摘要
CdS半导体纳米簇具有独特的光、电性能,如何制备均匀分散的、能够稳定存在的CdS纳米簇是目前的研究热点之一.以聚酰胺-胺(PAMAM)树形分子为模板,原位合成了CdS纳米簇.首先用UV-Vis分光光度法研究了与树形分子的配位机理,得出G4.5和G5.0的平均饱和配位数分别为16和34,并发现在G4.5PAMAM树形分子中Cd2+主要与最外层叔胺基配位,在G5.0PAMAM树形分子中Cd2+主要与最外层伯胺基配位.酯端基的G4.5的模板作用要明显优于胺端基的G5.0.通过改变Cd2+与G4.5树形分子的摩尔比可以得到不同粒径的CdS纳米簇.溶液的pH值对CdS纳米簇影响很大,pH在7.0左右制备的CdS纳米簇粒径小而均匀,且溶液稳定性高.用UV-Vis分光光度计和TEM对CdS纳米簇的大小和形貌进行了表征.结果表明TEM观测CdS纳米簇的粒径要大于用Brus公式的估算值.
The complexation between PAMAM dendrimers and Cd2+ was studied by titrating PAMAM dendrimers with dilute cadmium acetate methanol solution under the monitoring of UV-Vis spectrophotometry. The results showed that the average number of Cd2+ complexed with a PAMAM dendrimer is 34 for a primary amine-terminated G5.0 dendrimer and 16 for an ester-terminated G4.5 dendrimer. A series of CdS/PAMAM dendrimer nanocomposites of different diameters were prepared by leading H2S into the methanol solution of Cd2+/PAMAM complexes with different Cd2+/PAMAM ratio. The gained CdS/ PAMAM dendrimer nanocomposites were characterized by UV-Vis spectrophotometry and TEM. The study implied that G4.5 PAMAM dendrimers were better templates. The stability, diameter and dispersion of the US clusters were affected remarkably by the changes of the ratio of Cd2+ to G4.5 PAMAM dendrimer and pH of the solution. The results showed that in neutral solution the stability and the dispersion of CdS/PAMAM dendrimer nanocomposites were better and the diameters were smaller.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2005年第5期421-426,共6页
Acta Chimica Sinica
基金
教育部跨世纪优秀人才培养计划基金资助项目.
