Femtosecond transient absorption spectroscopy of single-walled carbon nanotubes in aqueous surfactant suspensions: Determination of the lifetime of the lowest excited state

• Published in: Physical chemistry chemical physics : PCCP 2005-02, Vol.7 (3), p.512-517
• Main Authors: YANG, J.-P, KAPPES, M. M, HIPPLER, H, UNTERREINER, A.-N
• Format: Article
• Language: English
• Subjects: Carbon; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Kinetics; Nanotubes; Nanotubes, Carbon; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Spectrophotometry, Infrared - methods; Spectrum Analysis - methods; Water - chemistry
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/b415524f

Femtosecond one- and two-colour pump-probe spectroscopy of single-walled carbon nanotubes (SWNTs) individual in aqueous surfactant suspensions has been used to assess the "intrinsic" lifetime of the lowest excited states. We demonstrate that such measurements can be perturbed by several competing photophysical processes thus making lifetime deconvolution difficult. Furthermore we show how these effects, arising primarily from sample heterogeneity, can be reduced. Measurements of induced transients in the near IR yield lifetimes of (35 +/- 10) ps and (56 +/- 10) ps, for nanotubes having mean diameters of 0.95 and 1.2 nm, respectively. Furthermore, a fast decay component in the ps to sub-ps regime is also observed. We tentatively attribute this to relaxation in SWNT bundle components.