Morphology-controllable synthesis of LaOF:Ln(3+) (Ln=Eu, Tb) crystals with multicolor luminescence properties

In this paper, well defined LaOF crystals with multiform morphologies were first prepared via the urea-based precipitation method followed by a heat treatment. The morphologies of the LaOF samples, including nanospheres and nanorods, can be easily modulated by changing the fluorine sources. XRD, FT-IR, SEM, TEM, and emission spectra were used to characterize the prepared samples. Under ultraviolet excitation, the LaOF:Ln(3+) nanospheres display the characteristic f-f transitions of Ln(3+) (Ln=Eu, Tb) ions and give bright red, and green emissions, respectively. Furthermore, by codoping the Tb(3+) and Eu(3+) ions into LaOF host and varying the doping concentration of the Eu(3+) ions, multicolor tunable emissions have been obtained under the irradiation of 379nm. These results show this material may have potential applications in field-emission displays.