Estudo das propriedades ópticas e térmicas de nanopartículas luminescentes do tipo núcleo@casca dopadas com íons terra-raras

Abstract

One of the great hallmarks of our century is the search for interdisciplinarity, which has increasingly helped to combine technologies produced by different fields. A good example of this is nanobiophotonics, which integrates advances in photonics, nanotechnology and biotechnology. This junction has boosted the synthesis of luminescent nanoparticles (materials that emit light at a certain wavelength when optically excited) with sizes of only a few nanometers and with different physical, chemical and biological functionalities for different applications in the field of industry and biomedicine. With respect to biomedical applications, luminescent nanoparticles (NPsL) have emerged as powerful tools providing new perspectives on imaging, diagnosis and therapy, both in in vitro experiments (cells, for example) and in vivo (small animals). Among the various types of nanoparticles luminescents doped and co-doped with Ln3+ ions such as, for example, Yb3+, Er3+, Tm3+, Ho3+ and Nd3+ stand out from those with a core@shell and/or core@multishell structure, which thanks to nano-engineering have managed to improve/control the transfer of energy between sensitizer and activator, avoiding the unwanted effect of “reverse transfer” and, therefore, optimizing the efficiency of light emission from the ultraviolet to the near infrared, when compared to their single core analogues. this work aims to study the optical properties of colloidal systems formed by core@shell nanoparticles through the evaluation of their properties. optics of emission as a function of temperature, to act as multifunctional nanoparticles, that is, nanoparticles capable of acting as thermal sensors and nanoheaters simultaneously. For this purpose, CaF2 nanoparticles of different structures were developed, including single core and core@shell co-doped with Yb3+, Er3+ and Tm3+ .