Synthesis and optical properties of water-soluble fluoride nanophosphors co-doped with Eu3+ and Tb3+

The synthesis, structure and optical properties of water-soluble fluoride nanophosphors co-doped with Eu3+ and Tb3+ are presented. Nanocrystals of NaYF4 were synthesized via a hydrothermal microwave-assisted technique. XRD, TEM, AFM, FTIR as well as photoluminescence (PL) spectra were used to characterize the doped nanocrystals. The average size of nanocrystals, determined from XRD, AFM and TEM measurements, was ca. 28 nm. It was found that energy transfer occurs between Tb3+ and Eu3+ ions embedded in NaYF4 matrix, both in nanocrystals dispersed in chloroform and those in aqueous solution. We demonstrate that this simple colloidal system possesses the essential features required for both energy transfer and potential application in biolabeling.

► Synthesis, structure, morphology and optical properties of water-soluble fluoride nanoparticles with co-doped Tb3+ and Eu3+ are presented.
► We show that the amount of RE3+ ions incorporated into NaYF4 NCs influenced their size, shape and crystallographic structure; nanocrystals with the surface ligand exchanged to hydrophilic were easily dispersed in water and exhibited good performance in gel electrophoresis; efficient excitation energy transfer from Tb3+ to Eu3+ ions took place in the NaYF4 matrix.
► Water-soluble nanocrystals fabricated in a one-pot synthesis can perform as alternative luminescent bioprobes.