Shape controllable synthesis and multicolour fluorescence of lanthanide doped Vernier yttrium oxyfluoride

A series of Tb 3+ and Eu 3+ activated orthorhombic yttrium oxyfluoride, Y 7 O 6 F 9 (denoted as V-YOF hereafter) phosphors were synthesized through a facile two-step hydrothermal synthesis route followed by heat treatment for the first time. The phase, morphologies, sizes and photoluminescence properties of as-prepared samples were investigated by means of XRD, SEM, and luminescence spectroscopy. A series of characteristic emission originated from the f–f transitions of Eu 3+ and Tb 3+ can be observed and multicolour emissions from green to yellow and then to red have been achieved in the V-YOF:Tb 3+ ,Eu 3+ samples under 378 nm irradiation. The energy transfer process from Tb 3+ to Eu 3+ was studied and demonstrated to be a quadrupole–quadrupole interaction mechanism. These results show that the V-YOF phosphors have potential applications in field-emission displays.