Graphene Lends Microscopy Support

Graphene’s single-carbon-atom thickness, exceptional mechanical strength, and electrical conductivity are driving researchers to develop all sorts of nanoelectronic devices, supercapacitors, and polymer-based composites. Zonghoon Lee, Ki-Joon Jeon, and coworkers of the University of California, Berkeley, and Lawrence Berkeley National Laboratory have now demonstrated graphene’s utility in an altogether different application: as a specimen support in transmission electron microscopy (Nano Lett., DOI: 10.1021/nl901664k). Conventional TEM carbon supports are 2 to 3 nm thick and contribute to overall electron scattering during imaging, which diminishes image contrast for low-atomic-number materials. That condition limits the level of detail at which organic layers on metal particles and the interfaces between those materials can be studied. The Berkeley team therefore prepared gold nanoparticles capped with a few molecular layers of a citrate compound and laid the particles on top of a sheet of graphene. In contrast to conventionally supported specimens, the organic layers and interfaces of the graphene-supported samples can be imaged with atomic resolution.