Synthesis and characterization of gallium colloidal nanoparticles

In this work, gallium colloidal nanoparticles (Ga-Nps) were synthesized by chemical liquid deposition (CLD). This method involved the deposition of metallic atoms with organic solvents (THF, acetone and 2-propanol) in a freezing matrix of the solvent at 77 K, in order to obtain core–shell Ga-Nps which were characterized by: FT-IR, UV–Vis, TEM, SAED and electrophoretic mobility measurements. TEM images revealed a wide distribution of the apparent size of the particles and apparent average size of 5.65, 8.11 and 13.87 nm for Ga-Nps obtained with 2-propanol, THF and acetone, respectively. UV spectra showed absorption bands of metal plasmons, interesting quantum size effects and plasmon absorption bands of particles aggregated to λ280 and λ325. Electrophoretic mobility allowed to evidence that nanoparticles had a negative charge as well as to observe that the zeta potential of the colloidal dispersions decreased over time, showing a significant tendency to the aggregation of Ga-Nps. The importance of the functionalization of metal nanoparticles with high dielectric constant solvents in the stabilization of colloidal systems was also observed. FT-IR spectroscopy revealed that the interaction of Ga surface with the solvent possibly produces a (GaC) bond. Experimental details, structural and thermal stability studies were also analyzed in this work.

Top view of the reactor metal atoms at the co-deposition. Reactor after the nucleation process. Collecting flask containing the final Ga colloid obtained after the matrix freezing process. Yellow Ga colloids for all solvents used (acetone, 2-propanol and THF) were obtained.Figure optionsDownload high-quality image (66 K)Download as PowerPoint slide