The Polymer Society of Korea

Abstract

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is one of the most widely used conductive polymer for the hole transport layer (HTL) in organic solar cells (OSCs), due to its excellent water processability, high optical transparency, and low cost. However, the hygroscopic nature of the PSS component can lead to the absorption of moisture, resulting in the formation of pinholes and charge recombination sites at the interface, which deteriorate device performance and stability. In this study, we introduce a crosslinking strategy to improve the water stablity of PEDOT:PSS-based HTLs. By simply incorporating a crosslinking agent into the PEDOT:PSS layer, the modified HTL maintain comparable photovoltaic performance to conventional PEDOT:PSS-based devices, while exhibiting significantly enhanced water resistance, operational stability, and mechanical robustness. This approach offers a facile and effective route toward high-efficiency, long-lifetime OSCs.