Investigation of a polythiophene interface using photoemission spectroscopy in combination with electrospray thin-film deposition

Abstract

The conjugated polymer poly(3-hexylthiophene) (P3HT) was deposited in several steps onto a highly oriented pyrolytic graphite (HOPG) substrate directly from solution in high vacuum, using an electrospray thin-film deposition system. The deposition system was attached to a photoemission spectroscopy setup via in situ sample transfer, allowing characterization in between deposition steps with x-ray and ultraviolet photoemission spectroscopy. The resultant series of spectra enabled the determination of the ionization energy, work function, and highest occupied molecular orbital binding energy of the P3HT overlayer, while giving detailed insight into the orbital alignment and dipole formation at the P3HT/HOPG contact.