Stepwise Quenching of Exciton Fluorescence in Carbon Nanotubes by Single-Molecule Reactions

• Published in: Science (American Association for the Advancement of Science) Vol. 316; no. 5830; pp. 1465 - 1468
• Main Authors: Cognet, Laurent, Tsyboulski, Dmitri A, Rocha, John-David R, Doyle, Condell D, Tour, James M, Weisman, R. Bruce
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 08.06.2007; The American Association for the Advancement of Science; American Association for the Advancement of Science (AAAS)
• Subjects: Carbon; Carbon nanotubes; Chemical bases; Chemical reactions; Chemiluminescence; Chemistry; Condensed Matter; Diazonium Compounds - chemistry; Emission; Emission spectra; Exact sciences and technology; Excitation; Excitons; Fluorescence; Gels; General and physical chemistry; Hydrogen-Ion Concentration; Luminescence; Microscopy; Microscopy - methods; Nanotubes; Nanotubes, Carbon - chemistry; Optics; Other; Perturbation methods; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Physics; Quenching; Reactants; Segments; Exciton; Singlewalled nanotube; Acids; Luminescence quenching; Photoluminescence; Fluorescence; Carbon nanotubes; Diazonium compounds; Base; Monomolecular reaction; carbon nanotube; luminescence; exciton; SWNT; Single molecule
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1141316

Single-molecule chemical reactions with individual single-walled carbon nanotubes were observed through near-infrared photoluminescence microscopy. The emission intensity within distinct submicrometer segments of single nanotubes changed in discrete steps after exposure to acid, base, or diazonium reactants. The steps were uncorrelated in space and time and reflected the quenching of mobile excitons at localized sites of reversible or irreversible chemical attack. Analysis of step amplitudes revealed an exciton diffusional range of about 90 nanometers, independent of nanotube structure. Each exciton visited about 10,000 atomic sites during its lifetime, providing highly efficient sensing of local chemical and physical perturbations.