表面吸附作用调控纳米晶“#21462;向结合”#29983;长动力学及其在尺寸控制中的应用

项目名称： 表面吸附作用调控纳米晶“#21462;向结合”#29983;长动力学及其在尺寸控制中的应用

项目编号： No.20803082

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 张静

作者单位： 中国科学院福建物质结构研究所

项目金额： 20万元

中文摘要： "取向结合"生长机制是纳米尺寸下的独特生长现象，对纳米材料的形貌、尺寸和性质有着重要影响。本项目针对"取向结合"生长动力学的难点，即纳米粒子的生长容易受混合生长机制共同控制，通过引入强表面吸附作用限制了"奥斯特瓦尔德熟化"机制的发生，从而得到单一的"取向结合"生长，以进一步深入研究其生长动力学。通过调节不同强度的表面吸附作用来控制纳米晶的生长机制，获得了较大尺寸范围内的单一"取向结合"生长，并深入探讨了纳米晶的"取向结合"生长动力学；建立了普适性的"取向结合"动力学模型拟合实验结果，理解纳米晶生长过程中的微观动力学问题。在此基础上，运用"取向结合"生长动力学调控纳米材料的尺寸分布和半导体光学性质，为纳米材料的可控合成提供新思路。

中文关键词： 纳米材料生长动力学；表面吸附；"取向结合"机制；尺寸和性质调控

英文摘要： The crystal growth mechanism, kinetics, and microstructure development play a fundamental role in tailoring the materials with controllable sizes and morphologies. The classical crystal growth kinetics - Ostwald ripening (OR) theory is usually used to explain the diffusion-controlled crystal growth process, in which larger particles grow at the expense of smaller particles. In nanoscaled system, another significant mechanism named "oriented attachment (OA)" was found, where nanoparticles with common crystallographic orientation directly combine together to form a larger ones. Comparing with the classical atom/molecular-mediated crystallization pathway, the OA mechanism shows its specific characteristics and roles in the process of nanocrystal growth.However, the inner complicacy of crystal growth and the occurrence of coexisting mechanisms lead to the difficulty and lack of understanding this growth process by the OA mechanism.In this project, strong surface adsorption was introduced as the effective solution to hinder the OR occurring and facilitate the exclusive OA growth stage. By tuning the surface adsorption, we achieved a pure OA growth in a larger size range, so that the microscopic mechanism of OA can be fully investigated. By building a universal OA kinetic models to fit the experimental data and further understanding the growth kinetics of nanoparticles,we created a novel pathway to guide and control the size distribution and shape development of nanostructural materials.

英文关键词： nanocrystal growth kinetics; surface adsorption; oriented attachment mechanism; control of size distribution and properties