The single-band red upconversion luminescence from morphology and size controllable Er3+/Yb3+ doped MnF2 nanostructures

Abstract

Er³⁺/Yb³⁺ doped MnF₂ nanostructures have been prepared via a solvothermal method. The morphology of the nanocrystals could be well controlled from nanoparticles to nanoclusters and nanolanterns by varying the volume ratio between oleic acid and ethanol in the solvent. Moreover, the size is tuned from 200 nm to 1.5 μm with the increase of reaction temperature from 110 to 200 °C. It is shown that controlling the doping concentration (Yb³⁺ ≤ 20 mol%) is essential to preserve the single phase and morphology of the MnF₂ host. Single-band red upconversion (UC) emission can be generated in Er³⁺ single and Er³⁺/Yb³⁺ codoped MnF₂ nanoclusters due to the energy transfer between host Mn²⁺ and dopant Er³⁺ ions. The detailed studies suggest that our MnF₂:Er³⁺/Yb³⁺ nanocrystals have the strongest single-band luminescence feature at the dopant concentrations of Er³⁺ (2 mol%) and Yb³⁺ (20 mol%). The brighter red emission from the current nanostructure compared with those from NaYF₄:Er³⁺/Yb³⁺ has shown its suitability as an efficient UC luminescence host. It is expected that the achieved intense pure red emission may have potential application in in vivo bioimaging.