Tetracoordinated Bis-phenanthroline Copper-Complex Couple as Efficient Redox Mediators for Dye Solar Cells

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• 作者：Mirko Magni ; Roberto Giannuzzi ; Alessia Colombo ; Maria Pia Cipolla ; Claudia Dragonetti ; Stefano Caramori ; Stefano Carli ; Roberto Grisorio ; Gian Paolo Suranna ; Carlo Alberto Bignozzi ; Dominique Roberto ; Michele Manca
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：June 6, 2016
• 年：2016
• 卷：55
• 期：11
• 页码：5245-5253
• 全文大小：520K
• 年卷期：0
• ISSN：1520-510X

文摘

A tetracoordinated redox couple, made by [Cu(2-mesityl-4,7-dimethyl-1,10-phenanthroline)₂][PF₆], 1, and its Cu(II) form [Cu(2-mesityl-4,7-dimethyl-1,10-phenanthroline)₂][PF₆]₂, 2, has been synthesized, and its electrochemical and photochemical features have been investigated and compared with those of a previously published Cu²⁺/Cu⁺ redox shuttle, namely, [Cu(2,9-dimethyl-1,10-phenanthroline)₂][PF₆], 3, and its pentacoordinated oxidized form [Cu(2,9-dimethyl-1,10-phenanthroline)₂Cl][PF₆], 4. The detrimental effect of the fifth Cl^– ancillary ligand on the charge transfer kinetics of the redox shuttles has been exhaustively demonstrated. Appropriately balanced Cu-based electrolytes have been then formulated and tested in dye solar cells in combination with a π-extended benzothiadiazole dye. The bis-phenanthroline Cu-complexes, 1 and 2, have been found to provide an overall 4.4% solar energy conversion efficiency, which is more than twice that of the literature benchmark couple, 3 and 4, employing a Cl-coordinated oxidized species and even comparable with the performances of a I^–/I₃^– electrolyte of analogous concentration. A fast counter-electrode reaction, due to the excellent electrochemical reversibility of 2, and a high electron collection efficiency, allowed through the efficient dye regeneration kinetics exerted by 1, represents two major characteristics of these copper-based electron mediators and may constitute a pivotal step toward the development of a next generation of copper-based efficient iodine-free redox shuttles.