Fabrication of PEDOT Thin Films using Oxidative Chemical Vapor Deposition to Enhance The Stability of Perovskite Solar Cells

The practical applications of perovskite solar cells (PSCs) have been hindered by stability issues. One key factor contributing to this limitation is the inherent acidity of the commonly used hole transport layer, poly(3,4-ethylene dioxythiophene):polystyrene sulfonate (PEDOT:PSS), which can compromise the stability of PSC devices. To address this challenge, this study explores an innovative approach that leverages oxidative chemical vapor deposition (oCVD) with antimony pentachloride (SbCl₅) as a liquid oxidant. This method is employed to fabricate stable and ultrathin, highly conformal PEDOT films, offering a promising alternative as a hole transport layer in PSCs. The oCVD-grown PEDOT-Cl thin films, produced using liquid SbCl5 oxidant, exhibit outstanding optoelectronic properties, precise control over nanostructure, stability, and integration capabilities. These qualities make them a robust and efficient choice for use as a hole transport layer in PSCs. Incorporating oCVD PEDOT-Cl thin films as the hole transport layer in PSCs results in a remarkable PCE of 20.74%. This surpasses the PCE of 16.53% achieved by spin-coated PEDOT:PSS thin films treated with the dimethyl sulfoxide (DMSO) polar solvent. Moreover, PSCs incorporating oCVD PEDOT-Cl thin films demonstrate a notable 2.5× enhancement in stability compared to their PEDOT:PSS-DMSO counterparts. This technological advancement paves the way for the development of PSCs with not only high performance but also enhanced stability.<br/><br/><b>Keywords:</b> Oxidative Chemical Vapor Deposition, PEDOT, SbCl₅ Oxidant, Perovskite Solar Cells