Multifunctional applications based on the anomalous ⁵D₀ → ⁷F₄ transition in SrGa₄O₇: Eu³

Area of Science:

• Materials Science
• Solid-State Chemistry
• Luminescence

Background:

• Europium (Eu³⁺)-doped phosphors are crucial for lighting and displays, emitting orange/red light via ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂ transitions.
• Existing phosphors have limitations including low efficiency and weak ⁵D₀ → ⁷F₄ transitions, restricting far-red emission.
• There is a need for efficient deep-red emitting phosphors for specialized applications like plant cultivation.

Purpose of the Study:

• To develop and characterize novel deep-red emitting phosphors based on SrGa₄O₇ doped with Eu³⁺.
• To investigate the utilization of the ⁵D₀ → ⁷F₄ transition for efficient far-red emission.
• To evaluate the potential of these phosphors in white light-emitting diodes (WLEDs) for plant lighting and other applications.

Main Methods:

• Synthesis and characterization of SrGa₄O₇: 0.3Eu³⁺ (SGO: 0.3Eu³⁺) phosphors.
• Photoluminescence spectroscopy under near-UV excitation to analyze emission transitions.
• Thermal stability measurements and quantum yield determination.
• Fabrication and testing of WLEDs incorporating the developed phosphors for plant growth applications.

Main Results:

• SGO: 0.3Eu³⁺ phosphors predominantly utilize the ⁵D₀ → ⁷F₄ transition (701 nm) for efficient deep-red emission.
• The optimized phosphor exhibits excellent thermal stability, retaining significant emission intensity at elevated temperatures (425 K).
• A high quantum yield of 31.95% was achieved when excited at 393 nm.
• WLEDs incorporating SGO: 0.3Eu³⁺ demonstrated suitable spectral properties for plant cultivation, with excellent color rendering (CRI 91.9) and color purity (96.4%).

Conclusions:

• SGO: 0.3Eu³⁺ is a promising deep-red emitting phosphor overcoming limitations of conventional Eu³⁺-doped materials.
• Its superior thermal stability, high quantum yield, and efficient far-red emission make it ideal for plant lighting.
• Potential applications extend to fingerprint detection, anti-counterfeiting inks, and other fields requiring high-quality red emission.