Photoconductivity and optical properties in composites of poly(paraphenylene vinylene) and single-walled carbon nanotubes

Composites Based on Conducting Polymers and Carbon Nanotubes

“…The evolution of these bands confirms the aggregation of SWNTs by an increase in their concentration. The whole spectra of PPV/SWNT composites recorded at l exc ¼ 676.4 nm ( Figure 5.17) show also that, even at high concentration of SWNTs (64%) the asymmetric G -band is still present [207]. This is proof that SWNTs have been neither covalently bonded to nor doped with the PPV polymer.…”

“…This is a consequence of a structured wrapping of the polymer onto the nanotube lattice, and a signature of strong noncovalent binding [204,205]. Another method of preparation of composites based on SWNTs and PPV was reported by S. Lefrant's group [206,207]. The materials were prepared by mixing SWNTs at different weight concentrations in the soluble sulfonium polyelectrolyte precursor of PPV, with sonication.…”

“…In addition, photoluminescence spectra were strongly modified, in both intensity and shape, with the appearance of new bands in the blue range. This was interpreted as the formation of short conjugated segments that dominate long segments in composite materials [206,207].…”

“…An example is the case of SWNTs noncovalently functionalized with PPV. Thus, in Figure 5.16, Raman spectra recorded in the low-frequency range where RBM of nanotubes are observed reveal specific features at l exc ¼ 1064 nm [207]. Two components are present at 160 and 180 cm À1 , assigned to tubes in isolated and in bundled forms, respectively [113].…”

Enhanced luminance of MEH-PPV based PLEDs using single walled carbon nanotube composite as an electron transporting layer

“…Thus devices based on Alq 3 as ETL are not commercially viable. Incorporation of single walled carbon nanotubes (SWCNTs) in the conducting medium has been suggested by many workers [11][12][13][14][15][16][17][18][19][20] as an efficient scheme for improving the performance of PLEDs. SWCNTs have high mobility for electrons and this helps in balancing the carrier concentration in the emissive layer.…”