Shape-Controlled Synthesis of Monodispersed Ultrasmall CaGd3F11 Nanocrystals for Potential Dual-Modal Probes

摘要

The shape-controlled synthesis of monodispersed CaGd3F11 nanocrystals by means of a solvothermal method is reported for the first time. Their morphologies can be controlled to spherical nanoparticles and one-dimensional (1D) nanorods by tuning the volumes of oleic acid and octylamine in the reaction solution. Powder X-ray diffraction demonstrated their hexagonal crystalline structure. Transmission electron microscopy showed their ultrasmall sizes (sub-10 nm) and good monodispersity. The organic capping ligands on the CaGd3F11 surfaces were analyzed through infrared spectra and X-ray photoelectron spectroscopy. Also investigated is the influence of oleic acid and octylamine on the morphology of CaGd3F11 nanocrystals. Upconversion (UC) luminescence and magnetic resonance imaging (MRI) performance that depend on the shapes of as-prepared CaGd3F11 were studied further. CaGd3F11 nanoparticles and nanorods exhibited UC luminescence with green monochrome after doping with Yb3+ and Er3+ ions. The CaGd3F11 nanorods emitted a much higher UC intensity than the nanoparticles. The MRI relaxivity of CaGd3F11 nanorods was enhanced relative to that of nanoparticles.