球状、立方状及空心立方状PbS纳米晶的控制合成及其形成机理

以醋酸铅为铅源，硫代乙酰胺为硫源，在表面活性剂十二烷基硫酸钠(SDS)和十六烷基三甲基溴化铵(CTAB)共同作用下，通过简单地调节水热反应的反应温度控制合成出球状、立方状和空心立方状PbS纳米晶。利用XRD、TEM对合成产物的结构和形貌进行了表征，发现合成的球状、立方状和空心立方状PbS纳米晶尺寸均一，直径为100 nm左右。对球状、立方状和空心立方状PbS纳米晶的形成机理进行了初探，结果表明反应温度较低时，水热反应初始阶段形成的PbS小颗粒呈球形，在表面活性剂SDS的烷基链模板和CTAB微胶束软模板共同作用下生成球状PbS纳米晶；反应温度较高时，水热反应初始阶段形成的PbS小颗粒由于自身的立方相岩盐晶体结构的影响有呈立方状趋势，在SDS和CTAB共同作用下产物堆积成空心立方体状或立方状。

Controllable Synthesis and Formation Mechanism of Spherical, Cubic and Hollow Cubic PbS Nanocrystals

Spherical, cubic and hollow cubic PbS nanocrystals were synthesized by controlling the reaction temperature of the hydrothermal reaction of Pb(Ac)₂, thioacetamide(TAA), sodium dodecyl sulfate(SDS), and Cetyltrimethylammonium bromide(CTAB). The microstructure and morphology of the products were characterized by XRD and TEM. The results show that the synthesized spherical, cubic and hollow cubic PbS nanocrystals are monodispersed and the diameter of those nanocrystals is about 100 nm. Finally, the possible growth mechanism was discussed. When the reaction temperature is lower, the smaller PbS nanoparticles will assume spherical shape formed in the initial reaction. The spherical PbS nanocrystals were synthesized by assembly of those smaller nanoparticles with the help of the alkyl chain in SDS and micro-micelle of CTAB. When the reaction temperature is raised, the smaller PbS nanoparticles have the trend to assume cubic shape formed in the initial reaction for their cubic rock-salt crystal structure. Therefore, the obtained products would be hollow cubic or cubic PbS nanocrystals assembled by those smaller cubic PbS nanoparticles.