Efficient Visible Photoluminescence from Carbon Nanotubes in Zeolite Templates

Abstract

We have found strong visible photoluminescence (PL) from 0.4 nm carbon nanotubes embedded in the ordered channels of a zeolite crystal matrix. The PL exhibits a broad emission band with an efficiency of $\sim 1\%–5\%$. Strong polarization dependence is observed both on the excitation and emission, indicating a preferential optical dipole along the axis of carbon nanotubes. By correlating with the absorption and Raman spectra, we identify $(3,3)$ and $(4,2)$ tubes to be responsible for the PL peaks at $\sim 2.6$ and $\sim 1.7\mathrm{e}\mathrm{V}$, respectively.