Scientists have learned how to place crystalline
defects in new materials with atomic-scale precision. This enables
materials that can control excitons—energy carriers that are
similar to subatomic particles. New research shows that, by
precisely attaching specific chemical compounds to a carbon
nanotube surface, scientists can create local energy wells that
“capture” the excitons. The wells lower the excitons’ energy state.
This prevents the loss of their energy as heat and controls the
color of the light that they emit.
