低温固相合成形貌和晶相可控的CdS纳米晶

用表面活性剂为形貌控制剂,通过低温固相反应成功制备出具有不同晶相和形貌的CdS纳米晶.研究结果表明,在反应过程中,表面活性剂所形成的结构对最终纳米晶的形貌起着决定性的作用.若以表面活性剂聚氧乙烯9醚为形貌控制剂,则所制备的产物为立方晶系的β-CdS球形纳米粒子,纳米粒子的直径为5-15 nm;而用聚乙二醇400为形貌控制剂时,则所制备的产物为六方晶系的CdS纳米棒,纳米棒的直径为20-80 nm、长度为100-400 nm.用X射线粉末衍射和透射显微镜技术对所制备纳米晶的成分、晶相、形状和尺寸进行了表征分析.对不同形貌CdS纳米晶的形成机理作了深入的讨论,提出了CdS纳米棒的表面活性剂软模板诱导自组装生长机理.

Shape-and Phase-Controlled Synthesis of CdS Nanocrystals by a Low Temperature Solid-Phase Route

A low temperature solid-phase route has been developed for the synthesis of CdS nanocrystals with different morphology by using surfactant as shape controller. The results indicate that the surfactant plays a key role for controlling the shape of CdS nanocrystals. The cubic phase 13-CdS spherical nanocrystals with diameter of 5 - 15 nm were synthesized when the surfactant nonylphenyl ether was used as shape controller. If the surfactant polyethylene glycol 400 was used as shape controller, the hexagonal phase CdS nanorods （wurtzite structure） with diameter of 20 - 80 nm and length of 100 - 400 nm were successfully fabricated. XRD and TEM techniques were used to study on composition, phase, morphology and size of the as prepared CdS nanocrystals. The growth mechanism of CdS nanocrystals has been discussed in detail. A surfactant soft template induced self-assemble growth mechanism was proposed for the formation of CdS nanorods.