A facile aqueous strategy for the synthesis of high-brightness LaPO4:Eu nanocrystals via controlling the nucleation and growth process

Ellipsoidal nanocrystalline LaPO4:Eu has been realized through an aqueous method by using microwave irradiation and microfluidic system. Through this method, we can control the nucleation and growth process. The as-prepared nanoparticles are pure monazite phase and water-dispersible and monodisperse, with a mean diameter of 4 nm and length of 6 nm. Luminescence data indicate the samples have a strong orange-red emission corresponding to 5D0→7F1 transition. Under the optimized conditions, the quantum yield is 21%. According to MTT assay, the nanoparticles are non-toxic materials and good biocompatibility. Therefore the LaPO4:Eu nanoparticles may possess the potential to serve as a luminescent bioimaging probe.