The Importance of Defects in Controlling the Chemistry of Single-Walled Carbon Nanotubes

Defects in single-walled carbon nanotubes (SWCNTs) serve as active sites for chemical reactions, enabling selective functionalization and molecular interactions that are otherwise inaccessible in pristine SWCNTs. By altering the electronic structure and local reactivity, defects play a pivotal role in controlling the chemistry of SWCNTs, dictating how they interact with external molecules. In this mini-review, we explore how defect engineering transforms SWCNTs into platforms for chemical transformations, starting with the photophysical principles governing defect-induced optical transitions. We then examine strategies for introducing atomic and molecular defects, their influence on fluorescence behavior, and their role in facilitating chemical reactions. Additionally, we discuss the challenges in establishing direct correlations between defect composition and both optical and chemical properties. Finally, we highlight emerging opportunities for defect-engineered SWCNTs in molecular sensing, bioimaging, and catalysis, emphasizing the need for rational chemical design strategies to harness their full potential.