Ultrathin yttrium fluoride nanostructures: Controlled synthesis and polarized up-conversion emission property

Ultrathin nanomaterials are very significant members of the nanocrystalline material family because of their unique properties of broad significance. In the present study, highly uniform atomically thick YF₃ nanobelts and nanowires are fabricated by using an oleylamine assisted colloidal chemical strategy. Reaction monitoring demonstrates that two-dimensional lamellar assemblies of YF₃ clusters are vital intermediates in the growth process, which transform to ultrathin nanobelts and nanowires depending on the heating temperature. This approach can be readily extended to produce ultrathin structures of other lanthanide fluoride (ErF₃, YbF₃, TmF₃, NdF₃, and LaF₃) systems. The polarized upconversion emission of Yb³⁺/Er³⁺ co-doped YF₃ is demonstrated for a domain of a perfectly aligned assembly of parallel ultrathin nanowires. The polarization degree of green, red and infrared emission peaks are 0.32, 0.28 and 0.50, respectively.