Effect of crystal structure and ions concentration on luminescence in Yb3+ and Tm3+ codoped fluoride microcrystals

A facile hydrothermal method is used for the preparation of Tm3+/Yb3+ codoped fluoride microphosphors. The effect of crystal structure and ions concentration on the spectra and lifetimes of the radiative levels of Tm3+ ions in the different fluoride microcrystals is studied in detail. XRD analysis of Tm3+/Yb3+ codoped LaF3 microcrystals shows that 20% Yb3+ doping is sufficient for hexagonal LaF3 microparticles to crystallize completely in the orthorhombic phase. And lifetime analysis suggests that the average lifetimes of the radiative levels of Tm3+ ions increased when the matrix phase structure changing from orthorhombic phase to hexagonal phase with ytterbium dopant concentration changing.