Sustainable Development of New Phosphors for Photonics Applications

Phosphors with high efficiency, long afterglow (long persistent luminescent phosphor (LPLP)), crystalline and reproducible property for use in diverse application such as in sensor, storage, and lighting devices has become the central attraction of research in recent years. Different materials have characteristics that enable the achievement of this. As already established by previous studies, the method of synthesis affects the crystalline properties of a phosphor material. Therefore, very important to use a technique that will not require post-synthesis annealing for high yield. Mechano-luminescence (ML) is the emission of light by a phosphor through a mechanical activity that was carefully studied using the single impact method with different energy. In this research, various materials of plain calcium zinc oxysulfide (CaZnOS) and calcium gallium oxide (Ca3Ga4O9 (CGO)) and their composites with Eu3+, Tb3+, Bi3+ Zn2+ were studied utilizing different synthesis routes. CaZnOS was carried-out for its high performance as a mechano-luminescent material, Ca3Ga4O9 was for its great phosphorescence. The materials studied in the first year of this research focused on the emission properties of CaZnOS crystals singly doped with Terbium and co-doped with Terbium and Europium. By studying the optical properties and the kinetics of recombination with time-resolved luminescence, the de-excitation mechanisms and the charge transfer processes have been established. A fundamental role is played by the defective centers and their efficient energy transfer process to the excited levels of Terbium, the mechanism being also active among co-doping rare earths (from Tb3+ to Eu3+), allowing further tuning of the emission properties. The second year centred on optimizing the mechano-luminescent properties of CaZnOS: Tb using microwave-assisted synthesis (MAS) method. The results were compared with samples obtained through conventional solid-state methods. The analysis of the material's characteristics was accomplished using various techniques to investigate their structural, morphological, and optical properties. A detailed study of the material's mechanoluminescent properties was done through single impacts with varying energies. The comparison of the microwave and conventional solid-state synthesis methods highlights the potential of microwave-assisted methods to optimize the properties of mechano-luminescent materials for practical applications. The third-year activity was done with CGO a long persistent luminescent phosphor (LPLP). The study involved careful synthesis and characterization of Ca3Ga4O9: xBi3+, yZn2+, zTb3+ phosphors doped with different levels of Tb3+ ions. The aim of the investigation was to acquire an intense conception of the influence of Tb3+ doping on the optical and structural properties of the material. overall, this study provides a comprehensive insight into the properties of long-persistent phosphors and demonstrates their potential for various technological applications, including optical data storage. Generally, the study in this research with the different host materials such CaZnOS and Ca3Ga4O9 and methods was done to adequately fulfil the requirements of the European Commission (EU) on this research by applying little amount of the rare-earth dopants such as (Tb3+ Eu3+), for engineering, and construction of eco-friendly and sustainable new phosphors for photonics applications and develop new experimental methods to optimize the industrialization of photonic materials to decrease energy consumption.