MIT

Researchers at MIT have produced a catalog of the exact sizes and shapes of defects and holes that would most likely be observed (as opposed to the many more that are theoretically possible) when a given number of atoms is removed from the atomic lattice. The MIT team collaborated on this project with researchers at Lockheed Martin Space and Oxford University.

The 12 different forms that six-atom vacancy defects in graphene can have, as determined by the researchers

“It’s been a longstanding problem in the graphene field, what we call the isomer cataloging problem for nanopores,” Michael Strano from MIT says. "For those who want to use graphene or similar two-dimensional, sheet-like materials for applications including chemical separation or filtration", he says, “we just need to understand the kinds of atomic defects that can occur,” compared to the vastly larger number that are never seen".

An international research team, co-led by researchers at the University of California, Riverside, which also included researchers at MIT, Nanyang Technological University, Singapore; Institute of High Performance Computing, Singapore; UC Berkeley; and National Institute for Materials Science, Japan, has found a new mechanism for highly-efficient charge and energy flow in graphene, opening the door to new types of light-harvesting devices.

The researchers made pristine graphene into different geometric shapes, connecting narrow ribbons and crosses to wide open rectangular regions. They found that when light illuminated constricted areas, such as the region where a narrow ribbon connected two wide regions, a large light-induced current, or photocurrent, was detected.