Investigation of Reaction Conditions for Optimal Germanium Nanoparticle Production by a Simple Reduction Route

Various reaction conditions, such as reductant, time, procedure, concentration, and temperature, were investigated with the aim of finding a simple, optimized synthetic route for the synthesis of crystalline germanium nanoparticles. Results from these studies indicate that sodium naphthalide is an ideal reductant and that the reaction is virtually complete within 10 min. Furthermore, it was observed that a two-pot synthesis resulted in a cleaner, narrower distribution of nanoparticle size and that the narrowest size distribution (∼20%) was produced when a dilute Na(naphth) in glyme mixture was utilized. The optimum initial reduction temperature was found to be 0 °C. It was also shown that concentration and temperature play an important role in controlling nanoparticle size. The best reaction conditions, as stated above, produced nanoparticles with a size dispersion of ∼20% when combined. Transmission electron microscopy (TEM), selected-area electron diffraction (SAED), high-resolution TEM (HRTEM), energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), and chemical analysis were used to characterize the nanoparticles.