Photoluminescence quenching in peapod-derived double-walled carbon nanotubes

Photoluminescence (PL) behavior of peapod-derived double-walled carbon nanotubes (DWNTs)—the simplest form among multiwalled carbon nanotubes—is investigated. Even though the optical absorption and the resonant Raman spectra show the characteristic features of DWNTs, the PL signals originated from DWNTs are severely suppressed. This suppression is a consequence of an interlayer interaction between the inner and the outer tubes that efficiently quenches the PL signals of the DWNTs.

Figure 1

(Color) HRTEM images of DWNT SDBS ${\mathrm{D}}_2\mathrm{O}$. Scale $\text{bar}=10\mathrm{nm}$.

Figure 2

(a) UV-vis-NIR absorption spectra of DWNT-SDBS-${\mathrm{D}}_2\mathrm{O}$ and SWNT-SDBS-${\mathrm{D}}_2\mathrm{O}$ solutions. (b) Low-resolution resonant Raman spectra of a DWNT-SDBS-${\mathrm{D}}_2\mathrm{O}$ solution excited at 975, 1038, and $1064\mathrm{nm}$. (c) High-resolution resonant Raman spectrum of a DWNT-SDBS-${\mathrm{D}}_2\mathrm{O}$ solution excited at $1064\mathrm{nm}$. (d) An expanded view of the high-resolution Raman spectrum of the inner tubes.

Figure 3

(Color) Two-dimensional (2D) photoluminescence contour map of a DWNT-SDBS-${\mathrm{D}}_2\mathrm{O}$ solution.

Figure 4

(Color) 2D PL contour maps of (a) DWNT-SDBS-${\mathrm{D}}_2\mathrm{O}$ and (b) SWNT-SDBS-${\mathrm{D}}_2\mathrm{O}$ solutions in the longer wavelength region. (c) PL intensity ratio between DWNTs and SWNTs $(I^{\mathrm{DW}}∕I^{\mathrm{SW}})$ as a function of a tube diameter, where each PL intensity ratio was normalized to that of a (15,1) tube.