Constructing High-Efficiency and Stable Hyperfluorescence Blue OLEDs via TADF Sensitizers with Very Short Delayed...

Area of Science:

• Materials Science
• Organic Electronics
• Photophysics

Background:

• Hyperfluorescence blue organic light-emitting diodes (OLEDs) offer high efficiency and color purity.
• Developing blue thermally activated delayed fluorescence (TADF) sensitizers with a high reverse intersystem crossing rate (k_RISC > 10⁷ s^-1) is a significant challenge.

Purpose of the Study:

• To design and synthesize a novel blue TADF sensitizer with an enhanced k_RISC.
• To fabricate and characterize a hyperfluorescence blue OLED device using the developed TADF sensitizer.

Main Methods:

• Molecular design by regulating excited state energy levels and enhancing spin-orbit coupling (SOC).
• Fabrication of a hyperfluorescence device by doping with v-DABNA.
• Characterization of device performance, including external quantum efficiency (EQE) and operational lifetime.

Main Results:

• A blue TADF sensitizer with a k_RISC of 9.71 × 10⁶ s^-1 was successfully designed.
• The fabricated hyperfluorescence device achieved a maximum EQE of 31.0%.
• The device demonstrated a long operational lifetime of 175.4 hours.

Conclusions:

• The designed blue TADF sensitizer significantly contributes to achieving high-performance blue hyperfluorescence OLEDs.
• The study highlights the critical role of k_RISC in developing efficient blue TADF sensitizers.
• This work provides a pathway for future design of advanced blue TADF sensitizers and hyperfluorescence devices.