"Core-Shell" Wave Function Modulation in Organic Narrowband Emitters.

Area of Science:

• Materials Science
• Organic Electronics
• Photophysics

Background:

• Efficient and stable red-green-blue (RGB) primary luminescence is essential for advanced display technologies.
• Multiple-resonance (MR) effects in organic emitters offer narrow spectral widths but face challenges in color tuning and purity.

Purpose of the Study:

• To develop a strategy for wide-range color tuning in MR emitters without sacrificing color purity.
• To engineer a novel organic emitter with enhanced stability for display applications.

Main Methods:

• Proposed a "core-shell" molecular design utilizing electronic donor/acceptor modulation within a boron/nitrogen (B/N) MR framework.
• Employed intramolecular charge transfer to tune emission wavelengths.
• Synthesized and characterized a pure-red emitter by doping a single boron atom into a deep-blue MR framework.

Main Results:

• Achieved a significant bathochromic shift from 447 nm to 624 nm (0.8 eV) with a narrow spectral width of 0.10 eV.
• Demonstrated superb electroluminescent stability in organic light-emitting diodes (OLEDs) using thermally activated delayed fluorescence (TADF) molecules, with LT99 > 400 h at 1000 cd m⁻².
• Attained commercial-level performance without the need for phosphors.

Conclusions:

• The "core-shell" modulation strategy effectively enables rational color tuning and maintains narrow spectral widths in MR emitters.
• The developed pure-red emitter exhibits promising potential for high-performance, stable, and phosphor-free OLED displays.