Tb³⁺-based multi-mode optical ratiometric thermometry.

Area of Science:

• Materials Science
• Optical Thermometry
• Luminescence Spectroscopy

Background:

• Luminescence ratiometric thermometry, utilizing dual excitations or single excitation with dual emissions, is increasingly popular for temperature sensing.
• Developing multi-mode ratiometric thermometry remains a significant challenge in the field.

Purpose of the Study:

• To report a novel multi-mode temperature measurement method based on photoinduced luminescence.
• To demonstrate the feasibility of both luminescence intensity ratio (LIR) and single-band ratiometric (SBR) strategies in a single material.

Main Methods:

• Utilized low-cost and easily prepared terbium-doped calcium tungstate (Tb³⁺ in CaWO₄).
• Investigated temperature-dependent luminescence emissions from Tb^{3+ 5}D₄ and ⁵D₃ energy levels.
• Employed both conventional LIR and single-band ratiometric (SBR) approaches for thermometry.

Main Results:

• Achieved multi-mode ratiometric thermometry, demonstrating both LIR and SBR strategies.
• Developed an LIR thermometer with excitation-wavelength-dependent sensitivity.
• Constructed an SBR thermometer with a maximum relative sensitivity of 1.83% K^-1 at 573 K.

Conclusions:

• Successfully developed a versatile multi-mode optical ratiometric thermometer using Tb³⁺-doped calcium tungstate.
• The findings pave the way for designing advanced optical thermometers with tunable sensing capabilities.
• This work is expected to inspire further research into multi-mode ratiometric thermometry.