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Updated: Jul 7, 2025
Production and Characterization of Vacuum Deposited Organic Light Emitting Diodes
Published on: November 16, 2018
Liquid-crystalline circularly polarised TADF emitters for high-efficiency, solution-processable organic
Binghong He1, Qihang Zhong1, Qiwei Dong1
1School of Materials Science & Engineering, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, Changzhou University, Changzhou 213164, P. R. China. qiji830404@hotmail.com.
This study introduces novel liquid-crystalline circularly polarised thermally activated delayed fluorescence (CP-TADF) molecules. These molecules achieve high luminescence asymmetry factors (g_lum) and emission efficiency in organic light-emitting diodes (OLEDs).
Area of Science:
- Organic electronics
- Materials science
- Photophysics
Background:
- Achieving high emission efficiency and luminescence asymmetry (g_lum) in circularly polarised thermally activated delayed fluorescence (CP-TADF) molecules is challenging.
- Liquid crystals offer inherent molecular order that can be exploited to enhance optical properties.
Purpose of the Study:
- To design and synthesise novel liquid-crystalline CP-TADF molecules for high g_lum.
- To investigate the photophysical properties and device performance of these new materials.
Main Methods:
- Synthesis of chiral dinaphthol-based CP-TADF molecules (R/S-4) incorporating mesogenic moieties.
- Characterisation of emission, electronic circular dichroism (CD), and circular polarisation luminescence (CPL) in thin films.
- Fabrication of solution-processed organic light-emitting diodes (OLEDs) using R/S-4 as dopants and CzAcSF as a sensitiser.
Main Results:
- Synthesised enantiomers (R/S-4) exhibit intense emission around 520 nm with clear TADF and liquid-crystalline characteristics.
- Thin films of R/S-4 display symmetrical CD and CPL signals, achieving a g_lum of 0.11.
- OLEDs fabricated with R/S-4 dopants achieved a maximum external quantum efficiency of 21.2%.
Conclusions:
- Liquid-crystalline order provides a viable strategy for realising large g_lum in CP-TADF materials.
- The developed CP-TADF molecules demonstrate potential for efficient circularly polarised light emission in OLEDs.
- This work presents a novel approach for enhancing g_lum in CP-TADF systems.
