Ratiometric thermometry using single Er³⁺-doped CaWO₄phosphors

Area of Science:

• Materials Science
• Solid State Physics
• Spectroscopy

Background:

• Optical thermometry offers non-contact temperature measurement capabilities.
• Ratiometric methods enhance accuracy and self-referencing in luminescent thermometers.
• Erbium-doped calcium tungstate (CaWO₄:Er³⁺) phosphors are explored for thermometric applications.

Purpose of the Study:

• To synthesize and investigate single-doped CaWO₄:Er³⁺ phosphors for optical thermal sensing.
• To evaluate the performance of a dual-mode ratiometric strategy for temperature readout.
• To analyze the effect of Er³⁺ doping concentration on sensing properties.

Main Methods:

• Synthesis of single doped CaWO₄:Er³⁺ phosphors.
• Optical characterization including luminescence spectroscopy.
• Application of a ratiometric strategy using two luminescence intensity ratios (LIR₁ and LIR₂).
• Evaluation of thermometric parameters: sensitivity, temperature resolution, and repeatability.

Main Results:

• CaWO₄:Er³⁺ phosphors demonstrated effective optical thermal sensing from 98 K to 773 K.
• The dual-mode ratiometric strategy provided self-referencing temperature readouts.
• LIR₁ achieved a maximum sensitivity of 2.09% K^-1 at 300 K.
• LIR₂ offered high accuracy with a temperature resolution of 0.06–0.1 K.
• Er³⁺ doping concentration influenced the sensing properties.

Conclusions:

• CaWO₄:Er³⁺ phosphors are promising materials for dual-mode optical thermal sensing.
• The dual-parameter ratiometric approach enhances thermometric performance and broadens the working temperature range.
• The developed phosphors exhibit high sensitivity and sub-degree temperature resolution, suitable for advanced thermal sensing applications.