New insights into the photoluminescence of double-walled carbon nanotubes
Résumé
We report the direct and unambiguous evidence of the existence
of inner semiconducting tube (iSCT) photoluminescence (PL)
from measurements performed on four individual free-standing
index-identified double-walled carbon nanotubes (DWNTs).
Based on thorough Rayleigh scattering, Raman scattering and
PL experiments, we are able to demonstrate that the iSCT PL
is observed with a quantum yield estimated as a few 10−6 independently
of the semiconducting or metallic nature of the
outer tube. This result is mainly attributed to ultrafast exciton
transfer from inner to outer tube. Furthermore, by carrying
out PL excitation experiments on the (14,1)@(15,12) DWNT,
we show that the iSCT PL can be detected through the optical
excitation of the outer tube (Fig. 1) indicating that the exciton
transfer can also occur in the opposite way.