Controlled Crystallization of Tb3+/Yb3+ Co-Doped Silica-Hafnia Glass-Ceramic films deposited by spin coating

A comprehensive understanding of the crystallization process of sol gel-derived glass-ceramics and glasses is crucial, being this process critical for the optical properties of these materials. In this study, we provide the X-ray Diffraction (XRD) investigation of Silica-Hafnia co-doped Tb3+/Yb3+ luminescent layers synthesized through the sol-gel route and deposited via spin coating technique as a function of temperature. Notably, the crystallization starts after a heat treatment of 1000 ◦C with an increase in the crystallinity and in the crystallite size by increasing the temperature. Furthermore, a direct correlation between temperature-induced turbidity and crystallite radius was observed, which makes the samples grown at 1000 ◦C as transparent as those grown at lower temperature, surpassing 80 % transmittance. The materials’ remarkable degree of transparency designates them as exceptionally viable contenders for implementation as light concentrators in photonic applications.