Lignin-Based Temperature Phosphorescent Material Composites: Long Afterglow & Water Stability

Area of Science:

• Materials Science
• Organic Chemistry
• Nanotechnology

Background:

• Room-temperature phosphorescence (RTP) materials suffer from emission quenching in aqueous environments, limiting their practical applications.
• Lignin, a renewable biomass resource, offers potential for developing novel phosphorescent materials.

Purpose of the Study:

• To create ultralong and water-resistant RTP materials using lignin-derived carbon dots (CDs).
• To address the limitations of RTP materials in aqueous solutions for advanced applications like anticounterfeiting.

Main Methods:

• Selective depolymerization of lignin using a computationally guided deep eutectic solvent (DES) to produce carbon dots (CDs) with tailored surface chemistry.
• Immobilization of heteroatom-doped CDs within a rigid polyacrylamide (PAM) network for nanoscale rigidification.
• Introduction of a crystalline isophthalic acid (IPA) layer as a macroscopic protective barrier against quenchers.

Main Results:

• The hierarchical strategy resulted in RTP materials with an extended phosphorescence lifetime of 729 ms.
• A visible afterglow exceeding 6 seconds was achieved in aqueous solution, a novel outcome for lignin-based RTP systems.
• The composite demonstrated excellent stability in various solvents and significant potential for anticounterfeiting.

Conclusions:

• A multilevel rigidification and encapsulation strategy effectively enhances the water resistance and emission lifetime of lignin-derived RTP materials.
• The developed materials overcome key limitations of RTP in aqueous environments, opening avenues for practical applications.
• The study highlights the potential of lignin-based carbon dots for advanced functional materials and anticounterfeiting technologies.