Using time-resolved reflectivity measurements on unaligned and aligned bundled single-wall carbon nanotubes with a pump energy of 1.55 eV, quasi-resonant with the second Van Hoye singularity of semiconducting tubes, a positive sign of the transient reflectivity is detected in unaligned nanotubes. In contrast a negative sign is detected in aligned nanotubes. This discovery addresses a long-standing question showing that in unaligned nanotubes the stronger intertube interactions favor the formation of short-lived free charge carriers in semiconducting tubes. A detailed analysis of the transient reflectivity spectral response shows that the free carriers in the photo-excited state of semiconducting tubes move towards metallic tubes in about 400 fs.
Galimberti, G., Pagliara, S., Ponzoni, S., Dal Conte, S., Cilento, F., Ferrini, G., Hofmann, S., Arshad, M., Cepek, C., Parmigiani, F., The photoinduced charge transfer mechanism in aligned and unaligned carbon nanotubes, <<CARBON>>, 2011; 49 (Dicembre): 5246-5252. [doi:10.1016/j.carbon.2011.07.042] [http://hdl.handle.net/10807/10636]
The photoinduced charge transfer mechanism in aligned and unaligned carbon nanotubes
Galimberti, Gianluca;Pagliara, Stefania;Ponzoni, Stefano;Ferrini, Gabriele;
2011
Abstract
Using time-resolved reflectivity measurements on unaligned and aligned bundled single-wall carbon nanotubes with a pump energy of 1.55 eV, quasi-resonant with the second Van Hoye singularity of semiconducting tubes, a positive sign of the transient reflectivity is detected in unaligned nanotubes. In contrast a negative sign is detected in aligned nanotubes. This discovery addresses a long-standing question showing that in unaligned nanotubes the stronger intertube interactions favor the formation of short-lived free charge carriers in semiconducting tubes. A detailed analysis of the transient reflectivity spectral response shows that the free carriers in the photo-excited state of semiconducting tubes move towards metallic tubes in about 400 fs.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.