Tetracoordinate Boron-Based Multifunctional Chiral Thermally Activated Delayed Fluorescence Emitters

Area of Science:

• Materials Science
• Organic Electronics
• Photochemistry

Background:

• Organic light-emitting diodes (OLEDs) are crucial for displays and lighting.
• Near-infrared (NIR) OLEDs face efficiency challenges due to non-radiative recombination.
• Purely organic emitters are sought for improved NIR-OLED performance.

Purpose of the Study:

• To design and synthesize novel thermally activated delayed fluorescence (TADF) enantiomers for NIR-OLEDs.
• To investigate the photophysical properties and electroluminescent performance of new organic emitters.
• To enhance the efficiency and stability of solution-processed NIR-OLEDs.

Main Methods:

• Design and synthesis of two pairs of tetracoordinate boron-based TADF enantiomers (R/S-DOBP and R/S-HDOBP).
• Characterization of photoluminescence quantum yields, reverse intersystem crossing, and electroluminescence.
• Fabrication and testing of nondoped, solution-processed NIR-OLED devices.

Main Results:

• The synthesized TADF emitters exhibit aggregation-induced emission, circularly polarized luminescence, and mechanochromism.
• High photoluminescence quantum yields and efficient reverse intersystem crossing were observed in neat films.
• Nondoped NIR-OLEDs demonstrated efficient NIR emission (716 nm) with a 1.9% external quantum efficiency and 86% exciton utilization efficiency.

Conclusions:

• The developed TADF enantiomers are highly promising for efficient, solution-processed NIR-OLEDs.
• These materials overcome key limitations of traditional organic emitters in the NIR spectrum.
• The study presents a significant advancement in the field of organic optoelectronics.