N ‐ Rich Porous Polymer with Isolated Tb 3+ ‐Ions Displays Unique Temperature Dependent Behavior through the Absence of Thermal Quenching

• Published in: Chemistry : a European journal Vol. 26; no. 67; pp. 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: Journal Article
• Language: English
• Published: 01.12.2020
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202002009

Abstract 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 Eu 3+ and Tb 3+ , the emission spectrum of Tb 3+ 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 Tb 3+ environments. Energy transfer from Tb 3+ to Eu 3+ is therefore absent, nor energy back transfer from Tb 3+ to bpyDAT POP ligand (i.e. no thermal quenching) is detected.