Dye aggregation identified by vibrational coupling using 2D IR spectroscopy

Tracey A. Oudenhoven, Yongho Joo, Jennifer E. Laaser, Padma Gopalan, Martin T. Zanni

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

We report that a model dye, Re(CO)3(bypy)CO2H, aggregates into clusters on TiO2 nanoparticles regardless of our preparation conditions. Using two-dimensional infrared (2D IR) spectroscopy, we have identified characteristic frequencies of monomers, dimers, and trimers. A comparison of 2D IR spectra in solution versus those deposited on TiO2 shows that the propensity to dimerize in solution leads to higher dimer formation on TiO2, but that dimers are formed even if there are only monomers in solution. Aggregates cannot be washed off with standard protocols and are present even at submonolayer coverages. We observe cross peaks between aggregates of different sizes, primarily dimers and trimers, indicating that clusters consist of microdomains in close proximity. 2D IR spectroscopy is used to draw these conclusions from measurements of vibrational couplings, but if molecules are close enough to be vibrationally coupled, then they are also likely to be electronically coupled, which could alter charge transfer.

Original languageEnglish (US)
Article number212449
JournalJournal of Chemical Physics
Volume142
Issue number21
DOIs
StatePublished - Jun 7 2015

Fingerprint

Dive into the research topics of 'Dye aggregation identified by vibrational coupling using 2D IR spectroscopy'. Together they form a unique fingerprint.

Cite this