X-ray luminescence of $LaF3:Tb3+$ and $LaF3:Ce3+,Tb3+$ water-soluble nanoparticles

We report x-ray luminescence from $LaF3:Ce3+,Tb3+$ and $LaF3:Tb3+$ water-soluble nanoparticles. The x-ray luminescence is dominated by emission from $Tb3+$ ions, similar to photoluminescence spectra of the nanoparticle aqueous solutions and spectra from nanoparticle powders precipitated from the aqueous samples. Coating the nanoparticles with an insulating inorganic $LaF3$ or organic $H2N–(CH2)10–COOH$ layer can enhance the x-ray luminescence from the aqueous nanoparticles. This enhancement is most likely due to the decreased energy loss due to the particle-solvent interactions.