Modifying crystal phase, shape, size, optical and magnetic properties of monodispersed multifunctional NaYbF4 nanocrystals through lanthanide doping

Abstract

In this paper, a simple lanthanide (Ln) doping route for modifying the crystal structure including crystal phase, shape, size and physics properties such as up conversion (UC) and magnetic properties of monodisperse multifunctional NaYbF₄ nanocrystals is demonstrated. The results revealed that the crystal phase transformation from cubic to hexagonal phase, shape evolution from one-dimensional (rods) to zero-dimensional (nanoparticle) and size transition from microscale to nanoscale can be readily tuned. Moreover, these nanocrystals doped with different Gd³⁺ concentrations exhibit multi-functionality, including tunable UC emissions colours and paramagnetic properties, which making them potentially applicable in the biological field as biolabels, bioseparation, magnetic resonance imaging (MRI), and optical-magnetic dual modal nanoprobes in biomedical imaging. It is also expected that the doping-induced structure and physical properties transformation can be applied to other NaLnF₄ nanocrystals.