Morphology-controllable synthesis of LaOF:Ln3+ (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 379 nm. These results show this material may have potential applications in field-emission displays. [ABSTRACT FROM AUTHOR]