RESUMEN
Cu(2)FeSnS(4) (CFTS) nanocrystals with tunable crystal phase have been synthesized using a solution-based method. As-synthesized CFTS nanocrystals in the shape of oblate spheroid and triangular plate with band gaps of 1.54 ± 0.04 and 1.46 ± 0.03 eV, respectively, appear attractive as a low-cost substitute for thin film solar cells.
RESUMEN
Nanocrystals and nanoclusters of the room-temperature magnetic spinel CuCr(2)S(4) have been synthesized using a facile solution-based method. The synthesis involves hot injection of an excess of 1-dodecanethiol (1-DDT) into a boiling coordinating solvent containing CuCl(2) and CrCl(3)·6H(2)O. Using octadecylamine (ODA) as a solvent yields cube-shaped nanocrystals with an average size of 20 ± 2 nm, while with oleylamine (OLA), nanoclusters with an average size of 31 ± 2.5 nm are obtained. In both cases, powder X-ray diffraction patterns confirmed the formation of the pure spinel phase without any impurities. While the synthesized powders are superparamagnetic near room temperature, they exhibit ferromagnetic behavior at lower temperatures, with magnetization (M(S)) values of 30 emu/g (1.63 µ(B)/f.u.) and 33 emu/g (1.79 µ(B)/f.u.) for the ODA- and OLA-capped nanocrystals and nanoclusters, respectively, at 5 K.
RESUMEN
Monodisperse CuInS(2) nanocrystals are produced by injecting mixed metal-oleate precursors into hot organic solvents containing the dissolved sulphur sources. A better understanding of the formation mechanism of CuInS(2) has enabled us to tailor anisotropic shapes in the form of triangular-pyramid, circular cone, and bullet-like rods with tunable crystal phases by varying the synthetic conditions.
RESUMEN
Monodisperse wurtzite CuIn(x)Ga(1-x)S(2) nanocrystals have been synthesized over the entire composition range using a facile solution-based method. Depending on the chemical composition and synthesis conditions, the morphology of the nanocrystals can be controlled in the form of bullet-like, rod-like, and tadpole-like shapes. The band gap of the nanocrystals increases linearly with increasing Ga concentration, with band gap values for the end members being close to those observed in the bulk. Colloidal suspensions of the nanocrystals are attractive for use as inks for low-cost fabrication of thin film solar cells by spin or spray coating.
RESUMEN
Novel shape- and structural-controlled superparamagnetic nanostructures composed of self-supported spherical and rod-like CoFe(2)O(4) colloidal nanocrystals have been prepared by thermolysis of a stoichiometric Co(2+)Fe(2)(3+)-oleate complex in organic solution with periodic injection of hexane for controlling the nucleation, assembly, and growth of the nuclei.