Scientific Background (Click here for publications using the NanoSpectralyzer)                                                            

Near-infrared band-gap fluorescence from individual semiconducting single-walled carbon nanotubes (SWNT) was discovered in Dr. Weisman's laboratory at Rice University in 2001. Subsequent research deciphered the complex pattern of absorption and emission peaks seen in mixed samples. As a result, each distinct spectroscopic feature has now been assigned to a specific nanotube structure. These structural species differ in diameter and chiral angle, and are uniquely labeled by pairs of integers denoted (n,m).

Interpreted results - Diameter distribution histogram

The near-infrared emission spectra of nanotube samples serve as compositional "fingerprints." One can therefore use spectrofluorimetry to deduce detailed information about the compositions of bulk samples, which invariably contain mixtures of (n,m) species. However, general-purpose spectrofluorometers are not well suited to this task. Although such instruments are versatile, they are also large, slow, and produce raw data that require substantial interpretation to yield the desired analytical result. To provide a more efficient and automated alternative, ANF has developed a specialized fluorimetric instrument designed specifically for SWNT analysis. Our unique fluorimetric analyzer combines a compact, efficient optical system and sophisticated software that acquires and interprets the data. It allows users to easily and rapidly find the identities and amounts of specific (n,m) semiconducting nanotubes in their bulk samples.

Measured fluorescence spectra with fits

Relevant Literature (click on each title for link)

• Band Gap Fluorescence from Individual Single-Walled Carbon Nanotubes, M. O'Connell et al., Science 297, 593 (2002).
• Structure-Assigned Optical Spectra of Single-Walled Carbon Nanotubes, S. M. Bachilo et al., Science 298, 2361 (2002).
  
• Dependence of Optical Transition Energies on Structure for SWCNT in Aqueous Suspension: An Empirical Katuaura Plot,

           R. B. Weisman and S. M. Bachilo, Nano Lett. 3, 1235 (2003).

• Down the Tubes We Glow, D. Bradley, Spectroscopy now (2004).
• Simplifying Carbon Nanotube Identification, R. Bruce Weisman, The Industrial Physicist 24 (2004).
• Carbon Nanotubes, R. B. Weisman and S. Subramoney, The Electrochemical Society's Interface 15, 42 (2006).
• Efficient Fluorimetric Analyzer for SWCNT,ER. B. Weisman et al, WO/2007/001461 (2007).
• Optical Spectroscopy of SWCNT,ER. B. Weisman.