Solution-phase Controlled Synthesis And Formation Mechanism Of One-dimensional Nanostructured Materials

The aim of this dissertation is to explore the synthesis of one-dimensional nanomaterials by solution-phase route. The as-prepared nanomaterials are characterized in detail and their formation mechanism is also briefly discussed. The main contents can be summarized as follows:1. We developed surfactant-assisted hydrothermal route to prepare inorganiccompounds nanobelts. Single-crystalline SnS₂ nanobelts were hydrothermallysynthesized on a large scale at 180℃for 24h, using NH₃·H₂O, CS₂, andSnCl₄·5H₂O as reagents at the assistance of dodecanethiol. In this hydrothermalsystem, dodecanethiol plays key roles in formation process of SnS₂ nanobelts. Itcan cover the surface of the incipient SnS₂ crystal nucleus and prevent them fromdissolving by superfluous S^2- ions. It limits the concentration of free Sn⁴⁺ ions insolution by coordinating with Sn⁴⁺ ions and thus controls the nucleation rate ofSnS₂. It can selectively adsorb on some crystallographic facets of SnS₂ and resultin the preferential growth of the other crystal facets, which eventually makes SnS₂crystal nucleus grow into nanobelts. By dodecylamine-assisted hydrothermal route,PbI₂ nanobelt bundles were first synthesized. By simple sonication, individualsingle-crystalline nanobelt could be obtained. One side dodecylamine as Bronstedalkali can control the nucleation rate of PbI₂ On the other hand, it can act as softtemplate to direct the formation of PbI₂ nanobelt bundles. Both the results ofresearch of SnS₂ nanobelts and PbI₂ nanobelt bundles were published in Journal ofNanoscience and Nanotechnology.2. One-dimensional leaf-shaped SnS₂ nanocrystals were obtained by a direct hydrothermal pyrolysis of single molecular precursor Sn(CH₃CH₂OCS₂)₄. Based on TEM observation of products at the different reaction period of time, the formation of leaf-shaped SnS₂ nanocrystals was suggested via producing lamellae-breaking into nanosheets-assembling and rolling process. This study is under review.3. A novel complex-assisted hydrothermal route is presented to prepare ultralongAg/C nanocables. By chemically etching as-prepared Ag/C nanocables,high-quality carbonaceous nanotubes can be first obtained at room temperature. Anew strategy for introducing guest materials into nanotubes is presented: usingas-prepared Ag/C nanocables as templates, guest materials can be introduced intocarbonaceous nanotubes by chemical reaction with Ag cores. An example forintroducing Ag₂S into carbonaceous nanotubes was taken and this kind ofencapsulation structures was also characterized in detail. These results werepublished in Inorganic Chemistry.4. Nanoparticles-assembled Ag₂S nanorods and nanotubes were synthesized via asurfactant-assisted solvothermal route. The formation of Ag₂S includes twostages: within initial several hours, the product is AgSCN, which subsequentlyslowly transforms into Ag₂S. Potassium oleate plays two kinds of roles. On oneside, it works as soft template to control the morphologies of the initial AgSCN.On the other hand, it acts as bonding agent to fabricate Ag₂S nanorods andnanotubes. PL spectrum of as-prepared Ag₂S nanotubes exhibits two emissionpeaks at room temperature. Its luminescence probably correlates to defectstructure resulting from the assembly of tiny nanoparticles. This study waspublished in Journal of Crystal Growth.5. Organometallic tris(8-hydroxyquinoline)aluminum nanorod bundles were prepared by a surfactant-assisted hydrothermal route. Dodecyl benzenesulfonate can combine with Al³⁺ ions and limit the nucleation and growth rate of tris(8-hydroxyquinoline)aluminum, and act as soft template. Compared with the PL spectrum of amorphous nanoparticles reported, as-prepared tris(8-hydroxyquinoline)aluminum nanorod bundles show obvious blue shift. Its PL emission was evidently enhanced than submicron particles prepared by the same hydrothermal method. This study was published in Chemistry Letters.