Multimode-Responsive Luminescence of Er³⁺ Single-Activated CaF₂ Phosphor for Advanced Information Encryption

Area of Science:

• Materials Science
• Optics
• Nanotechnology

Background:

• Current optical anticounterfeiting methods often rely on light or heat, limiting practical flexibility.
• Multimode luminescence is crucial for advanced anticounterfeiting and information encryption.

Purpose of the Study:

• To prepare novel Er3+ single-doped CaF2 phosphors with multi-stimuli-responsive luminescence.
• To explore their potential for flexible anticounterfeiting and information encryption applications.

Main Methods:

• Synthesis of Er3+ single-doped CaF2 phosphors.
• Characterization of photoluminescence (PL) and up-conversion (UC) luminescence.
• Investigation of mechano-luminescence induced by contact electrification with PDMS polymers.

Main Results:

• The CaF2:Er3+ phosphor demonstrated green photoluminescence and color-tunable up-conversion luminescence (red to green).
• Mechano-luminescence was observed, showing a green emission response to mechanical stimuli via contact electrification.
• The material exhibited cross-relaxation of Er3+ ions, contributing to tunable luminescence.

Conclusions:

• Successfully prepared CaF2:Er3+ phosphors exhibit multi-stimuli-responsive luminescence (light, heat, mechanical).
• These phosphors offer a flexible platform for advanced anticounterfeiting and information encryption schemes.
• The findings expand the application scope of optical materials in secure information technologies.