Color-Tunable All-Fluorescent White Organic Light-Emitting Diodes with a High External Quantum Efficiency Over 30%...

Area of Science:

• Materials Science
• Organic Electronics
• Photophysics

Background:

• White organic light-emitting diodes (WOLEDs) are crucial for next-generation displays and lighting.
• Thermally activated delayed-fluorescence (TADF) emitters offer potential for high-efficiency WOLEDs but face performance limitations.

Purpose of the Study:

• To develop an advanced double-emissive-layer device architecture for WOLEDs.
• To improve efficiency, color tunability, and operational stability of TADF-based WOLEDs.

Main Methods:

• Proposed a double-emissive-layer device architecture.
• Incorporated hole-trapping TADF-sensitized emissions.
• Investigated recombination zone shift and exciton emission dynamics.

Main Results:

• Achieved significant shifts in Commission Internationale de l'Eclairage (CIE) coordinates and correlated color temperatures.
• Demonstrated a maximum external quantum efficiency (EQE) of 30.7%, exceeding 25% over a wide luminance range.
• Extended LT80 lifetime to over 20,000 hours at 100 cd m⁻².

Conclusions:

• The proposed architecture enables efficient hole-trapping and TADF-sensitized emission.
• This work establishes a new benchmark for all-fluorescent WOLEDs with EQE exceeding 30%.