Red Room Temperature Phosphorescence from Lignin

Area of Science:

• Materials Science
• Organic Chemistry
• Sustainable Chemistry

Background:

• Developing red room-temperature phosphorescence (RTP) materials from sustainable sources is a significant challenge.
• Lignin, a renewable biopolymer, offers potential but requires functionalization for advanced optical properties.

Purpose of the Study:

• To synthesize novel red RTP materials from lignin.
• To investigate the impact of chemical modification on lignin's phosphorescent properties.
• To explore the potential of these materials in applications like anti-counterfeiting.

Main Methods:

• Covalent modification of lignin with Upy (1-(6-isocyanatohexyl)-3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl) urea) to create Lig-Upy.
• Characterization of Lig-Upy's photophysical properties, including RTP emission wavelength and lifetime.
• Embedding Lig-Upy into different matrices (PVA, MTM) to study matrix-dependent property variations.

Main Results:

• Lig-Upy demonstrated red RTP centered at 625 nm with a long lifetime of 24.2 ms.
• The Upy modification enhanced intermolecular interactions and reduced energy gaps in lignin.
• Embedding Lig-Upy in PVA and MTM matrices resulted in tunable RTP wavelengths and lifetimes.
• Developed time-dependent phosphorescent color (TDPC) materials from Lig-Upy.

Conclusions:

• Lignin can be effectively functionalized to produce sustainable red RTP materials.
• The tunable phosphorescence of Lig-Upy opens avenues for advanced optical applications.
• TDPC materials derived from Lig-Upy show promise for visual decoration, information encryption, and anti-counterfeiting.