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Updated: Feb 26, 2026
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Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
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Disordered light-harvesting aggregates can host functional vibronic couplings at room temperature
Asha S Thomas1, Camelia Roy1, Indranil Roy1
1Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore, Karnataka, India.
Nature Communications
|February 24, 2026
Summary
Functional vibronic couplings in photosynthetic aggregates are confirmed at room temperature. This discovery in porphyrin nanotubes reveals how disorder enhances energy transfer, crucial for artificial photosynthesis.
Area of Science:
- Biophysics
- Materials Science
- Quantum Chemistry
Background:
- Photosynthesis utilizes chlorophyll-like molecules for efficient energy transfer.
- Cryogenic studies suggest coupled vibrational-electronic (vibronic) states are key.
- It remains unclear if these vibronic states persist in large aggregates at physiological temperatures.
Purpose of the Study:
- To investigate the presence and role of vibronic couplings in photosynthetic aggregates at room temperature.
- To explore energy transfer mechanisms in artificial systems mimicking natural photosynthesis.
Main Methods:
- Time-resolved optical spectroscopy was employed on porphyrin nanotubes.
- Polarization control was used to selectively probe coupled Qx-Qy states.
- Computational modeling was performed to understand the role of disorder.
Main Results:
- Observed early-time cross peaks between electronic states, indicating vibronic coupling.
- Demonstrated survival of quantum beats with anisotropic amplitude at room temperature.
- Calculations showed that energetic disorder significantly enhances intraband vibronic couplings.
Conclusions:
- Functional vibronic couplings exist in photosynthetic aggregates at physiological temperatures.
- Disorder is a critical factor in enhancing vibronic couplings within the Q band.
- Understanding these principles could guide the design of efficient artificial photosynthetic systems.
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