Document Type
Article
Publication Date
3-31-2022
Abstract
Molecular excitons, which propagate spatially via electronic energy transfer, are central to numerous applications including light harvesting, organic optoelectronics, and nanoscale computing; they may also benefit applications such as photothermal therapy and photoacoustic imaging through the local generation of heat via rapid excited-state quenching. Here we show how to tune between energy transfer and quenching for heterodimers of the same pair of cyanine dyes by altering their spatial configuration on a DNA template. We assemble “transverse” and “adjacent” heterodimers of Cy5 and Cy5.5 using DNA Holliday junctions. We find that the transverse heterodimers exhibit optical properties consistent with excitonically interacting dyes and fluorescence quenching, while the adjacent heterodimers exhibit optical properties consistent with nonexcitonically interacting dyes and disproportionately large Cy5.5 emission, suggestive of energy transfer between dyes. We use transient absorption spectroscopy to show that quenching in the transverse heterodimer occurs via rapid nonradiative decay to the ground state (∼31 ps) and that in the adjacent heterodimer rapid energy transfer from Cy5 to Cy5.5 (∼420 fs) is followed by Cy5.5 excited-state relaxation (∼700 ps). Accessing such drastically different photophysics, which may be tuned on demand for different target applications, highlights the utility of DNA as a template for dye aggregation.
Copyright Statement
This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. This document was originally published in The Journal of Physical Chemistry Letters by the American Chemical Society. Copyright restrictions may apply. https://doi.org/10.1021/acs.jpclett.2c00017
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Publication Information
Chowdhury, Azhad U.; Díaz, Sebastián A.; Huff, Jonathan S.; Barclay, Matthew S.; Chiriboga, Matthew; Ellis, Gregory A.; . . . and Pensack, Ryan D. (2022). "Tuning Between Quenching and Energy Transfer in DNA-Templated Heterodimer Aggregates". The Journal of Physical Chemistry Letters, 13(12), 2782-2791. https://doi.org/10.1021/acs.jpclett.2c00017
Comments
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