White Fluorescent Organic Light-Emitting Diodes with 100% Power Conversion

Area of Science:

• Materials Science
• Organic Electronics
• Photophysics

Background:

• Energy-efficient lighting is crucial for reducing carbon emissions.
• White organic light-emitting diodes (OLEDs) offer theoretical 100% internal quantum efficiency.
• Harvesting triplet excitons in pure organic fluorescent materials remains a challenge.

Purpose of the Study:

• To develop a highly efficient white fluorescent OLED.
• To overcome the limitations of triplet exciton harvesting in organic emitters.
• To achieve high external quantum efficiency (EQE) and power efficiency (PE).

Main Methods:

• Fabrication of a white fluorescent OLED using a single emissive layer.
• Employing blue thermally activated delayed fluorescent (TADF) emitters to sensitize a yellow fluorescent emitter.
• Utilizing transient photoluminescence and electroluminescence analyses.

Main Results:

• Achieved an external quantum efficiency (EQE) of 30.7%.
• Attained a power efficiency (PE) of 120.2 lm W⁻¹.
• Demonstrated complete triplet exciton conversion to singlet excitons via blue TADF emitters, suppressing triplet quenching.

Conclusions:

• The developed white fluorescent OLED effectively harvests triplet excitons for light emission.
• The strategy of using blue TADF emitters to sensitize yellow fluorescent emitters enables 100% power conversion efficiency.
• This work provides a viable pathway towards highly efficient and energy-saving OLED lighting solutions.