Nano-Crystallization of Ln-Fluoride Crystals in Glass-Ceramics via Inducing of Yb(3+) for Efficient Near-Infrared Upconversion Luminescence of Tm(3+)

Transparent glass-ceramic composites embedded with Ln-fluoride nanocrystals are prepared in this work to enhance the upconversion luminescence of Tm(3+). The crystalline phases, microstructures, and photoluminescence properties of samples are carefully investigated. KYb(3)F(10) nanocrystals are proved to controllably precipitate in the glass-ceramics via the inducing of Yb(3+) when the doping concentration varies from 0.5 to 1.5 mol%. Pure near-infrared upconversion emissions are observed and the emission intensities are enhanced in the glass-ceramics as compared to in the precursor glass due to the incorporation of Tm(3+) into the KYb(3)F(10) crystal structures via substitutions for Yb(3+). Furthermore, KYb(2)F(7) crystals are also nano-crystallized in the glass-ceramics when the Yb(3+) concentration exceeds 2.0 mol%. The upconversion emission intensity of Tm(3+) is further enhanced by seven times as Tm(3+) enters the lattice sites of pure KYb(2)F(7) nanocrystals. The designed glass ceramics provide efficient gain materials for optical applications in the biological transmission window. Moreover, the controllable nano-crystallization strategy induced by Yb(3+) opens a new way for engineering a wide range of functional nanomaterials with effective incorporation of Ln(3+) ions into fluoride crystal structures.