Extremely stable organic photovoltaic incorporated with WOx doped PEDOT:PSS anode buffer layer

Abstract

The state of interfaces between organic semiconductors and/or metals in organic devices severely impacts their performance and stability. The commonly used organic semiconductor PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)) is hygroscopic in nature and can therefore be easily damaged if exposed to air and/or light illumination. In this study, we doped PEDOT:PSS with WO_x nanocrystallites and found that organic photovoltaics (OPVs) with the WO_x doped PEDOT:PSS degrade only by 5%, while OPVs with undoped PEDOT:PSS retain only 23% of their initial power conversion efficiency (PCE) after storing for 5000 h in air. Also, doping PEDOT:PSS with WO_x enhances the initial PCE by ∼13%, owing to reduced leakage current density and better Ohmic contact between the PEDOT:PSS and the anode.