Photography-Inspired Patterned Vapor Phase Polymerization of Conductive PEDOT on Rigid and Stretchable Substrates

The conductive polymers poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole are widely used in organic optoelectronic, bioelectronic, and electrochromic applications. However, a general process for forming highly conductive films with high spatial resolution on various substrates is lacking. This work describes a technique for forming PEDOT and polypyrrole films with high spatial resolution using vapor-phase polymerization (VPP). The process, reminiscent of classical black-and-white photography, employs a photosensitive VPP initiating film. UV light selectively deactivates the film, allowing oxidative polymerization in unexposed regions. Substrates are modified with N-3-(trimethoxysilyl)propylaniline to enhance adhesion. Optimizing the initiating film composition and exposure conditions achieves conductive lines as narrow as 15 μm with PEDOT conductivities over 1000 S cm–1. Mechanistic studies using X-ray photoelectron spectroscopy, UV–visible spectroscopy, and Fourier transform infrared spectroscopy suggest a critical role of oxidative decomposition by photoinitiated ligand-to-metal charge transfer. The resulting conductive patterns exhibit abrasion resistance on glass, retain conductivity when stretched on elastomers, and enable two-color electrochromic displays.