Thin films of Nickel Phthalocyanine (NiPc) are deposited on a mildly sputtered PEDOT:PSS film spin-coated on Fluorine Tin Oxide coated glass (FTO). The properties of the PEDOT:PSS surface both as-loaded and upon thermal treatment and sputtering, as well as the interfaces between NiPc and PEDOT:PSS are studied by X-Ray and UV Photoelectron Spectroscopies (XPS, UPS), which are well-established methods to study the valence states and the core levels and to investigate both the electronic and the chemical properties of the materials. Surface analysis of the PEDOT:PSS films showed that the annealing has little effect on the structure of the surface, while upon sputtering the insulating PSS film is removed yielding a lower work function value, as well as a build-up of the density of occupied states close to the Fermi level. All of these issues are important, as PEDOT:PSS is used as the hole injecting electrode in polymer-based light emitting diodes. The presence of a PEDOT:PSS film between NiPc and FTO leads to a lower hole-injection barrier.

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