Europium Complex for High-Sensitivity Temperature Sensing in the Physiological Range

• Published in: Materials 2022-10, Vol.15 (21)
• Main Authors: Soler-Carracedo, Kevin, Díaz-González, María, Ma, Rios, Susana, Gil-Hernández, Beatriz, Brito-Santos, Gabriela, Sanchiz, Joaquín
• Format: Article
• Language: English
• Subjects: Measuring instruments; Optical properties; Rare earth metals; Sensors
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15217501

A new Eu[sup.3+]-doped Gd[sup.3+] complex of formula [Eu[sub.0.0135]Gd[sub.0.9865](pta)[sub.3]me-phen] was synthesized and structurally characterized (Hpta = benzoyltrifluoroacetone, me-phen = 5-methyl-1,10-phenanthroline). The photoluminescence study revealed that when the compound was excited at RT, under a 457 nm continuous laser, the material exhibited high luminescence due to the antenna effect of the ligands, as well as a good balance between the phosphorescence from the spin-forbidden triplet (from the organic ligands), and the characteristic lanthanide f-f transitions. The ratio between the previous emissions drastically changed when the sample was heated up to 62 °C inside a tubular furnace. This ratio was investigated using the luminescence intensity ratio method, to analyze the capabilities of the sample as a temperature sensor. The relative sensitivity reached a maximum of 11.4 °C[sup.−1] %, maintaining a detection limit below 0.15 °C for the whole temperature range.