Abstracts

Luminescent thermometry is not only one of the most accurate methods of temperature measurement, but is also indispensable for non-contact temperature measurement. One of the most important applications of luminescent thermometry is the measurement of high temperatures, for example, engine parts and gas pipeline walls, where almost the only measurement method is non-contact luminescent thermometry. In addition, it allows for continuous real-time measurements and even mapping. Inorganic materials are usually used as luminescent thermometers at high temperatures. Despite the low intensity of their luminescence, they are stable up to very high temperatures, while the thermal stability of brightly luminescent coordination compounds (CCs) is insufficient. However, metal-organic frameworks (MOFs) based on lanthanide aromatic carboxylates are often stable to temperatures of 400-600 °C, sufficient for a number of thermometric applications, and exhibit very intense luminescence.We proposed using heterometallic aromatic lanthanide carboxylates as high-temperature fluorescent thermometers in composite films based on transparent heat-resistant polymer materials. We proposed an analytical description of a four-level system for luminescent thermometry, including one main and three excited states, which include Tb-Eu complexes with an organic ligand, and demonstrated a strategy for creating such systems to increase temperature sensitivity. Based on this study, new approaches to increasing sensitivity due to a complex design have been proposed.We have conducted a number of studies of highly stable complexes as emitters for high-temperature luminescent thermometry, studied the stability of complexes under simultaneous exposure to UV excitation and heating, as well as the features of the formation of composite films with polymers of different classes. As a result, materials capable of operating up to 400 °C in both the visible and NIR ranges were obtained. We have also demonstrated, both mathematically and experimentally, that mixtures of monometallic complexes are more sensitive than the corresponding bimetallic compounds.