YF3:Eu3+ Micro-Single Crystals: Fine Morphological Tuning and Luminescence Properties

Uniform YF3:Eu3+ micro-single crystals with diamond-like, truncated octahedral, and octahedral morphologies have been synthesized by adjusting the molar ratio of KF/Y(NO3)(3) and the amount of dilute HNO3 through a facile hydrothermal route without using any morphology controlling agent. It has been found that the excess K+ ions favor for the formation of {111} facets. The morphological evolution has been presented on the basis of a series of time-dependent experiments, from which a truncating growth mechanism has been proposed. Besides, the investigation on morphology-dependent luminescence properties reveals that the as-obtained truncated octahedral samples exhibit the strongest orange-red emission, while the intensity of diamond-like ones is the lowest