A Dual-Mode Optical Thermometer with High Sensitivity Based on BaAl₁₂O₁₉:Sm²⁺/SrAl₁₂O₁₉:Sm³⁺ Solid Solution Phosphors

Area of Science:

• Materials Science
• Solid-state Chemistry
• Luminescence

Background:

• Developing advanced phosphors for noncontact thermometry is crucial for various industrial and scientific applications.
• Samarium (Sm)-doped aluminates offer tunable optical properties, but achieving dual-valence states for enhanced thermometry requires specific host engineering.

Purpose of the Study:

• To synthesize and characterize novel mixed-phase BaAl12O19:Sm2+/SrAl12O19:Sm3+ phosphors.
• To investigate the temperature-dependent luminescence properties of these phosphors for thermometry applications.
• To evaluate the potential of these materials as noncontact optical thermometers.

Main Methods:

• High-temperature solid-phase synthesis of mixed-phase BaAl12O19:Sm2+/SrAl12O19:Sm3+ phosphors.
• Analysis of crystal structure, ion emission spectra, and photoluminescence properties.
• Measurement of temperature sensitivity using fluorescence intensity ratio (FIR) and photoluminescence lifetime methods.

Main Results:

• Successfully synthesized mixed-phase phosphors with coexisting Sm2+ and Sm3+ ions in BaAl12O19 and SrAl12O19 hosts, respectively.
• Demonstrated excellent temperature measurement performance in the 313–513 K range using the FIR method, with a maximum absolute sensitivity (Sa) of 0.55 K-1.
• Achieved high relative temperature sensitivity (Sr) of 3.10%K-1 at 473 K using the photoluminescence lifetime method.

Conclusions:

• The BaAl12O19:Sm2+/SrAl12O19:Sm3+ solid solution phosphors exhibit significant potential for noncontact optical thermometry.
• The distinct temperature sensitivities of Sm2+ and Sm3+ ions in the mixed-phase host enable accurate temperature sensing.
• These phosphors offer a promising platform for developing next-generation temperature measurement devices.