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 language | English |
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Article number | 8033 |
Pages (from-to) | 8026-8033 |
Number of pages | 8 |
Journal | The journal of physical chemistry letters |
Volume | 11 |
Issue number | 19 |
Early online date | 2 Sept 2020 |
DOIs | |
Publication status | Published - 1 Oct 2020 |
Keywords
- Dyes and pigments
- Salts
- Self organization
- Monomers
- Aggregation