Facile Synthetic Access Towards Sulfur- and Selenium-Functionalized Boron-Based Multiresonance TADF Emitters

Area of Science:

• Materials Science
• Organic Electronics
• Photochemistry

Background:

• Thermally activated delayed fluorescence (TADF) materials are essential for efficient organic light-emitting diodes (OLEDs).
• High photoluminescence quantum yields and fast reverse intersystem crossing (RISC) are key performance metrics for TADF emitters.
• Triaryl boranes with multiple resonance (MR) effects are a promising class of TADF materials, but their efficiency depends on small singlet-triplet energy gaps and large RISC rate constants.

Purpose of the Study:

• To investigate the incorporation of heavy elements (sulfur and selenium) into MR-TADF emitters to enhance RISC rates via spin-orbit coupling (SOC).
• To develop an alternative synthetic strategy for producing sulfur- and selenium-doped 5,9-X2-13b-boranaphtho[3,2,1-de]anthracene (X-B-X) scaffold materials.

Main Methods:

• Development of a novel synthetic route for incorporating sulfur (S) and selenium (Se) into the X-B-X scaffold.
• Characterization of the synthesized S- and Se-doped MR-TADF materials.

Main Results:

• The new synthetic method successfully produced highly sought-after sulfur- and selenium-doped X-B-X materials.
• The synthesized materials were obtained with high yield and purity.
• This overcomes previous difficulties in incorporating these heavy elements into the MR-TADF scaffold.

Conclusions:

• The developed synthetic strategy provides an efficient pathway to novel S- and Se-doped MR-TADF materials.
• These materials hold significant potential for advancing the performance of narrowband-emissive OLEDs.
• The findings pave the way for exploring heavy-element incorporation in TADF emitters for accelerated RISC.