Real-Time Ellipsometric Characterization of Initial Growth Stage of Poly(3,4-ethylene dioxythiophene):Poly(styrene sulfonic acid) Films by Electrospray Deposition

Abstract

Kinetic spectroscopic ellipsometry has been used to study the initial growth stage of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS) films by the electrospray deposition (ESD) method. The real-time spectra analysis revealed that the surface overlayer decreased in thickness, once the first bulk layer monolayer was formed, indicating a smoothening effect as the nucleation-related microstructure coalesced into the bulk layer. Once the coalescence was completed and the nucleation-induced surface roughness layer was stabilized, the underlying bulk layer increased linearly with time. These results originate from the degrees of the evaporation of solvent material during the transfer of the precursors to the surface and/or of the diffusion of deposition precursors after sticking at the growing surface.