Developing Luminescent Ratiometric Thermometers Based on a Covalent Organic Framework (COF)

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Covalent Organic Frameworks (COFs) are emerging crystalline porous materials.
• Lanthanide ions (Ln3+) exhibit luminescence properties suitable for sensing applications.

Purpose of the Study:

• To develop novel hybrid materials for ratiometric luminescent thermometry.
• To investigate the use of COFs as supports for lanthanide ions in temperature sensing.

Main Methods:

• Synthesis of a TpBpy-COF using 1,3,5-triformylphloroglucinol (Tp) and 2,2'-bipyridine-5,5'-diamine (Bpy).
• Grafting of Europium (Eu), Terbium (Tb), and Dysprosium (Dy) acetylacetone (acac) complexes onto the COF.
• Evaluation of the luminescent properties for temperature sensing in different ranges.

Main Results:

• The synthesized LnCOF materials successfully functioned as ratiometric luminescent thermometers.
• Eu-based thermometers operated in the 10-360 K range, and Tb-based thermometers operated in the 280-440 K range.
• High thermal sensitivity (up to 1.403 % K-1) and low temperature uncertainty (δT < 1 K above 110 K) were achieved.
• Absence of thermal quenching for Tb3+ emission was observed due to suppressed energy back-transfer.

Conclusions:

• LnCOF materials represent a new class of materials for advanced temperature-sensing applications.
• The unique properties of these hybrid materials offer advantages over traditional luminescent thermometers.
• Further research into COF-based luminescent materials is warranted for thermometry and other sensing applications.