Tuning triplet excitons and dynamic afterglow based on host-guest doping

Area of Science:

• Materials Science
• Organic Electronics
• Photophysics

Background:

• Traditional long afterglow materials suffer from homogenization and singularity issues.
• Developing persistent dual-band afterglow materials is crucial for advanced applications.
• Thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) offer tunable emission properties.

Purpose of the Study:

• To design and synthesize novel persistent dual-band afterglow materials.
• To investigate the photophysical properties of TADF and RTP in new material systems.
• To explore potential applications in data encryption and anti-counterfeiting.

Main Methods:

• Synthesis of six aryl acetonitrile (CBM) and aryl dicyanoaniline (AMBT) derivatives.
• Fabrication of host-guest doping systems using CBM and AMBT compounds.
• Characterization of photoluminescence, afterglow lifetimes, and quantum yields.

Main Results:

• The m-CBM/p-AMBT system exhibited dual-band TADF (540 ms) and RTP (721 ms) with over 8 s afterglow.
• Triple-band emissions (TADF, unimolecular, and aggregated AMBT) were observed in CBM/AMBT doping systems.
• A PMMA film doped with o-AMBT showed high quantum yields (ΦFL=0.17, ΦT=0.17, ΦP=0.23) and long lifetimes (TADF=606 ms, RTP=727 ms, afterglow=10 s).

Conclusions:

• Host-sensitized guest emission mechanism explains the TADF and RTP in CBM/AMBT systems.
• AMBT derivatives show enhanced TADF/RTP intensity ratios in PMMA films compared to CBM systems.
• The developed materials enable data encryption and dynamic anti-counterfeiting patterns based on distinct emission properties.