High-Purity Narrow-Band Green Light KAl₁₁O₁₇: Eu²⁺, Mn²⁺ Phosphor Prepared Based on Energy Transfer Effect

Area of Science:

• Materials Science
• Solid-State Chemistry
• Luminescence

Background:

• High-quality backlight displays require phosphors with specific optical and thermal properties.
• Developing narrow-band green emitters with high color purity and stability is crucial for wide color-gamut applications.

Purpose of the Study:

• Synthesize and characterize a novel narrow-band green-emitting phosphor, KAl11O17 (KAO):Eu2+, Mn2+.
• Investigate the structure-property relationships, focusing on ion occupancy and energy transfer mechanisms.
• Evaluate the phosphor's performance for potential use in wide color-gamut WLED backlight displays.

Main Methods:

• High-temperature solid-state reaction for phosphor synthesis.
• X-ray diffraction (XRD) for structural refinement and site occupancy determination.
• Photoluminescence spectroscopy for emission properties, quantum efficiency, and energy transfer analysis.
• Thermal analysis to assess luminescence stability at elevated temperatures.
• Fabrication of a white LED device incorporating the optimized phosphor.

Main Results:

• KAl11O17 (KAO):Eu2+, Mn2+ synthesized with Eu2+ at K+ sites and Mn2+ at Al3+ sites.
• Efficient energy transfer from Eu2+ to Mn2+ via a dipole-quadrupole mechanism observed.
• Optimized phosphor (KAO: 0.07Eu2+, 0.04Mn2+) shows narrow-band green emission (510 nm, FWHM 8.13 nm), high color purity (98%), and internal quantum efficiency (65.41%).
• Excellent thermal stability demonstrated, retaining 93.11% luminescence at 423 K.
• Fabricated WLED device achieved 107.8% NTSC color-gamut coverage.

Conclusions:

• Precise control over site occupancy and energy transfer in KAO:Eu2+, Mn2+ leads to superior narrow-band green emission.
• The developed phosphor exhibits key properties (narrow emission, high purity, thermal stability) essential for advanced WLED displays.
• This work highlights a viable strategy for designing high-performance phosphors for wide color-gamut applications.