A simple and efficient method for the synthesis of water-soluble NdF3 and NdF<sub>3</sub>:Ba<sup>2+</sup> nanocrystals under hydrothermal conditions is established. The method involves the coating of the nanocrystals with a layer of hydrophilic polymer polyvinylpyrrolidone (PVP). The as-prepared products are characterized by powder X-ray diffraction, field emission scanning electronic microscopy, Fourier transform infrared spectroscopy, and photoluminescence spectroscopy. The PVP coating transforms the nanocrystals into a biocompatible material and improves the fluorescence intensity of NdF<sub>3</sub> in the near infrared (NIR) region. The morphology of the nanoparticles changes, whereas the fluorescence intensity of NdF<sub>3</sub> in the NIR region increases when a small amount of Ba<sup>2+</sup> is doped into the NdF<sub>3</sub>/PVP nanoparticles.
© 2012 Chinese Optics Letters
Ting Fan, Qinyuan Zhang, and Zhonghong Jiang, "Enhanced near infrared emission in water-soluble NdF3 nanocrystals by Ba2+ doping," Chin. Opt. Lett. 10, 021602- (2012)