Science, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, EPFL SB ISIC LSPM, Chemin des Alambics, Station 6, CH-1015 Lausanne, Switzerland.
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Saygili
authors.affiliation: Department of Chemistry-Ångström, Centre of Molecular Devices, Uppsala University, Box 523, SE-75120 Uppsala, Sweden.
authors.forename: Leif
authors.initials: L
authors.lastname: Hammarström
authors.affiliation: Department of Chemistry-Ångström, Centre of Molecular Devices, Uppsala University, Box 523, SE-75120 Uppsala, Sweden.|Laboratory of Photomolecular Science, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, EPFL SB ISIC LSPM, Chemin des Alambics, Station 6, CH-1015 Lausanne, Switzerland.
authors.forename: Anders
authors.initials: A
authors.lastname: Hagfeldt
authors.affiliation: Department of Chemistry-Ångström, Centre of Molecular Devices, Uppsala University, Box 523, SE-75120 Uppsala, Sweden.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Boschloo