Morphology-controllable synthesis, energy transfer and luminescence properties of Ce3+/Tb3+/Eu3+-doped CaF2 microcrystals

CaF 2 :Ln 3+ (Ln = Ce, Tb, Eu) phosphors with highly uniform shapes have been successfully synthesized by a simple hydrothermal method directly. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) and lifetime. The results indicated that the pH values, organic additive and reaction time have a significant effect on the morphology and dimensions of CaF 2 microcrystals and the possible formation mechanism was also proposed. Furthermore, the energy transfer from Ce 3+ to Tb 3+ and from Tb 3+ to Eu 3+ and from Ce 3+ to Tb 3+ to Eu 3+ was observed and the corresponding mechanisms were discussed in detail. The CaF 2 :Ln 3+ phosphors may have potential optical applications in near-UV and violet LEDs.