Unoccupied conduction band of chloroaluminum phthalocyanine

Abstract

The electronic structure of the unoccupied conduction band of polycrystalline chloroaluminum phthalocyanine was investigated by X-ray absorption spectroscopy (XAS) near the Cl K-edge. XAS spectra were recorded in total electron yield (TEY) and partial Auger electron yield (AEY) modes. Partial AEY spectra were measured using normal and spectator Cl KL 2,3 L 2,3 Auger yields as a function of photon energy. Although the TEY spectrum showed a broad shape; that was difficult to deconvolute curve fitting, the normal and spectator AEY spectra clearly showed that Cl 1s → σ*(Cl-Al) transition splits into two competitive peaks attributed to the core excitons (localized with a core hole) and conduction band (delocalized without a core hole). The existence of a band-like peak in the Cl K-edge XAS is evidence that the Cl axial ligand participates in forming the conduction band. Thus, band-like electron transport is expected to occur in the oligomer-like (-Al-Cl-Al-) site.

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

“…The analysis of the SP1 spectator shi parameters of the RAS spectra measured at these three photon energies shows that the electron delocalization degree of electron excited of p* symmetry (2471.9 eV) and s* (2474.4 eV) states is higher for P3HT/ITO than P3HT/Fe-MWCNT-5%. This s* transition presents a transition moment perpendicular to the polymer backbone, as previously discussed by H. Ikeura-Sekiguchi et al 55 and R. Onoki et al 57 However, at photon energy corresponding to the resonance maximum (2473.2 eV) the electron delocalization degree is higher for the P3HT/Fe-MWCNT-5% nanocomposite compared to P3HT/ITO. These results show that the electronic coupling between P3HT and Fe-MWCNT depends on the character of the electronic excited states.…”

“…Comparing S 1s NEXAFS spectra of regioregular P3HT lm and polycrystalline powder (RR-P3HT) it was shown a reduction in the LUMO energy level which the authors suggested as being directly associated to the p-p intermolecular interaction present for the regioregular polymeric lm. 55 This would explain the remarkable signal related to the p* transition well visualized in the spectrum of Fig. 1c for pristine P3HT, which also demonstrate the quality of the lm deposition.…”