Ultrafast interface charge transfer dynamics on P3HT/MWCNT nanocomposites probed by resonant Auger spectroscopy

The interfacial electronic structure and charge transfer dynamics of poly-3-hexylthiophene (P3HT) and multi-walled carbon nanotube (Fe-MWCNT) nanocomposites were investigated by near-edge X-ray absorption fine structure (NEXAFS) and resonant Auger (RAS) spectroscopies around the sulfur K-edge. Nanoc...

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Bibliographic Details
Published in:RSC advances 2018-01, Vol.8 (46), p.26416-26422
Main Authors: Garcia-Basabe, Yunier, Ceolin, Denis, Zarbin, Aldo J G, Roman, Lucimara S, Rocco, Maria Luiza M
Format: Article
Language:English
Subjects:
Auger spectroscopy
Charge transfer
Chemistry
Coupling (molecular)
Dynamic structural analysis
Electronic structure
Fine structure
Iron
Molecular chains
Molecular orbitals
Multi wall carbon nanotubes
Nanocomposites
Polymer films
Polymers
Spectrum analysis
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Summary:The interfacial electronic structure and charge transfer dynamics of poly-3-hexylthiophene (P3HT) and multi-walled carbon nanotube (Fe-MWCNT) nanocomposites were investigated by near-edge X-ray absorption fine structure (NEXAFS) and resonant Auger (RAS) spectroscopies around the sulfur K-edge. Nanocomposites with 5 wt% (P3HT/Fe-MWCNT-5%) and 10 wt% (P3HT/Fe-MWCNT-10%) of Fe-MWCNT species were prepared and compared with pristine P3HT film. The quantitative NEXAFS analysis shows a strong π-π interchain interaction of the pristine P3HT polymer film, which is reduced by the presence of the Fe-MWCNT. S-KL L RAS spectra were measured at photon energies corresponding to the main electronic transitions appearing in the S-K edge NEXAFS spectrum. Ultrafast charge transfer times were estimated from the RAS spectra using the core-hole clock approach with the S 1s core-hole lifetime as an internal clock. The π-π interchain charge transfer time increases from 4.7 fs on pristine P3HT polymer to 6.5 fs on the P3HT/Fe-MWCNT-5% nanocomposite. The electronic coupling between P3HT and Fe-MWCNT species occurs mainly through the P3HT π* molecular orbital. The increase of Fe-MWCNT concentration from 5 to 10 wt% reduces the charge transfer rate at the resonance maximum due probably to Fe-MWCNT aggregation, reducing the P3HT and Fe-MWCNT electronic coupling.
ISSN:2046-2069
2046-2069
DOI:10.1039/c8ra04629h