Anal Chem. 2011 Nov 1;83(21):8069-72. doi: 10.1021/ac202520p. Epub 2011 Oct 11.
Preparation of clean monodisperse samples of clusters and nanoparticles for characterization using cutting-edge analytical techniques is essential to understanding their size-dependent properties. Herein, we report a general method for the preparation of high surface coverage samples of monodisperse clusters containing an exact number of atoms. Polydisperse solutions of diphosphine-capped gold clusters were produced by reduction synthesis. Electrospray ionization was used to introduce the clusters into the gas phase where they were filtered by mass-to-charge ratio allowing clusters of a selected size to be deposited onto carbon coated copper grids at well controlled kinetic energies. Scanning transmission electron microscopy (STEM) analysis of the soft landed clusters confirms their monodispersity and high coverage on the substrate. The soft landing approach may be extended to other materials compatible with an array of available ionization techniques and, therefore, has widespread utility as a means for controlled preparation of monodisperse samples of nanoparticles and clusters for analysis by transmission electron microscopy (TEM).
为了使用前沿分析技术对团簇和纳米粒子进行特征分析，制备清洁的单分散样品至关重要，这有助于理解它们的尺寸相关性质。在此，我们报告了一种通用的方法，用于制备具有精确原子数的单分散团簇的高表面覆盖率样品。通过还原合成制备了双膦配体封端的金团簇的多分散溶液。采用电喷雾电离将团簇引入气相中，然后通过质荷比进行过滤，使选定尺寸的团簇沉积在控制动力学能量的碳涂覆的铜网格上。软着陆团簇的扫描透射电子显微镜（STEM）分析证实了它们的单分散性和在基底上的高覆盖率。软着陆方法可以扩展到与一系列可用的离子化技术兼容的其他材料，因此作为一种通过透射电子显微镜（TEM）分析来控制制备单分散纳米粒子和团簇样品的方法具有广泛的用途。
