Engineering Tunable Ratiometric Dual Emission in Single Emitter-based Amorphous Systems.

Area of Science:

• Materials Science
• Organic Chemistry
• Photophysics

Background:

• Multi-emissive molecular emitters are crucial for advanced applications but typically rely on specific molecular arrangements.
• Achieving complex luminescence in amorphous systems, which lack ordered structures, presents a significant challenge.

Purpose of the Study:

• To present a general strategy for designing molecular emitters with dual fluorescence and phosphorescence properties.
• To demonstrate tunable luminescence in both crystalline and amorphous solid states.
• To explore applications in high-security anti-counterfeiting and functional materials.

Main Methods:

• Designing molecular emitters by balancing molecular rigidity and the singlet-triplet (S1-T1) energy gap.
• Fabricating amorphous films using polymethyl methacrylate (PMMA) to enable in situ regulation of dual-emissive characteristics.
• Utilizing ratiometric control of phosphorescence with stable fluorescence as an internal reference for color tuning.

Main Results:

• Successfully achieved fluorescence-phosphorescence dual-emission in various solid forms, including amorphous systems.
• Demonstrated highly controllable luminescent color tuning from yellow to blue, including white emission, via external stimuli.
• Observed persistent luminescence, enabling unique optical information combinations for ultrahigh-security anti-counterfeiting.

Conclusions:

• Introduced a concept to decouple complex luminescent properties from crystal form and molecular conformation dependence.
• Developed a versatile strategy for designing functional luminescent materials with tunable properties.
• Highlighted the potential for advanced anti-counterfeiting and optical information storage applications.