Aromatic-Imide-Based Thermally Activated Delayed Fluorescence Materials for Highly Efficient Organic Light-Emitting...

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• Thermally activated delayed fluorescence (TADF) materials are crucial for efficient organic light-emitting diodes (OLEDs).
• Designing novel TADF emitters with high thermal stability and quantum yields remains a key challenge in optoelectronics.

Purpose of the Study:

• To synthesize novel aromatic-imide-based TADF materials with a twisted donor-acceptor-donor (D-A-D) structure.
• To investigate the photophysical properties and thermal stability of the synthesized TADF materials.
• To evaluate the performance of these materials as dopants in OLED devices.

Main Methods:

• Efficient synthesis of aromatic-imide-based D-A-D compounds.
• Characterization of thermal stability using thermogravimetric analysis.
• Photophysical studies including photoluminescence quantum yield (PLQY) measurements.
• Transient photoluminescence (PL) spectroscopy to determine the small energy gap between singlet and triplet excited states (ΔE_ST).
• Fabrication and testing of OLED devices using the synthesized TADF materials as dopants.

Main Results:

• Successfully synthesized novel aromatic-imide-based TADF materials with a twisted D-A-D skeleton.
• Achieved excellent thermal stability and high photoluminescence quantum yields.
• Demonstrated small ΔE_ST values (<0.1 eV) and temperature-dependent delayed PL components, confirming efficient TADF properties.
• OLED devices doped with AI-Cz and AI-TBCz achieved outstanding external quantum efficiencies of up to 23.2% and 21.1%, respectively.

Conclusions:

• The developed aromatic-imide-based TADF materials exhibit promising properties for high-performance OLED applications.
• The twisted D-A-D structure is effective in achieving efficient TADF and high device performance.
• These materials represent a significant advancement in the field of organic optoelectronics.