Lanthanide-based Metal-Organic frameworks as luminescent nanothermometers – THERMOF

Precise temperature measurement at the submicrometer scale is an important challenge encountered, namely, in the fields of nanotechnology and nanomedicine. Thermometers working in an accurate, non-invasive way and with a high spatial resolution are critical to monitoring numerous processes at the microscale and nanoscale within electronic and photonic devices, such as thermal transport, thermal reactions... The first approaches to nano-thermometry tried to miniaturize the geometrical size of the conventional thermometers (or contact thermometers), in which the measurement of temperature is achieved by heat flow to an invasive probe. However this miniaturization is not sufficient and the contact nature of such measurements makes the conventional thermometers not suitable to measure the temperature of fast-moving objects or in scales below 10 micrometers (e.g. intracellular temperature fluctuations, temperature at molecular scale, or in microcircuits and microfluids). Therefore a new generation of non-contact thermometers is currently demanded to accurately measure temperature distributions down to the nanoscale regime. Eu-Tb mixed-metal-organic framework thermometers have very recently appeared as a new promising generation of self-calibrated luminescent thermometers for the accurate measurement of temperature distributions down to the nanoscale regime. The temperature measure is based on the temperature-dependence of the intensity ratio of two separate electronic transitions (the transitions 5D4?7F5 and 5D0? 7F2 of the Tb3+ and Eu3+ ions, respectively). In this new hot topic, efforts must be done to develop highly performant materials but also to rationalize the different occurring phenomena. In that context, the THERMOF project deals with the highlighting, through pertinent composition- and structure-property relationships, of the key parameters governing the main optical characteristics of the Eu-Tb mixed-MOF thermometers. The project will also be dedicated to the synthesis of nanoparticles of these MOFs and to the study of the nanostructuration impact on materials performances to envision a long-term practical use.