Bifunctional highly fluorescent hollow porous microspheres made of BaMoO4: Pr3+ nanocrystals via a template-free synthesis

We report a bifunctional hollow porous microsphere composed of single-component BaMoO4 : Pr3+ nanocrystals by a facile template-free synthesis. All the as-synthesized hollow microspheres are well-dispersed with a diameter of 2-4 mu m and the BaMoO4 : Pr3+ nanocrystals measure 30-60 nm in diameter. It is observed that there are a large amount of pores with an average diameter is 17.5 nm in the shell of these BaMoO4 : Pr3+ hollow microspheres, thereby exhibiting a great promise for drug delivery. Meanwhile, the strong, narrow-bandwidth red emission centered at 643 nm from these nanostructures can be efficiently excited from 430 nm to 500 nm. The combination of excellent luminescent properties and a hollow porous nanostructure suggest a great promise in the application of these nanostructures in lighting and displays, and in biomedicine such as targeted drug delivery, integrated imaging, diagnosis, and therapeutics. In addition, the template-free solution synthesis can be applied to the design and fabrication of other functional architectures.