Spectroelectrochemistry of peapods

Spectroelectrochemsitry of peapods

The in-situ spectroelectrochemistry can be also used for the study of more complicated carbon nanostructures like fullerene peapods. The Fig. 1 shows the development of Raman spectra during the charging of C₆₀ fullerene peapods (C₆₀@SWCNT) film deposited on platinum electrode. The spectra are excited by a 488 nm laser line. The main effect of the electrochemical doping is similar to the SWCNT e.g. a subsequent bleaching of all main SWCNT features (RBM, D and TG modes). Therefore electronic structure of the SWCNT is not significantly changed by insertion of C₆₀ into SWCNT.

But the development of C₆₀ modes is different. Cathodic doping of C₆₀@SWCNT causes overall decrease of intensities, while the C₆₀ lines drop below a detectable level. This matches qualitatively the behavior of chemical K-doping. An interesting effect is observed upon progressive anodic doping, which is difficult to be followed chemically.  Fig 1 display a significant increase of Raman intensities of C₆₀ modes. The "anodic enhancement" is apparent for all C₆₀ related modes. As the tube-related modes decline monotonously upon both cathodic and anodic doping (see above), the fullerene-related mode A_g(2) at  around 1470 cm^-1 becomes dominant over the tube-related modes (the D-mode at ca. 1350 cm^-1 and RBM) at positive potentials.

Fig. 1 In situ Raman spectroelectrochemistry of C₆₀@SWCNT

Contact

Prof. Lothar Dunsch