Bridging the gap between H- and J-aggregates: Classification and supramolecular tunability for excitonic band structures in two-dimensional molecular aggregates
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021401_1_online.pdf
Description
Published version
Size
3.12 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Deshmukh, Arundhati P
Geue, Niklas
Bradbury, Nadine C
Atallah, Timothy L
Chuang, Chern
Pengshung, Monica
Cao, Jianshu
Sletten, Ellen M
Neuhauser, Daniel
Caram, Justin R
Date Issued
June 23, 2022
Journal
Chemical Physics Reviews
Publisher
AIP Publishing
Citation
Arundhati P. Deshmukh, Niklas Geue, Nadine C. Bradbury, Timothy L. Atallah, Chern Chuang, Monica Pengshung, Jianshu Cao, Ellen M. Sletten, Daniel Neuhauser, Justin R. Caram; Bridging the gap between H- and J-aggregates: Classification and supramolecular tunability for excitonic band structures in two-dimensional molecular aggregates. Chem. Phys. Rev. 1 June 2022; 3 (2): 021401.
Version
Final published version
Abstract
Molecular aggregates with long-range excitonic couplings have drastically different photophysical properties compared to their monomer counterparts. From Kasha's model for one-dimensional systems, positive or negative excitonic couplings lead to blue or red-shifted optical spectra with respect to the monomers, labeled H-and J-aggregates, respectively. The overall excitonic couplings in higher dimensional systems are much more complicated and cannot be simply classified from their spectral shifts alone. Here, we provide a unified classification for extended 2D aggregates using temperature dependent peak shifts, thermal broadening, and quantum yields. We discuss the examples of six 2D aggregates with J-like absorption spectra but quite drastic changes in quantum yields and superradiance. We find the origin of the differences is, in fact, a different excitonic band structure where the bright state is lower energy than the monomer but still away from the band edge. We call this an “I-aggregate.” Our results provide a description of the complex excitonic behaviors that cannot be explained solely on Kasha's model. Furthermore, such properties can be tuned with the packing geometries within the aggregates providing supramolecular pathways for controlling them. This will allow for precise optimizations of aggregate properties in their applications across the areas of optoelectronics, photonics, excitonic energy transfer, and shortwave infrared technologies.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
10.1063/5.0094451
