Morphology-controlled hydrothermal synthesis and multifunctional luminescence properties of micro-crystals Gd6O5F8:Eu3+/Tb3+/Tm3+

This paper reports on a facile hydrothermal route that has been developed to synthesize a precursor Gd(OH)(2.14)F-0.86 and a novel phosphor host Gd6O5F8. The morphology of the micro-sized Gd(OH)(2.14)F-0.86/Gd6O5F8 can be easily tuned in a controlled manner by altering the fluorine sources, alkali solutions, reaction time and the pH values of the initial solution. Under ultraviolet (UV) light, vacuum ultraviolet (VUV) light and low-voltage electron beam excitation, the Gd(OH)(2.14)F-0.86/Gd6O5F8:Ln(3+) (Eu, Tb and Tm) samples show the characteristic f-f transitions of the Ln(3+) ions and give bright red, green and blue emissions, respectively. The results prove that the as-synthesized Gd6O5F8 are excellent host lattices for rare earth luminescence, which may find potential applications in solid-state light, field emission displays (FEDs).