Achieving High-Performance Multi-Resonance Thermally Activated Delayed Fluorescence (MR-TADF) Blue Emitter Using...

Area of Science:

• Materials Science
• Organic Electronics
• Photophysics

Background:

• Multi-resonance thermally activated delayed fluorescence (MR-TADF) materials are crucial for ultra-high-definition displays due to their narrowband emission.
• Challenges in MR-TADF development include limited chemical modification and significant efficiency roll-off.

Purpose of the Study:

• To develop novel MR-TADF materials with improved efficiency and suppressed roll-off.
• To investigate the impact of benzothiophene (BZT) heterocyclic fusion on MR-TADF emitter properties.

Main Methods:

• Chemical modification of single-boron and dual-boron MR-TADF emitters using a BZT heterocyclic fusion strategy.
• Experimental characterization and theoretical analysis of the photophysical properties of the new derivatives (SS-B and SS-2B).

Main Results:

• The BZT fusion strategy yielded two new MR-TADF derivatives, SS-B and SS-2B.
• Narrow emission spectra with full width at half maximum (FWHM) of 26 nm (SS-B) and 29 nm (SS-2B).
• High maximum external quantum efficiencies (EQEmax) of 34.34% (SS-B) and 37.23% (SS-2B), with SS-2B showing only 4.9% roll-off at 100 cd·m⁻².

Conclusions:

• The BZT heterocyclic fusion is an effective strategy for enhancing the electroluminescence performance of MR-TADF materials.
• The developed materials enable high-efficiency, high-color-purity blue OLEDs with reduced efficiency roll-off.
• This study deepens the understanding of boron/nitrogen (B/N) molecular systems and offers a new pathway for advanced OLED development.