Unraveling vertical inhomogeneity in vapour phase polymerized PEDOT:Tos films

• The conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) forms a promising alternative to conventional inorganic conductors, where deposition of thin filmsviavapour phase polymerization (VPP) has gained particular interest owing to high electrical conductivity within the plane of the film. The conductivity perpendicular to the film is typically much lower, which may be related not only to preferential alignment of PEDOT crystallites but also to vertical stratification across the film. In this study, we reveal non-linear vertical microstructural variations across VPP PEDOT:Tos thin films, as well as significant differences in doping level between the top and bottom surfaces. The results are consistent with a VPP mechanism based on diffusion-limited transport of polymerization precursors. Conducting polymer films with vertical inhomogeneity may find applications in gradient-index optics, functionally graded thermoelectrics, and optoelectronic devices requiring gradient doping. 

Keyword

Conducting polymers

Crystallites

Gradient index optics

Optoelectronic devices

Polymerization

Semiconductor doping

Thin films

Diffusion-limited transport

Functionally graded

High electrical conductivity

Mechanism-based

Microstructural variation

Poly(3

4 ethylenedioxythiophene) (PEDOT)

Thermoelectrics

Vertical stratification

Polymer films

Publication and Content Type

ref (subject category)

art (subject category)