Visible-Light-Excited Ultralong Organic Phosphorescence by Manipulating Intermolecular Interactions

Area of Science:

• Materials Science
• Organic Chemistry
• Photophysics

Background:

• Visible light is a preferred excitation source over UV due to availability and safety.
• Achieving ultralong organic phosphorescence (UOP) with visible light excitation is challenging.

Purpose of the Study:

• To develop a method for bright UOP using visible light excitation.
• To tune molecular packing in the solid state for enhanced phosphorescence.

Main Methods:

• Incorporation of halogen atoms to induce redshift in excitation spectra.
• Utilizing H-aggregation to stabilize the excited triplet state.
• Solid-state molecular packing under visible light irradiation.

Main Results:

• Achieved bright UOP with high phosphorescence efficiency (8.3%) and long lifetime (0.84 s).
• Observed visible-light-driven UOP lasting 104 s with a brightness of 0.32 mcd m⁻².
• Demonstrated dual data encryption and decryption using the UOP materials.

Conclusions:

• A concise chemical approach enables bright, visible-light-excited UOP via solid-state tuning.
• The developed metal-free UOP materials show promise for data security and bioimaging applications.