Novel high-efficiency and superior thermal stability red-emitting phosphors for WLEDs

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photonics

Background:

• Development of efficient phosphors is critical for near-ultraviolet (n-UV) light-emitting diode (LED) lighting.
• Broadband red phosphors are essential for achieving high-quality white light emission in LEDs.

Purpose of the Study:

• To design and synthesize a novel broadband red phosphor for n-UV LED applications.
• To investigate the luminescent properties and thermal stability of the synthesized phosphor.
• To evaluate the performance of the phosphor in white light-emitting diodes (WLEDs).

Main Methods:

• Utilized energy transfer between Eu²⁺ and Mn²⁺ in a Li₅MgSrAlB₁₂O₂₄ (LMSA) matrix.
• Synthesized Li₅MgSrAlB₁₂O₂₄:Eu²⁺,Mn²⁺ (LMSAB:Eu²⁺,Mn²⁺) phosphor.
• Characterized luminescent properties, quantum efficiency, and thermal stability.
• Fabricated WLEDs incorporating the developed phosphor.

Main Results:

• Successfully synthesized LMSAB:Eu²⁺,Mn²⁺, exhibiting broadband red emission (peak at 664 nm) and blue-violet emission (peak at 395 nm) upon n-UV excitation.
• Achieved high internal quantum efficiency (IQE = 91%) and external quantum efficiency (EQE = 71.4%).
• Demonstrated excellent thermal stability with 86.7% emission intensity retained at 423 K.
• WLEDs produced warm white light with a high color rendering index (R_a = 92.7) and luminous efficiency (57.59 lm W^-1).

Conclusions:

• LMSAB:Eu²⁺,Mn²⁺ is a promising broadband red phosphor for n-UV LED applications.
• The phosphor's high efficiency and thermal stability make it suitable for WLEDs.
• The developed material contributes to advancements in solid-state lighting technology.