MULTIFUNCTIONAL NANOSTRUCTURED MATERIALS FOR OPTICAL NANOTHERMOMETRY

Nanothermometry is a discipline of science that studies temperature sensing at the micro and nanoscale levels. Temperature measurement is now used in a wide variety of scientific, industrial, and technical applications, ranging from basic research to nanotechnology and medical diagnostics. At the nanoscale, where materials and systems exhibit unique features and behaviours, traditional temperature monitoring methods have limited spatial resolution and sensitivity. The purpose of nanothermometry is to overcome such limitations by developing novel approaches to sensing temperature at the nanoscale. This implies using temperature-dependent features of nanothermometer materials such as electrical, mechanical, or optical properties. The fundamental goal of my research was the investigation of new materials for optical nanothermometry, with particular interest on its application in biomedicine. Three main projects will be explained: (i) Raman nanothermometry using Titanium Dioxide Anatase, both in commercial powder and nanoparticle form, for visible and near-infrared temperature sensing; (ii) dual-mode nanothermometry, of a nanocomposite combining a Raman-active material, TiO2, with a luminescent material, up-converting CaF2 doped with Yb and Er; (iii) Temperature monitoring, using Nd-based nanothermometers, during photothermal therapies, resulting from the irradiation of gold nanorods coated in dense or mesoporous silica shells, with near-infrared light. A brief introduction will outline a base for understanding the main results of my research, providing an insight into the potential applications of nanothermometry, in particular in biomedicine, the nanothermometric techniques, and an overview of the nanomaterials used for nanothermometry and photothermal treatments. The outcomes of the three projects are then described and discussed, and then finally, conclusions are presented in view of these findings, and the future perspectives of the projects are provided.