Development of synthesis strategies for efficient, robust, and stable light - emitting nanocomposites based on halide perovskites

Over the past few years, halide perovskites have generated extensive interest as potential materials for various applications, such as light-emitting diodes, displays, detectors, and tracking (e.g., bio-applications or oil tracing). However, the effective implementation of these halide perovskite NCs in industrial manufacturing processes is limited by their poor stability under various conditions: when exposed to humidity, high temperature, and photo-irradiation, the NCs quickly degrade. Therefore, the research work included in this thesis is mainly focused on developing various strategies to improve the stability of halide perovskite NCs with the aim of implementing them in practical applications. Among different matrix encapsulation materials for perovskites (such as polymers, inorganic metal oxide/halides, and metal-organic framework), silica has been chosen as an efficient matrix to protect halide perovskite NCs due to its excellent properties, which include high optical transparency in the visible, chemical stability, abundance, non-toxicity, and low-cost. Two novel approaches to produce CsPbX3 NCs embedded in silica are developed as simple and straightforward methods via sol-gel route and molten salt synthesis. The resulting composites are investigated on structure, optical properties and their stability against environment conditions. As a proof of concept, these composites are also tested in some application such as down-converter phosphors in light-emitting diode and tracer in oil industry. In an addition work, the structure and optical properties of Sn-based perovskite materials, which are synthesized by hot-injection method, are also discussed, extending the scope of this thesis to non-toxic lead-free perovskite materials.