NaY(MoO4)2 microcrystals with controlled faceting and their tunable photoluminescence properties after doping with Eu3+

Abstract

We present a facile synthesis of NaY(MoO₄)₂ microcrystals with controlled morphologies and tunable faceting via an ethylenediaminetetraacetic acid (EDTA)-mediated hydrothermal method. Three different types of NaY(MoO₄)₂ microcrystals, namely, sharp bipyramids, truncated bipyramids, and quasi-cubes, can be selectively produced, and the percentage of {001} and {101} facets in the tetragonal bipyramidal NaY(MoO₄)₂ microcrystals can be engineered through the judicious choice of an appropriate amount of EDTA. The preferential adsorption of EDTA on {001} facets of the NaY(MoO₄)₂ crystal is responsible for the morphology evolution of the NaY(MoO₄)₂ microcrystals from sharp bipyramids to quasi-cubes. The present synthetic approach is also extendable to achieve NaHo(MoO₄)₂ and NaTb(MoO₄)₂ microcrystals with different shapes and tunable exposed facets. It is found that the luminescence properties of the NaY(MoO₄)₂:Eu³⁺ microcrystals are highly dependent on their shape and size, and the sharp NaY(MoO₄)₂:Eu³⁺ bipyramids exhibit the strongest emission intensity due to their larger size, fewer defects and less exposed facets. As such, the sharp NaY(MoO₄)₂:Eu³⁺ bipyramids may have potential applications in light display systems as well as optoelectronic devices, while the present EDTA-mediated hydrothermal synthetic strategy represents a potentially general route to the generation of nano/microcrystals with shape- and exposed facet-control.