Controlled Synthesis of Uniform Na_<i>x</i>ScF_3+<i>x</i> Nanopolyhedrons, Nanoplates, Nanorods, and Nanospheres Using Solvents

Na_<i>x</i>ScF_3+<i>x</i> 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_<i>x</i>ScF_3+<i>x</i> nanopolyhedrons, nanoplates, nanorods, and nanospheres with different sizes and phases could be selectively obtained. The as-prepared Na_<i>x</i>ScF_3+<i>x</i> 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_<i>x</i>ScF_3+<i>x</i> 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_<i>x</i>ScF_3+<i>x</i> nanocrystals showed that Na_<i>x</i>ScF_3+<i>x</i> 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