Synthesis and luminescent properties of oleic acid (OA)-modified CaF2: Eu nanocrystals

The OA-modified CaF2: Eu nanocrystals that can be well dispersed in chloroform to form a clear solution were synthesized and characterized. The nanocrystals have a roughly spherical shape with particle diameter of about 10 nm. Possible mechanism was proposed to explain the growth process. Upon the excitation at 395 nm, the room-temperature emission spectrum of the nanocrystals in chloroform presents the characteristic transitions 5D0→7FJ of Eu3+ ions, with 5D0→7F2 (610 nm) transition as the most prominent group. The luminescence decay of Eu3+ ions in CaF2 nanocrystals was also investigated and two luminescence lifetimes of 737 μs (11.2%) and 2.08 ms (88.8%) were obtained.