High-Quantum-Efficiency Pr³⁺-Doped Li₇La₃Zr₂O₁₂ Garnet and Associated Temperature-Sensing Performance

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photonics

Background:

• Understanding energy transfer in Pr³⁺ is crucial for developing efficient luminescent thermometers.
• Optimizing temperature-sensing performance relies on high quantum efficiency and distinct excitation/emission mechanisms.

Purpose of the Study:

• To introduce a novel Pr³⁺-doped tetragonal-phase Li₇La₃Zr₂O₁₂ (Pr³⁺:LLZO) garnet as a luminescent thermometer.
• To investigate the photoluminescence (PL) properties and energy transfer mechanisms within Pr³⁺:LLZO.
• To develop a luminescence thermometry strategy based on differential quenching behaviors of Pr³⁺ excited states.

Main Methods:

• Composition optimization of Pr³⁺:LLZO phosphors.
• Photoluminescence (PL) spectroscopy to analyze emission properties.
• Investigation of thermally induced fluorescence quenching mechanisms (phonon-assisted thermal ionization and cross-relaxation).

Main Results:

• Achieved a high room-temperature PL quantum efficiency of 77.48% in Pr³⁺:LLZO, surpassing traditional garnet phosphors.
• Identified distinct thermal quenching mechanisms: phonon-assisted thermal ionization for ³P₀ and cross-relaxation for ¹D₂ emissions.
• Demonstrated a comparable temperature-sensing capability using a thermometry strategy based on these different quenching behaviors.

Conclusions:

• The study highlights the importance of understanding Pr³⁺ emission quenching mechanisms for material design.
• Pr³⁺:LLZO presents a promising new material for high-performance luminescent thermometry.
• The findings offer valuable insights for developing advanced Pr³⁺-doped garnet-type luminescent materials.