The covalent combination of rare earth up-conversion nanorods and a rhodamine derivative: An “off-on” Hg(II) sensing system with high selectivity

- An “off-on” Hg(II) sensor owing high selectivity was constructed.
- Up-conversion NaYF4:Yb3+/Er3+ was used as the excitation core.
- A rhodamine derivative was grafted onto the surface of the excitation core.
- The nanocomposite was carefully characterized and analyzed.
- Linear response towards Hg(II) and good photostability were observed.