One Pot Solvothermal Synthesis Of Metal Calcogenide Semiconductor Nanocrystals By Using Metal Acetylacetonate And Dodecanethiol As Reactants

Nanocrystalline materials have attracted a great deal of attention from researchers in various areas forboth their fundamental size-and shape-dependent properties and their many important technologicalapplications. During the last few years, researchers have been extensively studying efficient syntheticroutes to well-defined nanocrystals with controlled size and shape. The typical synthesis methods aregas-phase syntheses utilizing vapor–liquid–solid （VLS） methods, chemical vapor deposition （CVD）,thermal evaporation, and liquid-phase colloidal syntheses in aqueous or non-aqueous media. Theliquid-phase colloidal synthetic approach is an especially powerful tool for the convenient and reproducibleshape-controlled synthesis of nanocrystals not only because this method allows for the resultingnanocrystals to be precisely tuned in terms of their size, shape, and composition on the nanometer scale butalso because it allows them to be dispersed in either an aqueous or a nonhydrolytic media. Moreover, thesecolloidal nanocrystals are often referred to as “molecular nanocrystals” and can be modified by chemicalhybridization with other functional materials for applicationsin electronics and biological systems. Here,the nonhydrolytic high-temperature thermal reaction method was used to obtain the colloidal metalcalcogenide semiconductor nanocrystals. This thesis includes the following main aspects:1. In chapter2, monodisperse Cu₂S nanocrystals were synthesized by one-pot reaction between cupricdiacetylacetonate（Cu（acac）₂） and dodecanethiol （DDT） in1-octadecene （ODE）. We could adjust the size ofthe synthesized namocrystals （size from4nm to17nm） by adjust the concentration of DDT, when DDTwas set at lower concentration, the average diameter of as-synthesized Cu₂S nanocrystals was increased asthe increasing amount of DDT, while it was decreased when the amount of DDT was set at a relativelyhigher concentration. Furthermore, the obtained Cu₂S nanocrystals could easily assemble intotwo-dimensional and three-dimensional superlattice structures.2. In chapter3, SnS nanosheets were synthesized by one-pot reaction between cupricBis（acetylacetonato）dichlorotin（Sn（acac）₂Cl₂） and dodecanethiol （DDT） in1-octadecene （ODE）.Transmission electron microscopy （TEM）, high resolution transmission electron microscopy （HRTEM）,X-ray diffraction （XRD）, and selected area electron diffraction （SAED） were used to confirmthemorphology and crystal structure of as-obtained SnS nanosheets.The influences of variable reaction parameters such as types of surfactant, monomer concentration, temperature, etc on the size and shape ofthe synthesized nanocrystals are still obscure.