Stable Long-Persistent Luminescence from Self-Activated CaSb₂O₆ Induced by Intrinsic Defects

Area of Science:

• Materials Science
• Solid State Chemistry
• Luminescence

Background:

• Long-persistent luminescence (LPL) materials are crucial for various applications but often require complex doping for trap/emitting centers.
• Current LPL materials face challenges in synthesis complexity and controllability due to external doping requirements.

Purpose of the Study:

• To introduce a novel category of undoped long-persistent luminescence (LPL) materials.
• To investigate the potential of antimonate CaSb2O6 as an intrinsic LPL material.
• To elucidate the mechanism behind the LPL in undoped CaSb2O6.

Main Methods:

• Synthesis of undoped antimonate CaSb2O6.
• Experimental characterization of luminescence properties.
• Theoretical calculations to understand trapping and emission mechanisms.
• Stability tests under high temperature, UV irradiation, and extreme pH conditions.

Main Results:

• Discovery of blue LPL in undoped CaSb2O6, persisting over 8000 seconds.
• Identification of intrinsic oxygen vacancies as exciton traps.
• Confirmation of exciton detrapping and recombination via Sb3+ singlet/triplet emission.
• Demonstration of exceptional stability: ~100% LPL performance retention after 1000 °C, UV, and extreme pH (1 or 13) treatments.

Conclusions:

• Undoped antimonate CaSb2O6 represents a new class of robust LPL materials.
• Intrinsic defects, specifically oxygen vacancies, can effectively facilitate LPL without external doping.
• Antimonates show significant promise as stable and versatile materials for advanced luminescent applications.