树枝状与球状PbS纳米结构的组装合成及其形成机理研究

以醋酸铅为铅源,硫代乙酰胺为硫源,在表面活性剂SDS单独作用和表面活性剂SDS和CTAB共同作用下可选择性地组装合成出颗粒以相同晶面粘连组装成的单晶树枝状PbS纳米结构和颗粒以不相同晶面粘连组装成的多晶球状PbS纳米结构,而且提高反应物浓度能起到调节树枝状和球状PbS纳米结构尺寸的作用.对树枝状和球状PbS纳米结构的形成机理进行了初探,发现SDS单独作用时其烷基链起到的软模板作用有利于PbS小颗粒组装成树枝状的PbS纳米结构.当反应溶液中再加入适量的CTAB时,它在溶液中形成微胶束起到了软模板作用,迫使颗粒粘连组装成球状PbS纳米结构,有效地限制树枝状结构的生长.

Assembly Synthesis and Formation Mechanism of Dendritic and Spherical PbS Nanostructures

Single crystal dendritic and polycrystalline spherical PbS nanostructures were synthesized selectively with the assistance of surfactants sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) using Pb(Ac)2 as the plumbum source and TAA as the sulfur source. When the surfactant SDS is used only, the single crystal dendritic PbS nanostructure assembled by nanoparticles through the same crystallographic plane is synthesized. While the surfactants SDS and CTAB are used together, the polycrystalline spherical PbS nanostructure assembled by nanoparticles through the different crystallographic plane is fabricated. It is found that the size of the dendritic and spherical PbS nanostructures can be controlled by the concentration of reactants. Finally, The possible growth mechanism is discussed. It is found that the alkyl chain of SDS may work as a soft template to help the little PbS nanoparticles assemble into dendritic nanostructure while the surfactant SDS is used only. When another surfactant CTAB is added, the formed CTAB micelle in the solution will confine the growth of the dendritic nanostructure and the nanoparticles are obliged to assemble into spherical PbS nanostructure.