Thermodynamic Control over Molecular Aggregate Assembly Enables Tunable Excitonic Properties across the Visible and Near-Infrared

Arundhati P. Deshmukh, Austin D. Bailey, Leandra S. Forte, Xingyu Shen, Niklas Geue, Ellen M. Sletten, Justin R. Caram

Research output: Contribution to journalArticlepeer-review

Abstract

Specific molecular arrangements within H-/J-aggregates of cyanine dyes enable extraordinary photophysical properties, including long-range exciton delocalization, extreme blue/red shifts, and excitonic superradiance. Despite extensive literature on cyanine aggregates, design principles that drive the self-assembly to a preferred H- or J-aggregated state are unknown. We tune the thermodynamics of self-assembly via independent control of the solvent/nonsolvent ratio, ionic strength, or dye concentration, obtaining a broad range of conditions that predictably stabilize the monomer (H-/J-aggregate). Diffusion-ordered spectroscopy, cryo-electron microscopy, and atomic force microscopy together reveal a dynamic equilibrium between monomers, H-aggregated dimers, and extended J-aggregated 2D monolayers. We construct a model that predicts the equilibrium composition for a range of standard Gibbs free energies, providing a vast aggregation space which we access using the aforementioned solvation factors. We demonstrate the universality of this approach among several sheet-forming cyanine dyes with tunable absorptions spanning visible, near, and shortwave infrared wavelengths.
Original languageEnglish
Article number8033
Pages (from-to)8026-8033
Number of pages8
JournalThe journal of physical chemistry letters
Volume11
Issue number19
Early online date2 Sept 2020
DOIs
Publication statusPublished - 1 Oct 2020

Keywords

  • Dyes and pigments
  • Salts
  • Self organization
  • Monomers
  • Aggregation

Fingerprint

Dive into the research topics of 'Thermodynamic Control over Molecular Aggregate Assembly Enables Tunable Excitonic Properties across the Visible and Near-Infrared'. Together they form a unique fingerprint.

Cite this