Fluorescent Magnetic Nanocrystals by Sequential Addition of Reagents in a One-Pot Reaction: A Simple Preparation for Multifunctional Nanostructures
journal contributionposted on 03.10.2007 by Jinhao Gao, Bei Zhang, Yuan Gao, Yue Pan, Xixiang Zhang, Bing Xu
Any type of content formally published in an academic journal, usually following a peer-review process.
Core−shell nanostructures consisting of FePt magnetic nanoparticles as the core and semiconducting chalcogenides as the shell were synthesized by a series of reactions in a one-pot procedure. Adding Cd(acac)2 as the cadmium precursor to a reaction mixture containing FePt nanoparticles afforded FePt@CdO core−shell intermediates. The subsequent addition of chalcogens yielded FePt@CdX core−shell nanocrystals (where X was S or Se). The reverse sequence of addition, i.e., adding X before Cd, resulted in spongelike nanostructures because the chalcogens readily formed nanowires in the solution. Transmission electron microscopy, energy-dispersive X-ray spectrometry, selected area electron diffraction, fluorescence spectroscopy, and SQUID were used to characterize the nanostructures. These core−shell nanostructures displayed superparamagnetism at room temperature and exhibited fluorescence with quantum yields of 2.3−9.7%. The flexibility in the sequence of addition of reagents, combined with the compatibility of the lattices of the different materials, provides a powerful yet convenient strategy for generating sophisticated, multifunctional nanostructures.