Controlled synthesis of uniform Na_xScF_{3+ x} nanopolyhedrons, nanoplates, nanorods, and nanospheres using solvents

Na_xScF_3+x nanocrystals with controllable shapes were synthesized in the oleic acid/1-octadecene (OA/OD) coprecipitation reaction system. By adjusting the volume ratio of the solvents, well-defined Na_xScF_3+x nanopolyhedrons, nanoplates, nanorods, and nanospheres with different sizes and phases could be selectively obtained. The as-prepared Na_xScF_3+x nanocrystals were well characterized and investigated. Based on the results obtained, it was found that the solvents influenced significantly the growth process of the Na_xScF_3+x nanocrystals. A change in the nucleus formation rate and the responsible crystal planes leads to different morphologies of the resulting nanocrystals. Further investigation on the upconversion (UC) luminescence of the Yb/Er codoped Na_xScF_3+x nanocrystals showed that Na_xScF_3+x nanostructures could serve as host matrices to give strong UC luminescence. In addition, their different phases and morphologies were responsible for the diverse luminescence intensity.