Glass crystallization making red phosphor for high-power warm white lighting

Area of Science:

• Materials Science
• Solid-State Lighting
• Luminescence

Background:

• Solid-state lighting (SSL) technology demands efficient and stable luminescent materials, particularly red phosphors for enhanced light quality.
• Blue light-pumped red phosphors are crucial for improving the color rendering and overall performance of SSL devices.

Purpose of the Study:

• To discover and characterize a novel red-emitting phosphor for high-performance solid-state lighting applications.
• To investigate the luminescence properties, quantum efficiency, and thermal stability of the newly developed phosphor.

Main Methods:

• Crystallization of MgO-Al₂O₃-SiO₂ aluminosilicate glass to form the Mg₂Al₄Si₅O₁₈:Eu²⁺ phosphor.
• Experimental measurements of photoluminescence, quantum efficiency, and thermal quenching.
• First-principles calculations to understand the mechanism of Eu²⁺ doping and emission.

Main Results:

• Discovery of an unprecedented red-emitting Mg₂Al₄Si₅O₁₈:Eu²⁺ phosphor with excitation at 450 nm and emission at 620 nm.
• High internal quantum efficiency (94.5%) and external quantum efficiency (70.6%) were achieved.
• The phosphor demonstrated excellent thermal stability, resisting quenching at high temperatures, and reached industrial production standards.
• A laser-driven red-emitting device using this phosphor achieved a maximum luminous flux of 274 lm and luminous efficiency of 54 lm W^-1.

Conclusions:

• The Mg₂Al₄Si₅O₁₈:Eu²⁺ phosphor exhibits extraordinary optical properties, including high efficiency and stability.
• The preparation method is economically favorable and innovative, suitable for industrial production.
• This phosphor represents a significant advancement for the development of high-power solid-state lighting solutions.