  Photoluminescence properties of semiconducting single wall carbon nanotubes
(s-SWNT) thin films with different metallic single wall carbon nanotubes
(m-SWNT) concentrations are reported. s-SWNT purified samples are obtained by
polymer assisted selective extraction. We show that a few m-SWNT in the sample
generates a drastic quenching of the emission. Therefore, highly purified
s-SWNT films are a strongly luminescent material and a good candidate for
future applications in photonics, such as near infrared emitters, modulators
and detectors.
