Two Different Chiral Groups Based Thermally Activated Delayed Fluorescence Materials for Circularly Polarized OLEDs

Area of Science:

• Organic electronics
• Materials science
• Photonics

Background:

• Circularly polarized organic light-emitting diodes (CP-OLEDs) are crucial for advanced 3D display technologies.
• Direct generation of circularly polarized luminescence (CPL) is key for efficient CP-OLEDs.

Purpose of the Study:

• To synthesize novel circularly polarized thermally activated delayed fluorescence (CP-TADF) enantiomers.
• To investigate the impact of chiral group configuration on CPL properties and device performance.

Main Methods:

• Synthesis of two pairs of CP-TADF enantiomers (RR/SS-ONCN and RS/SR-ONCN) by incorporating chiral groups into a dicyanobenzene unit.
• Characterization of CPL properties using dissymmetry photoluminescence factors (|g_PL|).
• Fabrication and testing of CP-OLED devices.

Main Results:

• Achieved CPL properties with |g_PL| values of 1.3×10^-3 and 2.0×10^-3 for RR/SS-ONCN and RS/SR-ONCN, respectively.
• Identical chiral group configurations in RR/SS-ONCN enhanced |g_PL| values, suggesting a stacking effect.
• CP-OLEDs demonstrated high external quantum efficiencies up to 21.9% and electroluminescence |g_EL| factors up to 1.0×10^-3.

Conclusions:

• The configuration of chiral groups significantly influences CPL performance in TADF materials.
• The developed CP-TADF enantiomers show great potential for high-performance 3D displays.
• Optimizing molecular design can lead to enhanced circularly polarized emission in organic devices.