Group four semiconducting nanoparticles (NPs), such as Germanium (Ge) are gaining increasing interest in energy related fields, such as nanostructured electrodes for lithium ion batteries. This is due to the combination of the favorable intrinsic properties with those arising from the nanoscale dimensions. Herein, we investigate a synthesis that combines sulfur with organometallic Ge(IV) precursors to form Ge NPs at relatively low temperatures (300 °C). We have examined the effects of solvent, sulfur concentration, and organogermanium halide precursor in order to gain insight into the reaction mechanism and our ability to control the kinetics of this synthesis. It was found that this reaction uses sulfur in conjunction with primary amines to form H<sub>2</sub>S <i>in-situ</i> as the reducing agent. We were able to form either crystalline or amorphous material by choosing an appropriate amine as solvent, and control the NPs diameter by changing the sulfur concentration. The importance of the disproportionation of Ge(II) species to Ge(0) and Ge(IV) is also discussed, identifying the halogen cleavage from the precursors as the rate determining step. The synthetic details were followed via NMR, and IR spectroscopies. We determine the morphologies through TEM, Raman, and UV-Vis spectroscopy. From this information it was possible to propose a reaction mechanism and discuss our results with the aim to resolve the underlying dynamics and the system behavior, towards full control of the morphology of group IV nanomaterials.

Crystallinity and size control of colloidal germanium nanoparticles from organogermanium halide reagents

2019 Fall National Meeting

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