基于光吸收特性探究面心立方结构Au纳米团簇向纳米晶转变的“拐点”

Au纳米团簇是连接Au原子分子与Au纳米晶的桥梁，其尺寸通常小于3 nm，具有特殊的量子限域效应。虽然国内外多个课题研究了不同尺寸和结构的Au纳米团簇，但是对Au纳米团簇向纳米晶转变的“拐点”了解甚少，存在数个悬而未决的问题。比如，用何种技术手段寻找Au纳米团簇向纳米晶转变的“拐点”？Au纳米团簇向纳米晶转变过程的光学性质如何变化？为了解决这些问题，本项目拟开展三个方面的工作：（1）利用尺寸融合、酸诱导以及离子诱导等方法合成出具有面心立方结构但是尺寸不同的Au纳米团簇；（2）利用紫外可见吸收光谱技术研究Au纳米团簇短波吸收峰波长与尺寸的关系，以Au纳米晶的表面等离子体吸收峰（520 nm）为基准寻找Au纳米团簇向纳米晶转变的“拐点”；（3）在Au纳米团簇向纳米晶转变的“拐点”附近研究Au纳米团簇的荧光和拉曼性质的变化规律。本项研究不仅对基础研究有促进作用且具备一定的应用价值。

As a bridge connecting Au atoms and Au nanocrystals, Au nanoclusters are usually smaller than 3 nm in size and have a special quantum confinement effect. Although many groups have studied Au nanoclusters with different sizes and structures, the "inflection point" of properties transition from Au nanoclusters to nanocrystals is still little known. For example, what technical characterization means can be used to identify the "inflection point"? How does the optical properties change during the transition from Au nanoclusters to nanocrystals? In order to answer these questions, three tasks in this project will be carried out: (1) Using various methods, such as size focusing, acid induction and ion induction, to prepare face-centric cubic Au nanoclusters with different sizes; (2) Employing the ultraviolet visible absorption spectroscopy to study the relationship between the size of Au nanocluster and the wavelength of short-wave absorption peak, aiming to find the "inflection point" on the basis of the surface plasma absorption peak (520 nm) of Au nanocrystals; (3) Studying the fluorescence and Raman properties of Au nanoclusters near the "inflection point" and simultaneously revealing the properties change from nanoclusters to nanocrystals. The completion of the above work not only promotes the basic research but also has practical application value.