Transparent oxyfluoride glass-ceramics obtained by different sol-gel routes

• Published in: Journal of sol-gel science and technology Vol. 102; no. 3; pp. 523 - 533
• Main Authors: Cruz, María Eugenia, Castro, Yolanda, Durán, Alicia
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-06-2022; Springer Nature B.V
• Subjects: Ceramics; Chemistry and Materials Science; Composites; Crystallization; Fluorides; Glass; Glass ceramics; Heat treatment; Inorganic Chemistry; Luminescence; Materials Science; Nanocrystals; Nanoparticles; Nanotechnology; Natural Materials; Optical and Electronic Materials; Optical properties; Oxyfluorides; photonic and optoelectronic applications; Review Paper: Sol-gel and hybrid materials for optical; Silica gel; Sol-gel processes; Sols; Structural analysis; Synthesis; Nanoparticles; oxyfluoride; rare-earth; glass-ceramics; sol-gel
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-022-05743-x

Oxyfluoride glass-ceramics (OxGC) present attractive optical properties suitable for many applications. The incorporation of fluoride crystals into silicate matrices improves the luminescence properties, producing materials appropriate for photonic applications. Many papers focus on the preparation of oxyfluoride glass ceramics by melting quenching (MQ), the most widely utilized process. However, in the last decades, the sol-gel process has gained increasing interest as an alternative method for avoiding the MQ drawbacks. The first sol-gel route for producing glass-ceramics with rare earth (RE) doped fluoride nanocrystals were based on the preparation and further mixing of two separate sols. The crystallization of the fluoride nanoparticles occurs during the controlled thermal treatment. More recently, a new sol-gel strategy was proposed, based on the previous synthesis of aqueous fluoride nanoparticles suspensions that are subsequently dispersed in a silica sol-gel matrix. This paper summarizes the most relevant results as well as the advantages and disadvantages of each route and their limitations for future industrial scale up. The synthesis routes are compared considering the structural and morphological characterization, elucidating the crystallization mechanisms, and evaluating the optical properties of the resulting materials. Particular attention is paid to the possibility of producing transparent oxyfluoride glass ceramics films with improved luminescence and enhanced optical properties.
Graphical abstract