Maximizing regeneration and minimizing recombination rates at dye–semiconductor interfaces is crucial for the realization of efficient dye-sensitized solar and photoelectrosynthesis cells. Previously it has been shown that simply coordinating the metal ion to the nonsurface bound carboxylate groups of a dye molecule can slow recombination rates and increase open-circuit voltages. However, it was unclear if the additional steric effects or charge of the metal ion were the cause of this behavior. Here we use three different redox mediators, (1) I–/I3 –, (2) [tris(1,10-phenanthroline)cobalt]3+/2+, and (3) [Co(4,4′,4″-tritert-butyl-2,2′:6′,2″-terpyridine)(NCS)3]0/1– to elucidate the role, if any, of electrostatic interactions between the coordinated metal ion and mediator in dictating these interfacial electron transfer events. Using a combination of spectroscopy, electrochemistry, and solar cell measurements, we demonstrate that while electrostatic interactions may influence dye regeneration rates, for example, increased steric bulk of the metal ion between TiO2(e–) and the oxidized mediator likely has a stronger influence on the overall device performance. Additionally, electrochemical impedance spectroscopy and intensity dependent measurements suggest that the coordination of the metal ion can slow diffusion of the mediators within the mesoporous oxide which could have implications for the use of multilayer assemblies in dye-sensitized devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.