Elucidation of the Controversial Layer Growth Mechanism of Vapor Phase Polymerization in the Preparation of Conductive Poly(3,4‐ethylenedioxythiophene)‐SiO₂ Hybrid Films

Abstract In recent times, there have been debates to ascertain whether the growth mechanism in vapor phase polymerization is a top‐down or a bottom‐up process. The objective of the present study is to identify the formation mechanisms of the organic–inorganic hybrid film prepared in the gaseous phase on the basis of the practical importance of the hybridization of materials. To this end, poly(3,4‐ethylenedioxythiophene)‐SiO₂ conductive hybrid films with different layered structures are successfully fabricated. The growth mechanism of the layered organic–inorganic conductive hybrid thin film is elucidated by investigating the variations in the morphological and chemical compositions of its surface. Additionally, a cross‐sectional analysis is performed using a scanning electron microscope‐energy dispersive X‐ray spectroscopy and X‐ray photoelectron spectroscopy. The results indicate a “bottom‐up” growth mechanism, wherein the oxidant diffused through the recently formed layer, generating novel layers; this ultimately leads to formation of the organic–inorganic conductive hybrid film. Moreover, the optoelectronic and mechanical properties of the hybrid conductive films are precisely controlled by adjusting the order of incorporation of monomers in the process and the duration of polymerization of each monomer. Thus, this study achieves the fabrication of a mechanically robust and optically enhanced conductive hybrid film.