The Control of Electronic States Spreading Outside the Conjugated Polymer Surface

Abstract

The surface electronic structures of conjugated regio regular and regio random poly (3- hexylthiophene) (rr-P3HT and rra-P3HT) thin films were studied by near edge X-ray absorption fine structure spectroscopy, ultraviolet photoelectron spectroscopy and Penning ionization electron spectroscopy (PIES). The distribution of the surface electronic states was controlled on rr-P3HT and rra-P3HT thin films with different molecular ordering by varying the coating process and PIES was adopted to observe the electronic states existing outside the surface.

Infrared and photoelectron spectroscopy study of vapor phase deposited poly (3-hexylthiophene)

“…This feature was also observed on HOPG and assigned to delocalized  states 27,46 contributed from C 2p and partial S 3p atomic orbitals. 40 An energy shift of the band at about 3.4 eV was also observed by Hao et al 41 for spin-coated P3HT on gold.…”

“…This localized  state constitutes S 3p and C 2p atomic orbitals. 40 The shift saturates at about 2 nm indicating that the P3HT layer has reached the characteristics of the bulk-like polymer material (as seen in Fig. 3).…”

“…Similar to previous spin-coated samples, only a broad band was observed for the vacuum deposited P3HT films between 5-12 eV which is associated with the  states contributed from main backbones and hexyl side chains. 40,41 The secondary-electron edge at the high BE end and the onset of the valence band of P3HT position was directly determined from the He I spectra. The secondary cutoff energy allows for the estimation of the interface dipole (eD).…”