Abstracts
Quantum dots, nanocrystals, and nano-structured luminescent materials
Thermal stability of [Eu(tta)3(H2O)2] complex incorporated in sustainable urethanesil film: Spectroscopic and theoretical studiesFábio J. C. L. F. S. B. D. de F. B. S. D. O. S. H. S. R. B. A. M. P. S. J. L. Ribeiro11
11. São Paulo State University, Institute of Chemistry, Brazil; 2. São Paulo State University, School of Technology and Sciences, Brazil; 3. São Paulo State University, Institute of Biosciences, Humanities and Exact Sciences, Brazil; 4. University of Ribeirão Preto, Brazil
E-mail: fjcaixeta@alumni.usp.br
Despite recent efforts to develop luminescent rare earth β‑diketonate complexes, the attainment of thermal stability continues to pose a formidable challenge. The present study addresses this issue by embedding a Eu3+-complex into a sustainable organic-inorganic hybrid to harness thermal stability. We report thermal-stabilized tris(thenoyltrifluoroacetonate) europium(III) complex, [Eu(tta)3(H2O)2], incorporated into a urethanesil castor oil‑based hybrid (SiCO) material. Spectroscopic analysis reveals that heating [Eu(tta)3(H2O)2] in powder form to 60 °C results in irreversible quenching of its photoluminescence (PL) emission. On the other hand, the PL emission of [Eu(tta)3(H2O)2] complex does not change after annealing the SiCO‑[Eu(tta)3(H2O)2] film up to 180 °C. Furthermore, [Eu(tta)3(H2O)2] coordination compound incorporated into the hybrid material proved to be thermally stable, maintaining its luminescent properties even after undergoing at least five successive heating‑cooling cycles ranging from 29 to 70 °C. By theoretical calculations on intramolecular energy transfer (IET), it was found that temperature changes in SiCO‑[Eu(tta)3(H2O)2] film dramatically affects IET dynamics. The increase in the temperature led to a reduction of tta→Eu3+ ET rates along the main pathway, T1:tta→5DJ/5L6:Eu3+, while an increase in S1+T1:tta←5DJ/5L6:Eu3+ backward IET was verified. This is a pioneering material, that represents a significant advance in the field of Materials Science. This innovative optical material not only shed light on the critical aspects of thermal stability in luminescent hybrid materials but also opens avenues for diverse applications in photonics, where such stability is of paramount importance.
Keywords: Europium (III), β-diketonate complex, castor oil, photoluminescence, intramolecular energy transfer, photonics.
Acknowledgments: The authors gratefully acknowledge the financial support provided by INCT-INFO, CAPES, CNPq (Grant No. 309448/2021-2), and FAPESP (Gant No. 2022/03652-8 and 2023/05718-9).