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Spectroscopic detection of halogen bonding resolves dye regeneration in the dye-sensitized solar cell

TitleSpectroscopic detection of halogen bonding resolves dye regeneration in the dye-sensitized solar cell
Publication TypeJournal Article
Year of Publication2017
AuthorsParlane, FGL, Mustoe, C, Kellett, CW, Simon, SJ, Swords, WB, Meyer, GJ, Kennepohl, P, Berlinguette, CP
JournalNature Communications
Volume8
Pagination1761
ISSN2041-1723
Abstract

The interactions between a surface-adsorbed dye and a soluble redox-active electrolyte species in the dye-sensitized solar cell has a significant impact on the rate of regeneration of photo-oxidized dye molecules and open-circuit voltage of the device. Dyes must therefore be designed to encourage these interfacial interactions, but experimentally resolving how such weak interactions affect electron transfer is challenging. Herein, we use X-ray absorption spectroscopy to confirm halogen bonding can exist at the dye-electrolyte interface. Using a known series of triphenylamine-based dyes bearing halogen substituents geometrically positioned for reaction with halides in solution, halogen bonding was detected only in cases where brominated and iodinated dyes were photo-oxidized. This result implies that weak intermolecular interactions between photo-oxidized dyes and the electrolyte can impact device photovoltages. This result was unexpected considering the low concentration of oxidized dyes (less than 1 in 100,000) under full solar illumination.

URLhttps://doi.org/10.1038/s41467-017-01726-7
DOI10.1038/s41467-017-01726-7