Supramolecular Hemicage Cobalt Mediators for Dye‐Sensitized Solar Cells |
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| Authors: | Dr Marina Freitag Wenxing Yang Dr Lisa A Fredin Luca D'Amario Dr K Martin Karlsson Prof Anders Hagfeldt Prof Gerrit Boschloo |
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| Institution: | 1. Ecole Polytechnique Fédérale de Lausanne, Laboratory for Photomolecular Science, Institute of Chemical Sciences and Engineering, Station 6, Lausanne, Switzerland;2. Uppsala University, Physical Chemistry, ?ngstr?m Laboratory, Uppsala, Sweden;3. Chemical Informatics Research Group, Chemical Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, USA;4. Dyenamo AB, Stockholm, Sweden |
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| Abstract: | A new class of dye‐sensitized solar cells (DSSCs) using the hemicage cobalt‐based mediator Co(ttb)]2+/3+ with the highly preorganized hexadentate ligand 5,5′′,5′′′′‐((2,4,6‐triethyl benzene‐1,3,5‐triyl)tris(ethane‐2,1‐diyl))tri‐2,2′‐bipyridine (ttb) has been fully investigated. The performances of DSSCs sensitized with organic D –π–A dyes utilizing either Co(ttb)]2+/3+ or the conventional Co(bpy)3]2+/3+ (bpy=2,2′‐bipyridine) redox mediator are comparable under 1000 W m?2 AM 1.5 G illumination. However, the hemicage complexes exhibit exceptional stability under thermal and light stress. In particular, a 120‐hour continuous light illumination stability test for DSSCs using Co(ttb)]2+/3+ resulted in a 10 % increase in the performance, whereas a 40 % decrease in performance was found for Co(bpy)3]2+/3+ electrolyte‐based DSSCs under the same conditions. These results demonstrate the great promise of Co(ttb)]2+/3+ complexes as redox mediators for efficient, cost‐effective, large‐scale DSSC devices. |
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| Keywords: | cobalt dye-sensitized solar cells photovoltaics redox mediator stability |
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