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Updated: May 31, 2025
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Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
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Dynamics of Pyrene Excimer in a Cholesteryl-Based Supramolecular Host Matrix
Shubham Verma1, Gargee Roy2, Nikumoni Doley1
1Spectroscopy and Dynamics Visualization Laboratory, Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhauri, Bhopal, 462066, Madhya Pradesh, India.
Summary
This study developed a cost-effective method to prevent luminescence loss in solid-state materials by encapsulating pyrene within a supramolecular gel. This approach enhances brightness and performance in displays by mitigating aggregation-caused quenching (ACQ).
Area of Science:
- Supramolecular Chemistry
- Materials Science
- Photophysics
Background:
- Aggregation-caused quenching (ACQ) significantly reduces luminescence efficiency in solid-state applications.
- Developing effective strategies to mitigate ACQ is crucial for enhancing material performance in displays and sensors.
- Low molecular weight gelators offer a promising platform for controlling molecular aggregation and luminescence properties.
Purpose of the Study:
- To present a cost-effective method for mitigating ACQ in pyrene by co-assembling it within a novel low molecular weight gelator.
- To investigate the exciton dynamics and monomer-excimer transition of pyrene in solution, powder, and xerogel phases.
- To understand how the supramolecular host environment influences the photophysical behavior of pyrene.
Main Methods:
- Synthesis of a low molecular weight gelator from cholesteryl chloroformate and pentaerythritol.
- Co-assembly of pyrene within the synthesized supramolecular gelator.
- Characterization using steady-state and time-resolved spectroscopic techniques, including time-resolved emission spectra (TRES) and time-resolved area-normalized emission spectra (TRANES).
Main Results:
- The synthesized gelator effectively encapsulated pyrene, mitigating ACQ in the solid-state.
- Spectroscopic analysis revealed distinct monomer-to-excimer transition dynamics in solution (single step), powder (two isoemissive points), and xerogel (three isoemissive points) phases.
- The solid matrix of the xerogel exhibited a complex excimer formation pathway with multiple intermediate states.
Conclusions:
- Encapsulation of pyrene within a supramolecular host is an effective strategy to overcome ACQ in solid-state materials.
- The dynamics of excimer formation are highly dependent on the phase and the nature of the solid matrix.
- This work provides insights into controlling luminescence properties through supramolecular self-assembly for advanced material applications.
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