High-Resolution EM of Colloidal Nanocrystal Growth Using Graphene Liquid Cells

1. Jong Min Yuk¹,²,³,*, 
2. Jungwon Park²,⁴,*, 
3. Peter Ercius⁵, 
4. Kwanpyo Kim¹,²,⁶, 
5. Daniel J. Hellebusch⁴,
6. Michael F. Crommie¹,²,⁶, 
7. Jeong Yong Lee³,†, 
8. A. Zettl¹,²,⁶,†, 
9. A. Paul Alivisatos²,⁴,†

Science 6 April 2012: 
Vol. 336 no. 6077 pp. 61-64 
DOI: 10.1126/science.121765

We introduce a new type of liquid cell for in situ transmission electron microscopy (TEM) based on entrapment of a liquid film between layers of graphene. The graphene liquid cell facilitates atomic-level resolution imaging while sustaining the most realistic liquid conditions achievable under electron-beam radiation. We employ this cell to explore the mechanism of colloidal platinum nanocrystal growth. Direct atomic-resolution imaging allows us to visualize critical steps in the process, including site-selective coalescence, structural reshaping after coalescence, and surface faceting.