Thermally Activated Delayed Fluorescence Enabled by Reversed Conformational Distortion for Blue Emitters

Area of Science:

• Organic Chemistry
• Materials Science
• Photophysics

Background:

• Thermally activated delayed fluorescence (TADF) is crucial for efficient organic light-emitting diodes (OLEDs).
• Developing purely organic blue emitters with high performance remains a challenge.

Purpose of the Study:

• To introduce a general strategy for TADF using molecular reversed conformational distortion.
• To design and synthesize a novel purely organic blue light-emitting material.

Main Methods:

• Molecular design and synthesis of a model compound (BNNIO).
• Transient spectroscopy to determine the rate constant of reverse intersystem crossing.
• Photoluminescence spectroscopy to measure quantum yield and lifetime.

Main Results:

• Successfully synthesized the BNNIO compound.
• Achieved a high rate constant of reverse intersystem crossing (2.34 × 10^4 s^-1).
• Observed TADF emission with 90.72% photoluminescence quantum yield and 84.76 μs lifetime at 415 nm.

Conclusions:

• The molecular reversed conformational distortion strategy is effective for developing purely organic TADF materials.
• BNNIO demonstrates excellent performance as a blue light emitter.
• This work opens new avenues for designing novel organic blue light-emitting materials.