多羟基化合物法制备五次孪晶银纳米线的生长机理

运用多羟基化合物方法, 在添加表面活性剂聚乙烯吡咯烷酮(PVP) K30的溶液中合成了多次孪晶银纳米颗粒和纳米线. 运用透射电子显微术(TEM)和光吸收谱, 对不同的摩尔比n(PVP):n(AgNO3)和不同的搅拌条件下制备的纳米线进行了对比研究. 结果表明, 这种方法的制备过程中不仅存在由五个{111}面包裹成的锥形生长, 而且还同时存在垂直于生长方向的{110}层状生长, 并且两者之间还存在着竞争; 另外对纳米线的弯折处进行的高分辨电子显微学研究表明, 纳米线制备过程中遭受的塑性变形在纳米线中产生了大量的层错和位错; 纳米线折断产生的新鲜断口容易成为新的晶粒形核位置.

Growth Mechanism of Penta-twinned Ag Nanowires Synthesized by Polyol Process

Multi-twinned silver nanoparticles and nanowires were synthesized by polyol process in the presence of surfactant poly (vinyl pyrrolidone) (PVP) K30. In order to study the growth mechanism, silver nanowires were synthesized under various conditions by changing n(PVP)/n(AgNO3) and the state of agitation. A comparative study of these nanowires was performed by means of transmission electron microscopy (TEM) and optical absorption spectra. The results showed that there coexisted two different growth modes, and hence the competition between them. According to one mode, the as-synthesized nanowires grew along {111} faces, by which the pentagonal pyramid-shaped tip was enclosed, as the active facets. By another mode, the nanowires grew layer by layer along{110} face, which was perpendicular to the wire axis 110], as the active facet. There weremany stacking faults and dislocations in the nanowires deformed plastically during the preparation of the nanowires. The fresh fracture surfaces of the nanowires were the favorable positions where the nucleation and growth of newly formed crystals might take place.