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New Aggregation-Induced Delayed Fluorescence Luminogens With Through-Space Charge Transfer for Efficient Non-doped
Panpan Zhang1, Jiajie Zeng1, Jingjing Guo1
1State Key Laboratory of Luminescent Materials and Devices, Center for Aggregation-Induced Emission, South China University of Technology, Guangzhou, China.
Frontiers in Chemistry
|April 27, 2019
Summary
New luminogens with through-space conjugation exhibit aggregation-induced delayed fluorescence (AIDF), leading to efficient non-doped organic light-emitting diodes (OLEDs) with high quantum efficiency and low roll-off.
Area of Science:
- Materials Science
- Organic Chemistry
- Photophysics
Background:
- Developing efficient luminescent materials is crucial for advanced organic light-emitting diodes (OLEDs).
- Aggregation-induced delayed fluorescence (AIDF) offers a pathway to overcome efficiency limitations in solid-state emitters.
Purpose of the Study:
- To synthesize and characterize novel luminogens based on through-space conjugation for OLED applications.
- To investigate the structure-property relationships governing the aggregation-induced delayed fluorescence (AIDF) behavior.
Main Methods:
- Synthesis and characterization of donor-acceptor molecules bridged by hexaphenylbenzene (HPB).
- Systematic investigation of thermal stability, electrochemistry, crystal structure, electronic structure, and photophysical properties.
- Fabrication and testing of non-doped organic light-emitting diodes (OLEDs).
Main Results:
- Synthesized luminogens exhibit propeller-like alignment of phenyl rings in HPB, facilitating through-space charge transfer.
- Molecules show weak fluorescence in solution but strong fluorescence and significant delayed component in aggregates (AIDF).
- Neat films display high photoluminescence quantum yields (PLQY) and prominent delayed fluorescence.
- Non-doped OLEDs achieve a maximum external quantum efficiency of 12.7% with minimal efficiency roll-off (2.7% at 1,000 cd m⁻²).
Conclusions:
- Through-space charge transfer in AIDF molecules is a viable strategy for developing robust luminescent materials.
- These novel luminogens demonstrate excellent potential for high-performance, non-doped OLED applications.
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