Tuning the crystalline phase and morphology of the YF3:Eu3+ microcrystals through fluoride source.

A series of Eu3+-doped pyridine functionalized YF3 microcrystals were synthesized at low temperature (70 °C) using a simple colloidal route. The shape and phase of the YF3 microcrystals were tuned using different fluoride sources (e.g. NaF, NaBF4 and NH4F). Cubic phase of the microcrystals with flower like morphology was achieved with NaF as fluoride source, while use of NaBF4 and NH4F led to the formation of orthorhombic phase with bundle and rice flake like morphology, respectively. This difference in the morphology and phase is reflected in their optical properties as well. A mechanism has been proposed for the formation of different morphology of YF3 microcrystals. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrum (FTIR), photoluminescence (PL) and lifetime measurements were used to characterize the structural and optical properties of microcrystals. [ABSTRACT FROM AUTHOR]