Radiative energy transfer enabling upconverted circularly polarized persistent luminescence for multilevel...

Area of Science:

• Materials Science
• Optoelectronics
• Photonics

Background:

• Optically active persistent luminescent materials offer unique polarization properties for anticounterfeiting.
• Developing upconverted circularly polarized persistent luminescence (UC-CPPL) materials presents significant fabrication challenges.
• Existing materials lack the integrated functionalities for advanced information encryption.

Purpose of the Study:

• To present an efficient strategy for constructing UC-CPPL materials.
• To achieve amplified circularly polarized persistent luminescence through chiral nematic liquid crystals.
• To enable sophisticated and secure information encryption using integrated optical properties.

Main Methods:

• Embedding upconversion nanoparticles (UCNPs) and phosphors into chiral nematic liquid crystals (N*LC).
• Utilizing a radiative energy transfer mechanism between UCNPs and phosphors upon near-infrared excitation.
• Tuning the photonic bandgap of the chiral N*LC to amplify luminescence dissymmetry.

Main Results:

• Successfully fabricated UC-CPPL materials via UCNPs and phosphors within N*LC.
• Achieved amplified UC-CPPL luminescence dissymmetry factor (g_UC-CPPL) up to approximately 0.6.
• Demonstrated integration of circularly polarized luminescence, persistent luminescence, and upconversion luminescence.

Conclusions:

• The developed UC-CPPL materials offer a promising platform for advanced anticounterfeiting applications.
• The integration of multiple optical properties enables sophisticated and secure information encryption.
• This approach facilitates controlled concealment and selective release of encrypted information with enhanced security.