The eletronic structure of emeraldine doped in situ from HCl in the gas phase as studied by photoelectron spectroscopy

Abstract

The chemical and electronic structure of spin-coated films of polyaniline in the emeraldine state, treated in-situ with HCl in the gas phase, have been studied for the first time by means of X-ray Photoelectron Spectroscopy (XPS) and Ultra-violet Photoelectron Spectroscopy (UPS). Ultra thin films, of about several hundreds of Ångströms thickness, were spin-coated from a solution of chemically prepared emeraldine in NMP, onto substrates of aluminum or silicon. The salt forms were prepared both by (a) “wet” doping in 1M HCl and (b) the in-situ treatment of the films with HCl in the gas phase. With XPS three different types of chlorine have been observed, two ionic and one covalent. With UPS the valence band spectra of the doped and undoped state, are studied.