Fluorescent magnetic nanocrystals by sequential addition of reagents in a one-pot reaction: a simple preparation for multifunctional nanostructures.
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.
Gao
Jinhao
J
Department of Chemistry, Graduate Program of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Zhang
Bei
B
Gao
Yuan
Y
Pan
Yue
Y
Zhang
Xixiang
X
Xu
Bing
B