A novel and easy synthesis pathway to synthesize small ZnO nanoparticles with a narrow size distribution is reported. The synthesis implies the simple dissolution of a zinc carboxylate hydrated salt (cyclohexanebutyrate or acetate) in a polar basic aprotic solvent as dimethyl sulfoxide (DMSO) or N,N‘-dimethylformamide (DMF) at room temperature. It is necessary to control the water content and temperature to ensure the reproducibility. The hydrolysis of zinc carboxylates allows the formation of ZnO nanoparticles of different sizes, depending on reaction conditions. Solvent basicity and the interaction of DMSO−H2O play crucial roles on the hydrolysis mechanism. The stability and the optical properties of the ZnO colloids were monitored by UV−visible electronic absorption and emission spectroscopies. From an HR-TEM study it was established that low concentration (2 × 10-4 M) of zinc cyclohexanebutyrate and zinc acetate afforded ZnO nanocrystallites of (2.12 nm, SD = 0.76) and (3.0 nm, SD = 0.5), average size, respectively. ZnO nanocrystals with rock salt structure coexist with wurtzite structure when zinc cyclohexanebutyrate is used as the starting salt. Dynamic light backscattering size measurements of ZnO nanoparticles were accomplished in DMSO colloid dispersions, resulting in the detection of small individual nanoparticles and assemblies of nanoparticles. Powder X-ray diffraction spectroscopy was used to accomplish the nanoparticle characterization, of DMF dispersions. Experimental results show that cyclohexanebutyrate acts as a more effective capping agent than acetate. Low concentration (2 × 10-4 M) colloidal ZnO dispersions in DMSO did not show any flocculation or red shift in two months, probably due to the concatenated dynamic stabilizing action of carboxylate ions and solvent molecules. The ZnO colloids in DMF are not stable and readily precipitate; moreover, nanoparticles in this solvent tend to adhere to glass walls, which allows production of ZnO films.

No abstract

In the present work the synthesis of C₆₀ produced in a conventional microwave oven from the decomposition of camphor resin is reported. The polycrystalline structure of the sample was determined by X-Ray Diffraction (XRD), the sample showed several phases, the main phase corresponds to fullerene C₆₀ ordered in a Face-Centered Cubic structure (FCC), with two more structures: one orthorhombic system and the other the monoclinic system coexisting also with graphite 2H phase. It was observed in a Scanning Electron Microscopy (SEM), that the sample formed thin films of stacked carbon. Whereas in a High Resolution Transmission Electron Microscopy (HRTEM), measurements in Bright Field mode revealed that the main phase of the material is C₆₀ ordered in FCC structure and the elemental composition and atomic bonding state can be determined by analyzing the energy with the electron microscope by Elesctron Energy- Loss Spectroscopy (EELS), technique allowed confirm all the phase C₆₀ established with XRD observations

No abstract

In the present work the synthesis of fullerene thin film produced in a conventional microwave oven from the decomposition of terpenoid is reported. The polycrystalline structure of the sample was determined by X-ray diffraction (XRD); the sample showed several phases, and the main phase corresponds to fullerene ordered in a face-centered cubic structure (FCC), with a lattice parameter a=14.16 Å, with two more structures: one is orthorhombic system with lattice parameters a=9.53 Å, b=8.87 Å, and c=8.354 Å, and the other is the monoclinic system with lattice parameters a=10.24 Å, b=7.80 Å, c=9.49 Å, and β=92.4° coexisting also with graphite 2H phase with lattice parameters a=2.46 Å, c=6.71 Å. It was observed in a scanning electron microscopy (SEM) that the sample formed thin films of stacked carbon. The film thickness was measured by a SEM, and it was 140.8 to 523 nm and the macroscopic area of 12 cm2, whereas a high-resolution transmission electron microscopy (HRTEM) revealed that the main phase of the material is C60 ordered in a face-centered cubic structure (FCC). In the sample surface by atomic force microscopy (AFM), islands deposited crystals were observed having symmetry 4-3m crystal habit associated with the tetrahedron.