1421755-99-8Relevant articles and documents
Atomic level resolution of dye regeneration in the dye-sensitized solar cell
Robson, Kiyoshi C. D.,Hu, Ke,Meyer, Gerald J.,Berlinguette, Curtis P.
, p. 1961 - 1971 (2013/04/10)
Two donor-acceptor organic dyes have been synthesized that differ only by a two-heteroatom change from oxygen to sulfur within the donor unit. The two dyes, (E)-3-(5-(4-(bis(4-(hexyloxy)phenyl)amino)phenyl)thiophen-2-yl)-2- cyanoprop-2-enoic acid (Dye-O) and (E)-3-(5-(4-(bis(4-(hexylthio)phenyl)amino) phenyl)thiophen-2-yl)-2-cyanoprop-2-enoic acid) (Dye-S), were tested in solar cell devices employing both I3-/I--based and [Co(bpy)3]3+/2+ redox mediators. Power conversion efficiencies over 6% under simulated AM 1.5 illumination (1 Sun) were achieved in both electrolytes. Despite similar optical and redox properties for the two dyes, a consistently higher open-circuit voltage (Voc) was measured for Dye-S relative to Dye-O. The improved efficiency observed with Dye-S in an iodide redox mediator is against the commonly held view that sulfur atoms promote charge recombination attributed to inner-sphere interactions. Detailed mechanistic studies revealed that this is a consequence of a 25-fold enhancement of the regeneration rate constant that enhances the regeneration yield under open circuit conditions. The data show that a high short circuit photocurrent does not imply optimal regeneration efficiency as is often assumed.
