Deep red fluoride dots-in-nanoparticles for high color quality micro white light-emitting diodes

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nanotechnology

Background:

• Development of efficient red-emitting phosphors is crucial for high-quality white light-emitting diodes (WLEDs).
• Existing red phosphors often face challenges with color purity, quantum efficiency, and thermal stability.
• Novel nanostructures offer opportunities to overcome these limitations.

Purpose of the Study:

• To synthesize and characterize a novel nanostructure of fluoride red-emitting phosphor.
• To investigate the optical and thermal properties of the synthesized material.
• To evaluate its application as a red component in warm white LEDs.

Main Methods:

• Synthesis of porous K₂SiF₆:Mn⁴⁺ nanoparticles with embedded K₂SiF₆:Mn⁴⁺ nanocrystals using soft templates.
• Formation of dots-in-nanoparticles (d-NPs) structures.
• Characterization of optical properties (emission, quantum yield, CIE coordinates) and thermal stability.
• Integration of the nanophosphor onto InₓGa₁₋ₓN nanowire LEDs to fabricate WLEDs.

Main Results:

• Successfully synthesized porous K₂SiF₆:Mn⁴⁺ d-NPs with controlled optical properties.
• Achieved sharp, deep red emission with a quantum yield of ~95.9% and ultra-high color purity (CIE: x=0.7102, y=0.2870).
• Demonstrated good thermal stability between 300 K and 500 K.
• Fabricated WLEDs exhibited an excellent color rendering index (~95.4) and low correlated color temperature (~3649 K).

Conclusions:

• Porous K₂SiF₆:Mn⁴⁺ d-NPs represent a promising red-emitting material.
• The unique d-NPs structure enables controlled optical properties and high performance.
• These nanophosphors are suitable for high color quality micro WLED applications.