| In the past few years, nanomaterials with defined dimensions and shapes haveattracted much attention because of their great potential in various areas, such as light-emitting diodes (LEDs), solar cells, catalysis, biolabeling, and so on. Among thesenanomaterials, semiconductor-based one-dimensional (1D) building blocks (such as nanorodsand nanowires) have attracted intense research interests due to their tunable aspect ratio andcarrier confinement effect, which may result in novel optoelectronic properties andcontributes potentially to a wide range of applications. To date, both gas phase and solutionphase methods have been adopted for the controlled synthesis of1D nanomaterials. Meantime,the future of1D nanoscale building blocks will be largely dependent on how well we canbalance the issues of cost, performance, and stability of such building block-based devicesand systems. Therefore, it is still very important to exploit new synthesis methods since theefficient and controllable synthesis of highly crystallized1D nanoscale building blocks is stilla challenge topic.This thesis includes the following main aspects:In chapter2, high-quality, monodisperse, and size-controlled Ag-ZnS nanorods ornanowires have been synthesized successfully by using Ag nanocrystals as seeds. Such one-dimensional colloidal Ag-ZnS nanorods or nanowires having purposefully controlleddiameter in the range of5-9nm and the length of18-600nm were obtained by altering thereaction conditions, such as concentration, reaction time, reaction temperature, and diameterof Ag nanocrystals. The conjunction interface of Ag-ZnS nanorods or nanowires consists of the (200) plane of Ag nanocrystal and (101) plane of ZnS rod or wire, the （101） directionsof ZnS nanorods grow preferentially. Based on the photoluminescence and lifetime of Ag-ZnS nanorods, it was found that Ag nanocrystals enhanced radiative rate eventually, thefluorescence intensity of Ag-ZnS nanorods can be tuned by changing the size of the Ag seeds.The Ag-ZnS nanorods or nanowires showed greatly improved optical properties compare withZnS nanocrystals, the maximum emission was around402nm and photoluminescencequantum yield was up to30%when5nm Ag nanocrystals were used as seeds.In chapter3, A Facile Route to Pb(OH)Cl nanowires by solution-liquid-solidmethod. We use acetylacetonate lead and lead chloride as raw materials, and then select theoleic acid, oleylamine mixed surfactant successfully prepare the high-quality Pb(OH)Clnanowires. The as-prepared Pb(OH)Cl nanowires were nearly defect-free with uniformdiameter along the entire length. The wires,dimensions could be tuned from80to160nm indiameter, and lengths up to hundreds of micrometers were obtained by tailoring reactionconditions, some of the nanowires align into bundles with individual nanobelts being greaterthan50μm long. Transmission electron microscopy (TEM), high resolution transmissionelectron microscopy (HRTEM), X-ray diffraction (XRD), and selected area electrondiffraction (SAED) were used to confirmthe morphology and crystal structure of as-obtainedPb(OH)Cl nanowires. The HRTEM image indicates that the nanowires are growing along the（111） direction. X-ray diffraction (XRD) pattern from the as-prepared nanowires revealsthe orthorhombic crystal structure, which is consistent with the HRTEM results. High-qualityand monodisperse lead chalcogenides PbE (E=S, Se, Te) nanocrystals. have beensynthesized successfully by using Pb(OH)Cl nanowires as precursors. |
PDF Full Text Request