Broadband Shortwave Infrared-Emitting Cr³⁺- and Ni²⁺-Codoped Y₃Al₂Ga₃O₁₂ Phosphor with Excellent Thermal Stability...

Area of Science:

• Materials Science
• Solid-State Lighting
• Luminescence

Background:

• Shortwave infrared (SWIR) materials are crucial for applications like noninvasive analysis and night vision.
• Current challenges include a lack of intense blue-light-pumped SWIR phosphors and poor thermal stability in existing Ni²⁺-activated phosphors.

Purpose of the Study:

• To develop a next-generation SWIR phosphor-converted light-emitting diode (pc-LED) material with improved performance.
• To address the limitations of current SWIR luminescent materials for advanced applications.

Main Methods:

• Synthesized and characterized a Y₃Al₂Ga₃O₁₂:Cr³⁺,Ni²⁺ phosphor for blue-light excitation.
• Investigated Cr³⁺ → Ni²⁺ energy transfer for SWIR emission enhancement.
• Employed X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and density functional theory (DFT) for structural analysis.

Main Results:

• Achieved ultrawide SWIR emission centered at ~1430 nm with a 440 nm blue-light excitation.
• Observed an 18-fold enhancement in SWIR emission due to efficient Cr³⁺ → Ni²⁺ energy transfer.
• Demonstrated excellent thermal stability with 90% emission remaining at 440 K, outperforming existing SWIR phosphors.

Conclusions:

• The Cr³⁺-Ni²⁺ codoped phosphor exhibits superior thermal stability and enhanced SWIR emission, overcoming current limitations.
• DFT calculations suggest [GaO₆] octahedrons as favorable sites for Ni²⁺/Cr³⁺ ions.
• A proof-of-concept SWIR pc-LED was fabricated, highlighting potential for invisible illumination, spectroscopy, and anticounterfeiting.