Luminescent Platform for Thermal Sensing and Imaging Based on Structural Phase-Transition.

Area of Science:

• Materials Science
• Luminescence
• Solid-State Chemistry

Background:

• Europium (Eu3+) ion luminescence is sensitive to its crystal environment.
• Luminescent thermometers based on phase transitions offer contactless sensing but often have limited operating ranges.
• New host materials are needed to overcome limitations in luminescent thermometry.

Purpose of the Study:

• Investigate Na3Sc2(PO4)3:Eu3+ as a host material for luminescent thermometry.
• Explore the material's phase transition and its effect on Eu3+ luminescence.
• Develop and demonstrate novel temperature sensing and imaging capabilities.

Main Methods:

• Synthesized Na3Sc2(PO4)3 doped with varying concentrations of Eu3+.
• Characterized luminescence properties (emission spectra, decay times) as a function of temperature.
• Investigated the structural phase transition from monoclinic to trigonal.
• Demonstrated temperature imaging using a digital camera without optical filters.

Main Results:

• Na3Sc2(PO4)3:Eu3+ exhibits a reversible monoclinic-trigonal phase transition.
• Phase transition significantly alters Eu3+ emission spectra and luminescence decay.
• Achieved maximum relative sensitivities of 3.4% K-1 (ratiometric) and 1.0% K-1 (lifetime-based).
• Tuned thermal operating range by adjusting Eu3+ concentration.
• Successfully demonstrated filter-free temperature imaging using Eu3+ luminescence.

Conclusions:

• Na3Sc2(PO4)3:Eu3+ is a promising multifunctional material for luminescent thermometry.
• The material's tunable properties and imaging capability are advantageous for contactless temperature sensing.
• This work pioneers filter-free thermal imaging with a single Eu3+-doped phosphor.