Introduction
Single-walled carbon nanotubes (SWCNTs) can be viewed as rolled-up sheets of graphene, where the precise roll-up angle and diameter determine the optical and electronic properties of the resulting quasi-1D (semi)conductor. Advanced nanotube growth methods and modern dispersion and sorting techniques provide access to large amounts of purely semiconducting and even single-chirality SWCNTs with specific diameters and bandgaps that can be integrated into (opto-)electronic devices and optical sensors with outstanding performance. In addition to high charge carrier mobilities, SWCNTs show diameter-dependent photoluminescence (PL) with narrow linewidth in the second biological and telecommunication windows (1000–1600 nm). The covalent functionalization of SWCNTs with luminescent quantum defects leads to even further red-shifted emission and higher PL quantum yields. These luminescent defects transform sorted and functionalized SWCNTs into a very promising material for next-generation in-vivo imaging, optical metabolite sensing, and single-photon emission.
I will introduce the unique optical properties of semiconducting SWCNTs and quantum defects, then explore the chemical strategies for creating and tuning luminescent defects for optical sensing of biomolecules and super-resolution bioimaging.