Nanocrystalline intermetallic compounds show promise in several applications, however chemical methods giving phase purity and size control are lacking. Using metal precursors previously developed for atomic layer deposition but rarely explored for solution-phase materials synthesis, we demonstrate the synthesis of several phase-pure transition metal alloys including the full library of MSn<sub>2</sub> and MSb (M = Cr, Mn, Fe, Co, Ni) with control over phase and stoichiometry, several of which are reported for the first time in nanocrystalline form. For stannides, the synthesis of which occurs above the melting point of Sn, the alloys formation progresses via an intermediate stage of small Sn<sup>0</sup> nanocrystals stabilized by the strongly-binding amidinate ligands with subsequent diffusion of transition metal atoms into tin. We find that for metals with higher melting temperatures than Sn (such as Sb), the reductant injection temperature determines the phase purity of the intermetallic product. Temperature-dependent magnetic properties of the intermetallic nanocrystals have been studied, and the effect of annealing the nanocrystals at high temperatures on crystallinity is also explored.

Metal amidinate precursors for general solution-phase synthesis of intermetallic nanocrystals

2019 Spring National Meeting

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