Solution synthesis and characterization of quantum confined Ge nanoparticles

A solution synthesis of crystalline Ge nanoparticles (nc-Ge) is reported. The metathesis reaction of NaGe with excess GeCl₄ in glyme solvents produces nc-Ge. Metathesis reactions between KGe and excess GeCl₄ or GeCl₂:(dioxane) in glyme and Mg₂Ge and excess GeCl₄ in diglyme and triglyme were also investigated. The surface of these nanoparticles is terminated with alkyl groups by reaction with alkyl Li and Grignard reagents. The alkyl-terminated crystalline Ge nanoparticles (R̂-nc-Ge) were characterized by Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy, powder X-ray diffraction, UV-vis absorption spectroscopy, photoluminescence, and photoluminescence excitation spectroscopy. The optical properties of R̂-nc-Ge made by this method agree with predictions from quantum confinement models.