Conductivity of Composite Films Based on Conductive Polymer PEDOT:PSS, Graphene Oxide and Nanoparticles TiO2 for Contact Layers of Perovskite Photovoltaic Structures

Abstract

The electrical properties of composite films based on conductive polymer PEDOT: PSS, graphene oxide (GO), and titanium dioxide nanoparticles (TiO₂) (PEDOT: PSS– TiO₂ and GO–TiO₂) used as contact layers of organic and perovskite photovoltaic structures have been studied. As a result of the study of morphology by atomic force microscopy, it was found that the PEDOT: PSS–TiO₂ and GO–TiO₂ films have a globular structure with a grain size of ~200–300 nm. The current–voltage characteristics of the PEDOT: PSS–TiO₂ and GO–TiO₂ films are measured in the temperature range of 80–300 K, the dependences of the resistivity versus temperature, ρ(T), which have an activation character, are obtained. It is established that as the temperature decreases, the ρ(T) dependences show a transition from large values of the activation energy (570 meV and 329 meV) to lower values (25 meV and 2.2 meV) for the PEDOT: PSS–TiO₂ and GO–TiO₂ films, respectively. The mechanisms of transport of charge carriers in the materials studied are discussed.