From CdTe Nanoparticles Precoated on Silicon Substrate to Long Nanowires and Nanoribbons: Oriented Attachment Controlled Growth

This manuscript describes a simple, environmentally friendly strategy for the rapid and large-scale growth of ultralong nanowires and nanoribbons of wurtzite CdTe. The nanowires and nanoribbons were prepared through the direct hydrothermal treatment of CdTe nanoparticles precoated on ⟨100⟩ Czochralski silicon, which did not involve complicated reactions. The well-crystalline nanowires and nanoribbons were grown along the [102] direction and were up to 100 μm long. The growth of the nanowires and nanoribbons was dominated by the mechanism of oriented attachment, which was clarified through the tracing of the temporal evolution of CdTe nanoparticles coated on the silicon substrate in the process of hydrothermal treatment. Furthermore, the proposed strategy was also effective in the preparation of anisotropic nanostructures of other II−IV group compounds (e.g., ZnO and CdSe)

Solution-Based Doping of Manganese into Colloidal ZnO Nanorods

This manuscript describes the low-temperature, solution-based doping of Mn2+ ions into colloidal ZnO nanorods, and the yield of the products is in a gram scale. The structures and chemical compositions of the products were characterized by XRD, XPS, EDS, and FT-IR spectroscopy. The results demonstrate that Mn2+ ions were successfully incorporated into the lattice position of Zn2+ ions in ZnO. The concentration of Mn2+ ions (in molar %) in the products can be controlled in the range of 1.25∼5%. The surfaces of Mn-doped ZnO nanocrystals have very rich hydroxyl groups, which enhance their solubility in many polar and nonpolar solvents. TEM and FESEM were used to characterize the morphology of ZnO and Mn-doped ZnO nanocrystals, and they revealed that both the undoped and doped ZnO nanocrystals are composed of uniform nanorods with a diameter of 8 nm and a length of 95 nm. The doping of Mn2+ ions has significant influences on the optical properties of ZnO nanorods. UV−vis absorption spectroscopy measurements reveal that the doping of Mn2+ lead to a red shift of the absorption edge of ZnO nanorods. Undoped ZnO nanorods exhibit a pure excitonic emission centered at 384 nm, whereas Mn-doped ZnO nanorods only show a red emission that is assigned to the Mn2+ 4T(G) ligand-field excited state

Preparation and Characterization of Bifunctional ZnO/ZnS Nanoribbons Decorated by γ-Fe₂O₃ Clusters

This manuscript presents the preparation and characterization of polycrystalline ZnO/ZnS nanoribbons decorated by γ-Fe2O3 clusters. The weight percentages of ZnO, ZnS, and γ-Fe2O3 in the product were 22.2, 69.3, and 8.5%, respectively. The nanoribbons were synthesized by a two-step, solution-based method. First, porous ZnO/ZnS microspheres were solvothermally prepared. Then, Fe2+and Fe3+ ions were transferred into the microspheres due to their porous property and good adsorption ability. Finally, a mineralizer such as ethylenediamine or aqueous ammonia or urea was introduced into the system to promote the mineralization of Fe2+and Fe3+ ions as well as the transformation of microspheres into nanoribbons. Through tracing the morphology evolution of porous microspheres to nanoribbons by transmission electron microscopy, the growth of the nanoribbons is clarified to be dominated by a dissolution−reconstruction mechanism. The measurements of the optical and magnetic properties revealed that these nanoribbons are bifunctional and have integrated the photoluminescent effect of ZnO and ZnS and the ferromagnetism of γ-Fe2O3