American Chemical Society
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Bifurcation of Regeneration and Recombination in Dye-Sensitized Solar Cells via Electronic Manipulation of Tandem Cobalt Redox Shuttles

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journal contribution
posted on 2017-03-24, 00:00 authored by Josh Baillargeon, Yuling Xie, Thomas W. Hamann
A cobalt­(IV/III) redox shuttle, cobalt tris­(2-(p-tolyl)­pyridine), [Co­(ptpy)3]+/0, was synthesized and investigated for use in dye-sensitized solar cells, DSSCs. An incredibly fast self-exchange rate constant of (9.2 ± 3.9) × 108 M–1 s–1 was determined for [Co­(ptpy)3]+/0, making it an ideal candidate for dye regeneration. To avoid fast recombination and solubility limitations, we utilized a tandem electrolyte containing [Co­(ptpy)3]+/0 and cobalt tris­(2,2′-bipyridine), [Co­(bpy)3]3+/2+. An improved short circuit current density is achieved for DSSCs employing the tandem electrolyte, compared to electrolytes containing only [Co­(bpy)3]3+/2+, consistent with superior dye regeneration expected based on predictions using Marcus theory, which is also discussed.