Controlled Introduction of sp³ Quantum Defects in Fluorescent Carbon Nanotubes by Mechanochemistry

Precise control over low-dimensional materials holds an immense potential for their applications in sensing, imaging and information processing. The controlled introduction of sp³ quantum defects (color centers) can be used to tailor the optoelectronic properties of single-walled carbon nanotubes (SWCNTs) in the tissue transparency (>800 nm) and the telecommunication window. However, an uncontrolled functionalization of SWCNTs with defects leads to a loss of the NIR fluorescence. Here, we use mechanochemistry with aryldiazonium salts to create quantum defects in SWCNTs. The reaction proceeds within 5 min without solvents or illumination and can be controlled by a varied mechanochemical energy impact. By working in the solid-state, this method presents an alternative synthetic route and marks a crucial step for tailoring photophysics of SWCNTs.