Lee Hsun (H.LEE) Young Scientist Lecture Series on Materials Science

Topic: Plumber's Wonderland Found on Graphene

Speaker: Prof. Dr. Ju Li

　　　　　Department of Nuclear Science and Engineering and Department of Materials Science and Engineering

　　　　　Massachusetts Institute of Technology, USA

Time: 15:00-16:30, (Mon.) July 18, 2011

Venue: Room 403, R&D Building, IMR CAS

Welcome to attend !

Abstract

Curvy nanostructures such as carbon nanotubes and fullerenes have extraordinary properties but are difficult to pick up and assemble into devices after synthesis. We have performed experimental and modeling research into how to integrate curvy nanostructures on flat graphene, taking advantage of the fact that graphene bends easily after open edges have been cut on it, which can then fuse with other open edges, like a plumber connecting metal fittings. By applying electrical current heating to few-layer graphene inside an electron microscope, we observed the in situ creation of many interconnected, curved carbon nanostructures[1], such as graphene bilayer edges (BLEs) aka “half nanotubes”, BLE polygons, and nanotube-BLE junctions connecting multiple layers of graphene. A novel piezoelectric effect causes the BLEs to have large permanent electric dipoles of 0.87 and 1.14 Debye/Å for zigzag and armchair inclinations, respectively[2]. Unlike carbon nanotubes which fold graphene by 2π rotation and are highly poly-disperse in chiralities and radius, BLEs are highly mono-disperse structures due to the p rotation and a lattice orientation constraint during processing[4]. Further investigations indicate that multiple-layer graphene offers unique opportunities for tailoring carbon-based structures and engineering novel nano-devices with complex topologies[1-5].