Hydrothermal synthesis and luminescence properties of hierarchical SrF2 and SrF2:Ln3+ (Ln = Er, Nd, Yb, Eu, Tb) micro/nanocomposite architectures

Highly uniform SrF2 and SrF2:Ln3+ (Ln = Er, Nd, Yb, Eu, Tb) hierarchical microspheres assembled by 2D nanoplates have been successfully synthesized by a facile and friendly hydrothermal route. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectra were used to characterize the samples. The experimental results indicate that reaction time and chelating reagent play a key role in forming the hierarchical microspheres. The formation mechanism was proposed based on the evolution of this morphology as a function of hydrothermal time. The near-infrared luminescence of lanthanide ions (Er, Nd, and Yb) doped SrF2 microspheres were discussed in detail. In addition, the as-obtained SrF2:Eu3+ sample exhibits orange-red emission centered at 590 nm under excitation at 393 nm, while the SrF2:Tb3+ exhibits a strong green emission at 540 nm. The as-synthesized SrF2:Ln3+ luminescent microspheres might find some potential applications in areas of photoluminescence, telecommunication and laser emission.