Optical Tracking of Multi-walled Carbon Nanotubes by Attaching Functionalized Quantum Dots

Functionalized quantum dots have been successfully attached to multi-walled carbon nanotubes over carbodiimide-assisted coupling. Characterization in a transmission electron microscope shows the quantum dots are attached mainly at the opened tips and defect sites on the side-walls of nanotubes, suggesting the covalent nature of the bonding and high selectivity to chemically reactive sites. Due to their unique fluorescent properties, the visibility of the nanometer-sized quantum dots under an optical microscope creates the possibility of tracking the motion or morphology change of individual decorated nanotubes in a liquid environment and identifying possible sites for covalent attachment. This enables the handling, tracking, and integration of carbon nanotubes with other nanoparticles for building nano/micro engineered and molecular systems