Proton irradiation effect on single-wall carbon nanotubes in a poly(3-octylthiophene) matrix

Proton irradiation effects on interband transitions in single-wall carbon nanotubes matrixed in poly(3-octylthiophene) were investigated. The interband transitions were measured using an optical absorption technique. Two interband transitions were observed, at 0.71 and 1.28 eV in a sample that was subject to 2 MeV proton irradiation to fluences ranging between 5.0 × 10 10 cm − 2 and 5.6 × 10 15 cm − 2 . The optical absorption spectra were collected after cooling the sample to 10 K. The total integrated areas of the two transitions were monitored as a function of proton fluence. The results indicate that proton irradiation to fluences as high as 5.6 × 10 15 cm − 2 has little effect on the interband transitions in carbon nanotubes. However, small radiation-related degradation has been observed as judged by the broadening of the interband transition spectra and by the reduction of the radial breathing mode intensity observed by Raman scattering.