Micro- and Nanopatterning of Highly Conductive PEDOT Thin Films

This work presents two fabrication strategies for the development of organic thin-film devices at the micro- and nano-scales. We make use of non-commercial PEDOT synthesized via liquid-phase oxidative chemical polymerization, using vanadium pentoxide (V₂O₅) as a oxidant. The optimization of this synthetic technique enables the production of homogeneous PEDOT films with a controlled thickness and tunable electrical properties. At the micro-scale, we fabricate a PEDOT microstripe with gold contacts using standard optical lithography and confirm the high electrical performance of the processed PEDOT device. Moreover, at the nanoscale we apply a self-assembling technique, namely the nanosphere lithography, to pattern the thin film over a large area with a hexagonally close-packed array of nanopillars. This technique allows us to achieve individual nanopillar dimensions as small as 255 nm in diameter. The ability to achieve such controlled geometries suggests significant potential for developing organic photonic crystals and metasurfaces. These findings highlight a versatile fabrication framework that bridges standard lithography and unconventional self-assembly, providing a scalable pathway toward advanced organic electronic and tunable photonic devices.