UChicago PME Quantum Science and Engineering Seminar - Gautier FELIX

Measuring Nanoscale Thermal Responses to External Stimuli in Nanoparticle Ensembles

Precise control of nanoscale heat generation and temperature monitoring is essential for advancing applications in catalysis, materials science, nanomedicine, etc. Inorganic nanoparticles, such as iron oxide or Prussian blue, can operate in liquid environments or when immobilized on surfaces, offering versatile platforms for localized thermal manipulation when subjected to external stimuli such as light irradiation. However, experimental access to temperature at the nanoscale remains limited, making the development of reliable thermometric tools a key challenge. In this presentation, two complementary strategies addressing this challenge will be discussed. The first focuses on luminescent nanothermometers based on molecular complexes of lanthanide ions, notably Tb3+ and Eu3+, embedded in silica shells surrounding photothermal cores. These hybrid systems enable ratiometric temperature readout with high sensitivity and reproducibility, allowing accurate thermal mapping in aqueous media or on surfaces. The second strategy explores the use of nanoparticle-mediated heating to induce the homolysis of thermosensitive alkoxylamine derivatives. This reaction releases radicals through bond cleavage, with nanoscale heat acting as the trigger. By analyzing the kinetics of radical formation, the local temperature experienced by the molecule during homolysis can be inferred, offering an alternative method for nanoscale thermometry based on reaction dynamics. These approaches contribute to a deeper understanding of heat propagation at the nanoscale, particularly in systems involving confined heating from nanoparticle cores. Beyond chemical reactivity, they also provide insights into thermal exchange between nanomaterials and their surrounding environment, with potential applications such as heat-triggered drug release.