Changing the Electrical Conductivity of Pedot:pss Films via Hybrid Doping with Inorganic and Organic Semiconductors

In the search for sustainable alternatives to conventional transparent electrodes, PEDOT:PSS stands out for its transparency, aqueous processability, and flexibility. However, its low conductivity in the pristine state, mainly due to the insulating PSS component, limits its application. In this work, two separate doping approaches were investigated: the first involved the addition of an inorganic semiconductor (TiO2 nanoparticles) to the PEDOT:PSS dispersion, while the second consisted of blending PEDOT:PSS with the organic semiconductor poly(N-vinylcarbazole) (PVK). The hybrid films were obtained through spin coating and then annealed to enhance their morphological uniformity. A custom-built four-point probe system was developed to perform accurate electrical characterization of the hybrid films. Experimental results show an increase in sheet resistance upon doping. This effect is ascribed not only to morphological disorder and limited percolation pathways, but also to the absence of photoexcitation in the dopant semiconductors under dark conditions, which prevents their contribution to charge transport.