Highly-sensitive Eu(3+) ratiometric thermometers based on excited state absorption with predictable calibration

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Accurate temperature measurements are crucial for nanomedicine and nanotechnology.
• Existing thermometers may have limitations in specific temperature ranges or media.

Purpose of the Study:

• To develop a novel ratiometric luminescent thermometer for precise temperature measurements.
• To demonstrate its utility in the nanomedicine and nanotechnology fields.

Main Methods:

• Utilized thermally excited state absorption of the europium (Eu3+) ion.
• Employed Y2O3:Eu3+ nano and microcrystals as the thermometric material.
• Defined the thermometric parameter as a ratio of emission intensities from different Eu3+ transitions.

Main Results:

• The thermometer operates effectively between 180 K and 323 K.
• Achieved a relative sensitivity between 0.7% K(-1) and 1.7% K(-1).
• Demonstrated that calibration factors can be derived directly from the Eu3+ emission spectrum, eliminating the need for recalibration in different media.

Conclusions:

• The developed Eu3+-based luminescent thermometer offers a robust and versatile solution for temperature sensing.
• Its ability to self-calibrate simplifies application across various media, a significant advancement for nanomedicine and nanotechnology.
• The thermometer operates within the first biological transparent window, enabling in-situ biological applications.