Project G – Formulation and Crystallization of Perovskite Bearing Glass-Ceramics for Light Management

Glass-ceramics are an important material class due to their versatile mechanical and thermal properties that are interesting for a number of applications. Importantly, they have the ease of preparation of glasses and the properties of the embedded crystals. In addition, novel perovskite-based crystals have also been shown to have high electrooptical conversion efficiency as well as electromechanical coupling. Development of glass-ceramics embedded with such functional crystalline particles is very attractive for various electrooptical and electromechanical energy harvesting applications. Previous investigations, for example, have demonstrated ferroelectric glass- ceramics with a piezoelectric coupling on the order of ~10 pC/N using various perovskite materials, such as BaTiO3, LiNbO3, and LiTaO3. These ferroelectric materials, however, display a relatively small electromechanical coupling. Novel lead-free ferroelectrics have demonstrated significantly larger piezoelectric and ferroelectric response, making them attractive in glass-ceramics for electromechanical energy conversion systems. In addition, through the insertion of rare earth elements (REE), which can be readily hosted on the crystallographic sites of the perovskite crystal structure, the photoluminescent properties can be controlled. This is particularly important for light conversion, which can be integrated in photovoltaic devices to increase efficiency. Perovskite bearing glass ceramics have been to-date only attempted for a narrow range of compositions and applications.
The focus of this project will be on the synthesis and processing of glass-ceramics containing REE doped lead-free perovskites for electrooptical and electromechanical systems as well as the characterization of their optical and piezoelectric properties. This goal will be achieved by a deep understanding of atomic local environments and the use of different synthesis route to control atomic clustering and, therefore, the nucleation stage and the final crystals shapes and orientations.

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