NaGdF4:Ce3+ and (Ce,Gd)F-3 nanoparticles have been prepared by using a hydrothermal procedure. The hexagonal NaGdF4:Ce3+, cubic NaGdF4:Ce3+, or (Ce,Gd)F-3 nanoparticles could be synthesized by controlling different molar ratio of reactants and synthesized temperatures. The emission spectra of the Ce3+ ions in the hexagonal NaGdF4:Ce3+ nanoparticles consisted of two broad bands at 360 nm and 524 nm. Only one broad emission band at 360 nm can be observed in the cubic NaGdF4:Ce3+ nanoparticles and the (Ce,Gd)F-3 nanoparticles. The lifetimes of 360 nm emissions of Ce3+ ions varied from nanoseconds at 300 nm excitation to microseconds at 260 nm excitation due to an efficient energy transfer from the Gd3+ ions to Ce3+ ions. (C) 2010 Elsevier B.V. All rights reserved.