Development of devices based on persistent luminescence thin films

Abstract

Luminescent materials are widely used in various applications, e.g.: emergency signaling, luminescent paints, temperature and pressure sensors, biomarkers, creation of thin films, etc. A luminescent material is a compound that generally converts the energy absorbed into electromagnetic radiation to one of lower energy, except in the case of absorption of two or more photons (upconversion) that generates higher energy radiation. These compounds, for the most part, are found as solids of an inorganic host doped with an activator ion such as lanthanides (ions 4fn, Ln: Ce-Lu). Generally, those activators are responsible for the phenomenon of photoluminescence in crystals, since they can attribute a very well defined excitation and emission spectra to the material.For new applications, it is desired to obtain glasses or translucent devices which exhibit persistent luminescence optical properties. This project has the focus of studying the development, application and properties of persistent thin films (FFP). A thin film is a layer of material that can vary between nanometers and micrometers of thickness. Thin films of metals (e.g., Al, Au, Ag, Cu, etc.), oxides (ZnO, SnZnO, Al2O3, TiO2 etc.) and nitrides (Si3N4, etc.) are well known and have very well-defined applications, e.g., solar cells, detectors, LEDs, ornaments, electronic devices, electrical circuits, among other applications studied through the properties of each material. The development of persistent thin films is not yet established in the literature. Despite the great demand of these films for new applications (eg lighting, converters and light storage for bioreactors etc.), there is a great difficulty in obtaining these films. This difficulty lies not only in finding adequate deposition parameters, but also in the entire development of the solution to be deposited from synthesized particles and nanoparticles. According to this, the development of a device created from FFP deposited under vitreous surfaces will shed light upon futures works on its applications, opening a pathway to new researches.we will initially study the nanoparticle synthesis of inorganic crystals (Sr2MgSi2O7: Eu2 +, Dy3 +, Ba2MgSi2O7: Eu2 +, Tm3 +, Sr2Al2SiO7: Eu2 +, Dy3 + and SrS: Eu2 +, Sm3 +), organic and aqueous suspension of those nanoparticles and the deposition of luminescent thin films on vitreous surfaces by spin coating and by wet powder spray techniques, also others deposition techniques will be studied, such as chemical vapor deposition. (AU)