N‐Rich Porous Polymer with Isolated Tb3+‐Ions Displays Unique Temperature Dependent Behavior through the Absence of Thermal Quenching

• Published in: Chemistry : a European journal 2020-12, Vol.26 (67), p.15596-15604
• Main Authors: Vanden Bussche, Flore, Kaczmarek, Anna M., Veerapandian, Savita K. P., Everaert, Jonas, Debruyne, Maarten, Abednatanzi, Sara, Morent, Rino, De Geyter, Nathalie, Van Speybroeck, Veronique, Van Der Voort, Pascal, Stevens, Christian V.
• Format: Article
• Language: English
• Subjects: Chemistry; Conjugation; Emission; Emission standards; Energy transfer; Europium; Grafting; Lanthanides; Polymers; porous organic polymer; Quenching; ratiometric thermometer; sensors; Temperature dependence; Temperature sensors; thermal quenching; Thermometers
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202002009

The challenge of measuring fast moving or small scale samples is based on the absence of contact between sample and sensor. Grafting lanthanides onto hybrid materials arises as one of the most promising accurate techniques to obtain noninvasive thermometers. In this work, a novel bipyridine based porous organic polymer (bpyDAT POP) was investigated as temperature sensor after grafting with Eu(acac)3 and Tb(acac)3 complexes. The bpyDAT POP successfully showed temperature‐dependent behavior in the 10–310 K range, proving the potential of amorphous, porous organic frameworks. We observed unique temperature dependent behavior. More intriguingly, instead of the standard observed change in emission as a result of a change in temperature for both Eu3+ and Tb3+, the emission spectrum of Tb3+ remained constant. This work provides framework‐ and energy‐based explanations for the observed phenomenon. The conjugation in the bpyDAT POP framework is interrupted, creating energetically isolated Tb3+ environments. Energy transfer from Tb3+ to Eu3+ is therefore absent, nor energy back transfer from Tb3+ to bpyDAT POP ligand (i.e. no thermal quenching) is detected. A novel bipyridine‐based porous organic polymer (bpyDAT POP) is investigated as temperature sensor after grafting with Eu(acac)3 and Tb(acac)3 complexes. The material successfully demonstrates the potential of amorphous, porous polymers in temperature sensing. Furthermore, peculiar temperature dependent behavior is observed through the interruption of conjugation in the framework and the absence of thermal quenching.