The modified PEDOT:PSS as cathode interfacial layer for scalable organic solar cells

Abstract

Abstract Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is extensively used as an anode interfacial layer in optoelectronic devices due to its excellent hole-transporting properties and high work function (ϕF). In this study, we propose a simple and cost-effective method to controllably tune the ϕF of PEDOT:PSS from 5.1 eV to 3.95 eV by doping the polyethylenimine ethoxylated (PEIE). The PEIE-doped PEDOT:PSS films can function as a cathode interfacial layer in organic solar cells, showing the comparable performance to a conventional ZnO-based cell. The photoelectric characteristics, surface morphology, and electron transport ability of PEIE-doped PEDOT:PSS films were systematically investigated to elucidate the physical nature of the conversion from hole transport to electron transport. This strategy provides an effective charge transport layer for optoelectronic devices, which is suitable for large-scale, industrial applications.