Houston, TX 77005
4:00 p.m. Wednesday, March 27, 2013
On Campus | Alumni
ABSTRACT: Defects can rule the properties of a crystal. This effect is particularly intriguing in atom-thick materials such as single-walled carbon nanotubes and graphene, where new chemical and physical phenomena may arise due to strong coupling of electrons, excitons, phonons, and spins with defects in reduced dimensions. In this talk, I will discuss chemical strategies developed in my lab to address the challenge of understanding and controlling covalent functional defects on sp2 carbon lattices. Covalent chemical reactions typically occur randomly on sp2 carbon lattices because electrons are delocalized. The modifications rapidly destroy the electrical and optical properties that make carbon-based materials desirable for many energy and electronic applications. We found that Billups-Birch alkylcarboxylation, a variant of the nearly century-old Birch reduction, occurs on sp2 carbon lattices nearly exclusively by defect activated propagation. This unexpected mechanism allows, for the first time, growth of “functional bands” on sp2 carbon lattices in a way reminiscent of crystal growth from a “seed”. Implications of these findings to the applications of carbon nanomaterials (e.g., in creating a beaded-string silicon anode and chemical sensors) also will be discussed.