Long Persistent Luminescence in Cu²⁺-Doped SrGa₂Ge₂O₈ for Information Storage and Encryption

Area of Science:

• Materials Science
• Solid-State Chemistry
• Optoelectronics

Background:

• Current optical information storage relies on long persistent luminescent (PersL) materials with limited security due to single response modes.
• Rare earth-doped PersL materials are costly, hindering widespread adoption.
• Developing secure, cost-effective multimode PersL phosphors is crucial.

Purpose of the Study:

• To design and investigate a novel non-rare earth-doped multimode PersL phosphor.
• To explore its potential for advanced information storage and encryption applications.
• To address the limitations of existing PersL materials.

Main Methods:

• Synthesis and characterization of SrGa₂Ge₂O₈:Cu²⁺ (SGGO:Cu²⁺) phosphor.
• Analysis of its photoluminescence properties, including yellow-green PersL and near-infrared emission.
• Evaluation of thermal quenching, photochromism, and thermochromism.

Main Results:

• A novel SGGO:Cu²⁺ phosphor exhibiting yellow-green PersL (535 nm) and UV-excited near-infrared emission was successfully synthesized.
• The phosphor demonstrated distinct thermal quenching behaviors for its luminescence peaks.
• Remarkable reversible photochromism (white to gray under 254 nm UV light) and thermochromism were observed.

Conclusions:

• The developed SGGO:Cu²⁺ phosphor functions as a multimode luminescent material.
• Its combination of PersL, thermochromism, and photochromism offers significant potential for secure optical information storage and encryption.
• This work presents a promising alternative to expensive rare earth-doped materials.