Laser nanostructuring of thin films of PEDOT:PSS on ITO: Morphology, molecular structure and electrical properties

Nanostructuring is one promising alternative to modify the functionalities of conducing polymers aiming at applications in technologies like organic solar cells, organic field-effect transistors and organic light-emitting diodes. Nowadays, there is an increasing interest in alternative ways of nanostructuring more economic, quicker and reproducible, avoiding the necessity of stringent environmental conditions like clean rooms, high vacuum or complex mask fabrication. Here we prove that Laser Induced Periodic Surface Structures (LIPSS) can be formed in films of Poly(3,4-ethylenedioxythiophene) complexed with Poly(styrenesulfonate) (PEDOT:PSS) prepared by spin-coating on planar Indium Tin Oxide. PEDOT:PSS has been irradiated with the 4th harmonic of a Nd:YAG laser resulting in LIPSS parallel to the laser polarization with a period close to the laser wavelength. LIPSS morphology has been characterized by Atomic Force Microscopy (AFM) and synchrotron Grazing Incidence Small Angle X-ray Scattering while the film structure was studied by Grazing-Incidence Wide-Angle X-ray Scattering and Raman spectroscopy. To analyze the impact of laser treatment on the electrical properties of PEDOT:PSS, conducive AFM was employed showing that LIPSS partially preserve the original electrical conductivity. These results can be of interest for achieving functional polymer nanostructures by a quick and reproducible approach with no need for clean room conditions.