Super-Stable, Highly Monodisperse Plasmonic Faradaurate-500 Nanocrystals with 500 Gold Atoms: Au-similar to 500(SR)(similar to 120)

作者：Kumara Chanaka; Zuo Xiaobing; Ilavsky Jan; Chapman Karena W; Cullen David A; Dass Amala^*

来源：Journal of the American Chemical Society, 2014, 136(20): 7410-7417.

DOI：10.1021/ja502327a

Determining the composition of plasmonic nanoparticles is challenging due to a lack of tools to accurately quantify the number of atoms within the particle. Mass spectrometry plays a significant role in determining the nanoparticle composition at the atomic level. Significant progress has been made in understanding ultrasmall gold nanoparticles such as Au-25(SR)(18) and Au-38(SR)(24), which have Au core diameters of 0.97 and 1.3 nm, respectively. However, progress in 2-5 nm-diameter small plasmonic nanoparticles is currently impeded, partially because of the challenges in synthesizing monodisperse nanoparticles. Here, we report a plasmonic nanocrystal that is highly monodisperse, with unprecedentedly small size variability. The composition of the superstable plasmonic nanocrystals at 115 kDa was determined as Au500 +/- 10SR120 +/- 3. The Au-similar to 500 system, named Faradaurate-500, is the largest system to be characterized using high resolution electrospray (ESI) mass spectrometry. Atomic pair distribution PDF) data indicate that the local atomic structure is consistent with a face-centered cubic (fcc) or Marks decahedral arrangement. High resolution scanning transmission electron microscopy (STEM) images show that the diameter is 2.4 +/- 0.1 nm. The size and the shape of the molecular envelope measured by small-angle X-ray scattering (SAXS) confirms the STEM and PDF analysis.

• 出版日期2014-5-21