Tubular J-aggregates of cyanine dyes in the near-infrared

Austin Bailey; Arundhati Deshmukh; Timothy Atallah; Ulugbek Barotov; Monica Pengshung; Ellen Sletten; Justin Caram

doi:10.26434/chemrxiv-2021-rjmvz

Materials Chemistry

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Tubular J-aggregates of cyanine dyes in the near-infrared

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Working Paper

Austin Bailey University of California, Los Angeles ,
Arundhati Deshmukh University of California, Los Angeles ,
Timothy Atallah Denison University ,
Ulugbek Barotov Massachusetts Institute of Technology ,
Monica Pengshung University of California, Los Angeles ,
Ellen Sletten University of California, Los Angeles ,
Justin Caram University of California, Los Angeles

Abstract

Developing improved organic infrared emitters has wide-ranging applicability in fields such as bioimaging or energy harvesting. We synthesize redshifted analogues of C8S3, a well-known cyanine dye that self assembles into tubular aggregates which have attracted widespread attention as artificial photosynthetic complexes. Despite the elongated dye structure, the new pentamethine dyes retain their tubular self-assembly and emit at near-infrared wavelengths. Cryo-electron microscopy and detailed photophysical characterization of the new aggregates reveal similar absorption lineshapes with ~100 nm of redshift, as well as supramolecular morphologies that resemble their trimethine counterparts; the pentamethine aggregates generally show more disorder and decreased superradiance, suggesting that more ordered structures yield more robust photophysical properties. These results provide design principles of superradiant organic emitters, expand the chemical space of near-infrared aggregates, and introduce two additional wavelength-specific antennae as model systems for study.