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An Electrochemical Cholesteric Liquid Crystalline Device for Quick and Low-Voltage Color Modulation
Published on: February 27, 2019
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Chiral polymer hosts for circularly polarized electroluminescence devices
Jayeon Hong1, Sangsub Kim2, Gyurim Park1
1Division of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University Seoul 03760 Republic of Korea odds2@ewha.ac.kr.
Chemical Science
|July 14, 2021
Summary
Researchers developed new chiral polymer hosts for circularly polarized PLEDs. These hosts enhance chiroptical performance by inducing helical structures, leading to improved energy transfer and amplified electroluminescence dissymmetry factors.
Area of Science:
- Materials Science
- Polymer Chemistry
- Organic Electronics
- Photonics
Background:
- Circularly polarized luminescence (CP PLEDs) are crucial for photonic applications.
- Fabricating CP PLEDs necessitates chiral polymer hosts to create specific chiral environments.
- Existing chemical strategies for designing chiral polymer hosts are limited.
Purpose of the Study:
- To develop novel chiral polymer hosts for enhanced CP PLED applications.
- To investigate the chirality transfer from monomers to polymer chains.
- To evaluate the impact of chiral polymer hosts on dopant interaction and energy transfer.
Main Methods:
- Free-radical polymerization of 3-vinylcarbazole with a chiral N-alkyl unit.
- Electronic circular dichroism measurements to confirm chirality transfer.
- Fabrication and evaluation of multilayer CP PLED devices with phosphorescent dopants.
Main Results:
- Chiral polymer hosts were successfully synthesized, inducing preferred (P)-helical sense along the polymer backbone.
- Chirality transfer from chiral to achiral monomers was observed during polymerization.
- Chiral polymer hosts demonstrated diastereoselective interaction with dopants, leading to significantly enhanced Kuhn dissymmetry factors (g_abs).
- Faster energy transfer to phosphorescent dopants was observed in chiral hosts due to longer Förster radius and improved compatibility.
- Fabricated CP PLEDs exhibited electroluminescence dissymmetry factors (g_EL) of the order of 10^-4.
Conclusions:
- The developed chiral polymer hosts effectively amplify chiroptical performances in CP PLEDs.
- This work demonstrates a viable chemical strategy for designing advanced chiral polymer hosts.
- Further development in chiral polymer hosts holds promise for advanced photonic devices.
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