Transparent sol-gel glass ceramics containing β-NaYF₄:Yb³⁺/Er³⁺ nanocrystals: Structure, upconversion luminescent properties and optical thermometry behavior

Transparent bulk glass ceramics (GCs) containing β−NaYF₄:Yb³⁺/Er³⁺ upconversion nanocrystals were successfully prepared via a new sol-gel route for the first time. The structure, composition and morphology of the as-fabricated glass ceramics are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which confirm the segregation of β-NaYF₄ nanocrystals in silica glass matrix with the maintenance of their crystalline phase and microstructure. More significantly, intense upconversion (UC) emissions can be realized for Yb³⁺/Er³⁺ co-doped glass ceramics by profiting from low-phonon-energy environment of erbium ions in β-NaYF₄ nanophase. Furthermore, temperature-dependent UC emission performance of the present GC is systematacially investigated to explore their potential application in optical thermometry. Obviously, owing to intense UC emissions of β−NaYF₄:Yb³⁺/Er³⁺ nanocrystals and high transparency, superior chemical/mechanical stability of oxide glassy matrix, the as-fabricated GCs exhibit good temperature sensing performance and good thermostability for precise temperature detecting. It is expected that the preliminary research can give a reference for designing new transparent bulk GCs and may exploit a valid method for developing high-performance optical temperature sensors.