Controllable Synthesis of Mn Doped Nanoparticles by a Facile Anion Exchange Method.

Fluorescence imaging in the second near-infrared window (NIR-II, 1000-1400 nm) is attracting extensive attention. Mn doped BaSO with broadband emission from 900 nm to 1400 nm is emerging as a new class of NIR phosphor for fluorescence imaging. Manganese has diverse valence states, thus it is difficult to prevent valence change of Mn during traditional synthesis process. In this work, BaSO:Mn nanoparticles with uniform size and morphology were first successfully prepared through a fast liquid-solid solution route at room temperature. The nanoparticles exhibit broadband NIR emission from Mn when excited by 808 nm lasers. This convenient strategy, based on an efficient anion exchange reaction, is proved effective for synthesizing nano-sized materials. The results reveal that our strategy has great potential in fabricating special valence state ion doped nanomaterials.