Two-step synthetic route towards monodisperse vernier yttrium oxyfluoride with multicolour fluorescence

Abstract

A two-step synthetic route (Y2(OH)5Cl·1.5H2O → Y(OH)xF3-x → Y6O5F8) was designed to prepare monodisperse orthorhombic Y6O5F8 (denoted as V-YOF) for the first time. In this approach, Y2(OH)5Cl·1.5H2O was employed as precursor to synthesize Y(OH)xF3-x via the ion exchange reaction. The morphologies, structures and photoluminescence properties of samples were investigated by XRD, SEM, FT-IR, EDS and PL spectra. Under ultraviolet light excitation, the V-YOF:Ln3+ (Ln = Eu, Tb) phosphors show strong light emissions with different colors for different doping ions. Moreover, by co-doping the Tb3+ and Eu3+ into V-YOF host, multicolor tunable emissions are obtained due to the energy transfer from Tb3+ to Eu3+ (a dipole-dipole interaction mechanism). And by the calculation, the energy transfer efficiency of V-YOF:0.05Tb3+, xEu3+ can reach up to 61.24% when the concentration of the Eu3+ is 0.05. The fluorescence lifetime at this condition is 1.00 ms. These features manifest this material may have potential applications for field-emission displays.